diff --git a/.env.example b/.env.example
index efc33ca..d1be168 100644
--- a/.env.example
+++ b/.env.example
@@ -1,24 +1,27 @@
-# ---- Supabase (auth) ----
-# Public: safe to expose to the browser. Used for GitHub OAuth sign-in only.
-NEXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co
-NEXT_PUBLIC_SUPABASE_ANON_KEY=your-anon-key
+# ---- GitHub OAuth (app-native auth, server-only) ----
+# From your GitHub OAuth App (Settings > Developer settings > OAuth Apps).
+# All server-only — NEVER prefix with NEXT_PUBLIC_.
+GITHUB_OAUTH_CLIENT_ID=Iv1.your-client-id
+GITHUB_OAUTH_CLIENT_SECRET=your-client-secret
+# Callback is derived at runtime from the request origin (${origin}/auth/callback)
+# — no callback env needed. The OAuth App's registered Authorization callback URL
+# must match the host you serve on (prod = https://llmapikey.vercel.app/auth/callback,
+# local dev = http://localhost:3000/auth/callback). GitHub OAuth Apps allow only
+# ONE callback, so reach the app on its canonical domain.
+# Session signing secret (HS256). >=32 bytes. Generate: openssl rand -base64 48
+AUTH_SESSION_SECRET=change-me-to-a-32-byte-or-longer-random-string
 
 # ---- Postgres (direct, server-only) ----
-# Supabase pooler connection string (Project Settings > Database > Connection
-# string > "Transaction" pooler, port 6543). Reaches the unexposed `llmapikey`
-# schema. NEVER expose to the client. The connecting role must own/bypass RLS on
-# the llmapikey schema (project `postgres` user).
-DATABASE_URL=postgresql://postgres.your-ref:password@aws-0-region.pooler.supabase.com:6543/postgres
+# Supabase pooler connection string. The Supabase Vercel integration provisions
+# this as POSTGRES_URL (Transaction pooler, port 6543). Reaches the unexposed
+# `llmapikey` schema. NEVER expose to the client. The connecting role must
+# own/bypass RLS on the llmapikey schema (project `postgres` user).
+POSTGRES_URL=postgresql://postgres.your-ref:password@aws-0-region.pooler.supabase.com:6543/postgres
 
 # ---- OpenRouter (server-only secret) ----
-# Master Provisioning key used to mint per-user keys. NEVER expose to the client.
-OPENROUTER_PROVISIONING_KEY=sk-or-v1-provisioning-...
-
-# ---- App config ----
-# Public repo URL for the soft star nudge.
-NEXT_PUBLIC_REPO_URL=https://github.com/your-org/llmapikey
-# Model id shown in /docs and used as the documented target.
-NEXT_PUBLIC_OPENROUTER_MODEL=minimax/minimax-m3
+# Master management/provisioning key used to mint per-user keys. NEVER expose to
+# the client.
+OPENROUTER_MANAGEMENT_KEY=sk-or-v1-provisioning-...
 
 # ---- Provisioning controls (server-only) ----
 # Feature flag: live key minting is OFF until OpenRouter ToS gate (Phase 1)
diff --git a/README.md b/README.md
index 65de3bf..0cc41e6 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,8 @@
 
 Free, capped OpenRouter API key giveaway — one key per GitHub account.
 
-Next.js (App Router, JS + JSDoc) on Vercel. GitHub sign-in via Supabase Auth.
+Next.js (App Router, JS + JSDoc) on Vercel. App-native GitHub OAuth (Arctic +
+jose stateless signed-cookie session) — Supabase is the Postgres host only.
 Per-user OpenRouter keys are minted from the owner's master Provisioning key,
 each capped at a daily USD limit. Key records live in a dedicated, unexposed
 `llmapikey` Postgres schema reached only by a server-side direct connection.
@@ -14,17 +15,27 @@ each capped at a daily USD limit. Key records live in a dedicated, unexposed
 ## Stack
 
 - **Next.js 15** App Router, plain JS + JSDoc (no TypeScript)
-- **Supabase Auth** — GitHub OAuth provider (sessions via `@supabase/ssr`)
+- **App-native GitHub OAuth** — [Arctic](https://arcticjs.dev) for the OAuth2
+  dance, [jose](https://github.com/panva/jose) for a stateless HS256 signed-cookie
+  session. No auth provider; GitHub → `/auth/callback` directly. `read:user` scope
+  only; the access token is read once and discarded (no token storage).
 - **Postgres** (`postgres` npm) — direct connection to the unexposed `llmapikey`
-  schema; the anon role can never reach `api_keys`
+  schema; the anon role can never reach `api_keys`. (Supabase = DB host only.)
 - **OpenRouter Provisioning API** — mints per-user keys
 
 ## Architecture notes
 
 - **Identity anchor:** the numeric, immutable GitHub `provider_id` (not the
   mutable login). One key per `github_user_id`, enforced by a DB unique constraint.
-- **Server-only secrets:** `DATABASE_URL` and `OPENROUTER_PROVISIONING_KEY` are
-  guarded by the `server-only` package and never reach the client bundle.
+- **Server-only secrets:** `POSTGRES_URL`, `OPENROUTER_MANAGEMENT_KEY`,
+  `GITHUB_OAUTH_CLIENT_SECRET`, and `AUTH_SESSION_SECRET` are guarded by the
+  `server-only` package and never reach the client bundle (no `NEXT_PUBLIC_`).
+- **Stateless session:** signed JWT (HS256) in an httpOnly+Secure+SameSite=Lax
+  cookie; no DB session table. CSRF handled by a single-use `state` cookie
+  verified at the callback; `next` redirects pass through a same-origin sanitizer.
+- **Schema isolation is structural:** the `llmapikey` schema is unexposed to
+  PostgREST and reached only via the direct PG client (deny-all RLS as defense in
+  depth). The app ships no anon DB client, so the isolation holds by construction.
 - **Reserve-then-mint:** a `pending` row is inserted (ON CONFLICT DO NOTHING)
   before minting, so concurrent double-submits yield exactly one OpenRouter key.
 - **Schema isolation:** `llmapikey` is NOT added to PostgREST exposed schemas;
@@ -45,28 +56,32 @@ each capped at a daily USD limit. Key records live in a dedicated, unexposed
 2. **Environment** — copy `.env.example` to `.env.local` and fill in values.
    | Var | Purpose |
    |-----|---------|
-   | `NEXT_PUBLIC_SUPABASE_URL` | Supabase project URL (public) |
-   | `NEXT_PUBLIC_SUPABASE_ANON_KEY` | Supabase anon key (public, auth UI only) |
-   | `DATABASE_URL` | Supabase **transaction pooler** string (server-only) |
-   | `OPENROUTER_PROVISIONING_KEY` | Master Provisioning key (server-only) |
-   | `NEXT_PUBLIC_REPO_URL` | Repo URL for the soft star nudge |
-   | `NEXT_PUBLIC_OPENROUTER_MODEL` | Model id shown in `/docs` |
+   | `GITHUB_OAUTH_CLIENT_ID` | GitHub OAuth App client id (server-only) |
+   | `GITHUB_OAUTH_CLIENT_SECRET` | GitHub OAuth App client secret (server-only) |
+   | `AUTH_SESSION_SECRET` | Session JWT signing secret, ≥32 bytes (`openssl rand -base64 48`) |
+   | `POSTGRES_URL` | Supabase **transaction pooler** string (server-only; provisioned by the Supabase Vercel integration) |
+   | `OPENROUTER_MANAGEMENT_KEY` | Master management/provisioning key (server-only) |
    | `PROVISIONING_ENABLED` | `false` until Phase 1 ToS gate clears |
    | `MAX_TOTAL_KEYS` | Kill-switch: stop minting past N active keys |
    | `KEY_DAILY_LIMIT_USD` | Per-key daily cap sent to OpenRouter |
    | `KEY_EXPIRY_DAYS` | Key lifetime (sets `expires_at`) |
    | `ADMIN_GITHUB_USER_IDS` | Admin allowlist — numeric GitHub `provider_id`s, CSV (server-only) |
 3. **Database** — apply the migration to a **staging branch first**, then prod
-   (Supabase SQL editor or `psql "$DATABASE_URL" -f ...`):
+   (Supabase SQL editor or `psql "$POSTGRES_URL" -f ...`):
    ```bash
-   psql "$DATABASE_URL" -f supabase/migrations/0001_llmapikey_schema_and_api_keys.up.sql
+   psql "$POSTGRES_URL" -f supabase/migrations/0001_llmapikey_schema_and_api_keys.up.sql
    ```
    Do NOT add `llmapikey` to the project's PostgREST "Exposed schemas".
    Rollback: `...0001_...down.sql`.
-4. **GitHub OAuth** — register a GitHub OAuth App; set the client id/secret in
-   the Supabase dashboard (Auth > Providers > GitHub), callback
-   `https://<project>.supabase.co/auth/v1/callback`. Add localhost + your Vercel
-   domain to Supabase Auth redirect URLs.
+4. **GitHub OAuth App** — register one at GitHub > Settings > Developer settings >
+   OAuth Apps. Authorization callback URL points at the **app** (not Supabase):
+   `https://llmapikey.vercel.app/auth/callback` for prod (use a separate dev app
+   with `http://localhost:3000/auth/callback` for local). Copy the Client ID +
+   Secret into `GITHUB_OAUTH_CLIENT_ID` / `GITHUB_OAUTH_CLIENT_SECRET`. The callback
+   is derived from the request origin at runtime, so no callback env is needed —
+   but reach the app on its **canonical domain** (the one registered above);
+   GitHub rejects sign-in arriving on any other host (e.g. Vercel deployment-hash
+   or preview URLs).
 5. **Run**
    ```bash
    npm run dev      # http://localhost:3000
@@ -75,5 +90,8 @@ each capped at a daily USD limit. Key records live in a dedicated, unexposed
 
 ## Deploy (gated)
 
-Auto-build on Vercel is intentionally disabled (see `vercel.json`). Promote
-manually once the Phase 1 ToS gate clears and `PROVISIONING_ENABLED=true`.
+Git-triggered builds on Vercel are enabled (`vercel.json` →
+`git.deploymentEnabled: true`). Builds and deploys do NOT start the giveaway:
+live key minting is gated independently by `PROVISIONING_ENABLED`. Keep
+`PROVISIONING_ENABLED=false` in the Vercel environment until the Phase 1
+OpenRouter ToS gate clears; only then set it `true` to begin minting.
diff --git a/app/auth/callback/route.js b/app/auth/callback/route.js
index a371db7..fae6dba 100644
--- a/app/auth/callback/route.js
+++ b/app/auth/callback/route.js
@@ -1,35 +1,58 @@
 import { NextResponse } from "next/server";
+import { cookies } from "next/headers";
 
-import { createServerAuthClient } from "@/lib/supabase/server-client";
+import { getGithubOAuth } from "@/lib/auth/github-oauth";
+import { createSession } from "@/lib/auth/session";
+import { sanitizeNext } from "@/lib/auth/sanitize-next";
 
 /**
- * OAuth callback: exchange the GitHub auth code for a Supabase session cookie,
- * then redirect to `next` (default /dashboard).
+ * GitHub OAuth callback. Verify CSRF state, exchange the code, read the public
+ * profile once (`id` + `login`), mint the session cookie, then redirect to the
+ * stashed `next`. The access token is never stored.
  *
  * @param {Request} request
  */
 export async function GET(request) {
   const { searchParams, origin } = new URL(request.url);
   const code = searchParams.get("code");
-  const next = sanitizeNext(searchParams.get("next"));
+  const state = searchParams.get("state");
 
-  if (code) {
-    const supabase = await createServerAuthClient();
-    const { error } = await supabase.auth.exchangeCodeForSession(code);
-    if (!error) {
-      return NextResponse.redirect(`${origin}${next}`);
-    }
+  const cookieStore = await cookies();
+  const storedState = cookieStore.get("oauth_state")?.value;
+  const next = sanitizeNext(cookieStore.get("oauth_next")?.value);
+
+  // Clear the transient cookies regardless of outcome.
+  cookieStore.delete("oauth_state");
+  cookieStore.delete("oauth_next");
+
+  if (!code || !state || !storedState || state !== storedState) {
+    return NextResponse.redirect(`${origin}/?auth_error=1`);
   }
-  return NextResponse.redirect(`${origin}/?auth_error=1`);
-}
 
-/**
- * Only allow same-origin relative paths to avoid open-redirect.
- *
- * @param {string | null} next
- * @returns {string}
- */
-function sanitizeNext(next) {
-  if (next && next.startsWith("/") && !next.startsWith("//")) return next;
-  return "/dashboard";
+  try {
+    const oauth = getGithubOAuth(origin);
+    const tokens = await oauth.validateAuthorizationCode(code);
+    const accessToken = tokens.accessToken();
+
+    const res = await fetch("https://api.github.com/user", {
+      headers: {
+        Authorization: `Bearer ${accessToken}`,
+        "User-Agent": "llmapikey",
+        Accept: "application/vnd.github+json",
+      },
+    });
+    if (!res.ok) return NextResponse.redirect(`${origin}/?auth_error=1`);
+
+    const profile = await res.json();
+    const githubUserId = String(profile.id);
+    // Anchor on the numeric provider_id, never the mutable login.
+    if (!/^\d+$/.test(githubUserId)) {
+      return NextResponse.redirect(`${origin}/?auth_error=1`);
+    }
+
+    await createSession({ githubUserId, githubUsername: String(profile.login) });
+    return NextResponse.redirect(`${origin}${next}`);
+  } catch {
+    return NextResponse.redirect(`${origin}/?auth_error=1`);
+  }
 }
diff --git a/app/auth/login/route.js b/app/auth/login/route.js
new file mode 100644
index 0000000..7af0f9f
--- /dev/null
+++ b/app/auth/login/route.js
@@ -0,0 +1,37 @@
+import { NextResponse } from "next/server";
+import { cookies } from "next/headers";
+import { generateState } from "arctic";
+
+import { getGithubOAuth, GITHUB_SCOPES } from "@/lib/auth/github-oauth";
+import { sanitizeNext } from "@/lib/auth/sanitize-next";
+
+/**
+ * Start GitHub OAuth: create CSRF `state`, stash it + the sanitized `next` in
+ * short-lived httpOnly cookies, then 302 to GitHub's authorize URL.
+ *
+ * @param {Request} request
+ */
+export async function GET(request) {
+  const { searchParams, origin } = new URL(request.url);
+  const next = sanitizeNext(searchParams.get("next"));
+
+  const state = generateState();
+  const oauth = getGithubOAuth(origin);
+  const url = oauth.createAuthorizationURL(state, GITHUB_SCOPES);
+
+  // 10-min, single-use CSRF state + the post-login destination. Lax so they
+  // survive the top-level redirect back from GitHub. Cookies set via the
+  // cookies() store attach to the redirect response in route handlers.
+  const attrs = {
+    httpOnly: true,
+    secure: true,
+    sameSite: "lax",
+    path: "/",
+    maxAge: 600,
+  };
+  const cookieStore = await cookies();
+  cookieStore.set("oauth_state", state, attrs);
+  cookieStore.set("oauth_next", next, attrs);
+
+  return NextResponse.redirect(url);
+}
diff --git a/app/auth/sign-out/route.js b/app/auth/sign-out/route.js
index fced70d..385ed6b 100644
--- a/app/auth/sign-out/route.js
+++ b/app/auth/sign-out/route.js
@@ -1,14 +1,14 @@
 import { NextResponse } from "next/server";
 
-import { createServerAuthClient } from "@/lib/supabase/server-client";
+import { clearSession } from "@/lib/auth/session";
 
 /**
- * Sign out: clear the Supabase session and redirect home.
+ * Sign out: clear the session cookie and redirect home. POST (the header uses a
+ * `method="post"` form); 303 turns the POST into a GET on the redirect.
  *
  * @param {Request} request
  */
 export async function POST(request) {
-  const supabase = await createServerAuthClient();
-  await supabase.auth.signOut();
+  await clearSession();
   return NextResponse.redirect(new URL("/", request.url), { status: 303 });
 }
diff --git a/components/sign-in-with-github-button.js b/components/sign-in-with-github-button.js
index cf60f37..2b17853 100644
--- a/components/sign-in-with-github-button.js
+++ b/components/sign-in-with-github-button.js
@@ -1,31 +1,17 @@
-"use client";
-
-import { useState } from "react";
-
-import { createBrowserSupabaseClient } from "@/lib/supabase/browser-client";
+import Link from "next/link";
 
 /**
- * GitHub sign-in button. Kicks off Supabase OAuth; minimal scope (read:user).
+ * GitHub sign-in button. A plain link to the server-side OAuth start route
+ * (`/auth/login`), which creates the CSRF state and redirects to GitHub. No
+ * client-side auth SDK needed.
  *
  * @param {{ next?: string, label?: string }} props
  */
 export function SignInWithGithubButton({ next = "/dashboard", label = "Sign in with GitHub" }) {
-  const [loading, setLoading] = useState(false);
-
-  async function handleSignIn() {
-    setLoading(true);
-    const supabase = createBrowserSupabaseClient();
-    const redirectTo = `${window.location.origin}/auth/callback?next=${encodeURIComponent(next)}`;
-    const { error } = await supabase.auth.signInWithOAuth({
-      provider: "github",
-      options: { redirectTo, scopes: "read:user" },
-    });
-    if (error) setLoading(false); // on success the browser navigates away
-  }
-
+  const href = `/auth/login?next=${encodeURIComponent(next)}`;
   return (
-    <button className="btn" onClick={handleSignIn} disabled={loading}>
-      {loading ? "Redirecting…" : label}
-    </button>
+    <Link className="btn" href={href}>
+      {label}
+    </Link>
   );
 }
diff --git a/components/site-header.js b/components/site-header.js
index 3f5d023..0aa0608 100644
--- a/components/site-header.js
+++ b/components/site-header.js
@@ -1,21 +1,18 @@
 import Link from "next/link";
 
-import { createServerAuthClient } from "@/lib/supabase/server-client";
+import { getCurrentGithubIdentity } from "@/lib/auth/current-github-identity";
 
 /**
  * Session-aware header (server component). Shows Dashboard + sign-out when
- * authenticated; just Docs otherwise. Display only — `user_name` is fine here.
+ * authenticated; just Docs otherwise. Display only — the login is fine here.
  */
 export async function SiteHeader() {
   let username = null;
   try {
-    const supabase = await createServerAuthClient();
-    const {
-      data: { user },
-    } = await supabase.auth.getUser();
-    username = user?.user_metadata?.user_name ?? null;
+    const identity = await getCurrentGithubIdentity();
+    username = identity?.githubUsername ?? null;
   } catch {
-    username = null; // auth not configured (no env) — render signed-out header
+    username = null; // auth not configured (no secret) — render signed-out header
   }
 
   return (
diff --git a/lib/auth/current-github-identity.js b/lib/auth/current-github-identity.js
index 94c2b08..e9873b5 100644
--- a/lib/auth/current-github-identity.js
+++ b/lib/auth/current-github-identity.js
@@ -1,6 +1,6 @@
 import "server-only";
 
-import { createServerAuthClient } from "@/lib/supabase/server-client";
+import { readSession } from "@/lib/auth/session";
 
 /**
  * @typedef {Object} GithubIdentity
@@ -9,37 +9,15 @@ import { createServerAuthClient } from "@/lib/supabase/server-client";
  */
 
 /**
- * Resolve the current GitHub identity from the validated server session.
+ * Resolve the current GitHub identity from the signed session cookie.
  *
- * Identity anchor: `provider_id` — the numeric, immutable GitHub id. NOT
- * `user_name` (the mutable login — a rename could otherwise mint a second key)
- * and NOT `sub` (the Supabase user UUID). `user_metadata` is end-user-mutable,
- * so it scopes queries server-side only and is never used as an RLS/auth claim.
- *
- * Uses `getUser()` (validates the token with Supabase), not `getSession()`.
+ * Identity anchor: `provider_id` — the numeric, immutable GitHub id. NOT the
+ * mutable login (a rename could otherwise mint a second key). The numeric
+ * invariant is enforced inside `readSession` (defense in depth) and again at
+ * mint time in the OAuth callback. `githubUsername` is display-only.
  *
  * @returns {Promise<GithubIdentity | null>} null when unauthenticated.
- * @throws if a session exists but its GitHub metadata is missing/non-numeric.
  */
 export async function getCurrentGithubIdentity() {
-  const supabase = await createServerAuthClient();
-  const {
-    data: { user },
-  } = await supabase.auth.getUser();
-  if (!user) return null;
-
-  const meta = user.user_metadata ?? {};
-  if (meta.provider_id == null || meta.user_name == null) {
-    throw new Error(
-      "GitHub identity missing provider_id/user_name in user_metadata",
-    );
-  }
-
-  const githubUserId = String(meta.provider_id);
-  // Assert numeric — guards against accidentally anchoring on the mutable login.
-  if (!/^\d+$/.test(githubUserId)) {
-    throw new Error(`Expected numeric GitHub provider_id, got: ${githubUserId}`);
-  }
-
-  return { githubUserId, githubUsername: String(meta.user_name) };
+  return readSession();
 }
diff --git a/lib/auth/github-oauth.js b/lib/auth/github-oauth.js
new file mode 100644
index 0000000..e7e0fa4
--- /dev/null
+++ b/lib/auth/github-oauth.js
@@ -0,0 +1,33 @@
+import "server-only";
+
+import { GitHub } from "arctic";
+
+/**
+ * GitHub OAuth scopes. `read:user` is enough to read the public profile
+ * (`id` + `login`) at the callback; no email scope, no token storage.
+ */
+export const GITHUB_SCOPES = ["read:user"];
+
+/**
+ * Build the Arctic GitHub OAuth client.
+ *
+ * Redirect URI is derived from the request `origin` (`${origin}/auth/callback`),
+ * so no callback env is needed. GitHub validates this against the OAuth App's
+ * registered callback, so requests reaching the app on a non-registered host
+ * (e.g. a Vercel deployment-hash URL) will fail at GitHub — link only the
+ * canonical domain. Login and callback MUST pass the same origin so the
+ * `redirect_uri` matches across the authorize + token-exchange steps.
+ *
+ * @param {string} origin Request origin, e.g. `https://llmapikey.vercel.app`.
+ * @returns {import('arctic').GitHub}
+ */
+export function getGithubOAuth(origin) {
+  const clientId = process.env.GITHUB_OAUTH_CLIENT_ID;
+  const clientSecret = process.env.GITHUB_OAUTH_CLIENT_SECRET;
+  if (!clientId || !clientSecret) {
+    throw new Error(
+      "Missing GITHUB_OAUTH_CLIENT_ID / GITHUB_OAUTH_CLIENT_SECRET",
+    );
+  }
+  return new GitHub(clientId, clientSecret, `${origin}/auth/callback`);
+}
diff --git a/lib/auth/sanitize-next.js b/lib/auth/sanitize-next.js
new file mode 100644
index 0000000..ae508a7
--- /dev/null
+++ b/lib/auth/sanitize-next.js
@@ -0,0 +1,12 @@
+/**
+ * Open-redirect guard. Only same-origin relative paths are allowed; anything
+ * else (absolute URLs, protocol-relative `//host`, missing) falls back to
+ * `/dashboard`. Shared by `/auth/login` and `/auth/callback`.
+ *
+ * @param {string | null | undefined} next
+ * @returns {string}
+ */
+export function sanitizeNext(next) {
+  if (next && next.startsWith("/") && !next.startsWith("//")) return next;
+  return "/dashboard";
+}
diff --git a/lib/auth/session-token.js b/lib/auth/session-token.js
new file mode 100644
index 0000000..fe01ac6
--- /dev/null
+++ b/lib/auth/session-token.js
@@ -0,0 +1,62 @@
+import { SignJWT, jwtVerify } from "jose";
+
+/**
+ * Pure JWT sign/verify for the session token — no cookies, no `server-only`, so
+ * it is unit-testable in node:test. `session.js` wraps these with the cookie
+ * store. HS256 over the GitHub identity; subject = numeric `provider_id`.
+ */
+
+export const SESSION_MAX_AGE_SECONDS = 60 * 60 * 24 * 7; // 7 days
+
+/**
+ * Encode + validate the signing secret. Throws (config error) when missing or
+ * shorter than 32 bytes.
+ *
+ * @param {string | undefined} raw
+ * @returns {Uint8Array}
+ */
+export function encodeSecret(raw) {
+  if (!raw || Buffer.byteLength(raw, "utf8") < 32) {
+    throw new Error(
+      "AUTH_SESSION_SECRET must be set and at least 32 bytes long",
+    );
+  }
+  return new TextEncoder().encode(raw);
+}
+
+/**
+ * Sign the identity into a JWT.
+ *
+ * @param {{ githubUserId: string, githubUsername: string }} identity
+ * @param {Uint8Array} secret
+ * @returns {Promise<string>}
+ */
+export function signSessionToken({ githubUserId, githubUsername }, secret) {
+  return new SignJWT({ login: githubUsername })
+    .setProtectedHeader({ alg: "HS256" })
+    .setSubject(githubUserId)
+    .setIssuedAt()
+    .setExpirationTime("7d")
+    .sign(secret);
+}
+
+/**
+ * Verify a JWT and extract the identity. Returns null on any token error
+ * (missing/tampered/expired) or when the subject is not a numeric provider_id.
+ *
+ * @param {string | undefined | null} token
+ * @param {Uint8Array} secret
+ * @returns {Promise<{ githubUserId: string, githubUsername: string } | null>}
+ */
+export async function verifySessionToken(token, secret) {
+  if (!token) return null;
+  try {
+    const { payload } = await jwtVerify(token, secret);
+    const githubUserId = String(payload.sub ?? "");
+    // Re-assert the numeric provider_id invariant (defense in depth).
+    if (!/^\d+$/.test(githubUserId)) return null;
+    return { githubUserId, githubUsername: String(payload.login ?? "") };
+  } catch {
+    return null;
+  }
+}
diff --git a/lib/auth/session.js b/lib/auth/session.js
new file mode 100644
index 0000000..96f5be6
--- /dev/null
+++ b/lib/auth/session.js
@@ -0,0 +1,65 @@
+import "server-only";
+
+import { cookies } from "next/headers";
+
+import {
+  SESSION_MAX_AGE_SECONDS,
+  encodeSecret,
+  signSessionToken,
+  verifySessionToken,
+} from "./session-token";
+
+/**
+ * Stateless signed-cookie session. The app has no user table — identity is just
+ * the GitHub `provider_id` (numeric, immutable) + login, carried in an HS256 JWT
+ * inside an httpOnly cookie. No DB session row; on expiry the user re-logs in.
+ * JWT logic lives in `session-token.js` (testable); this module wires cookies.
+ */
+
+const COOKIE_NAME = "llmapikey_session";
+
+/**
+ * Cookie attributes. SameSite=Lax (not Strict) so the cookie rides the
+ * top-level GET redirect back from GitHub; Strict would drop it.
+ */
+const COOKIE_ATTRS = {
+  httpOnly: true,
+  secure: true,
+  sameSite: "lax",
+  path: "/",
+  maxAge: SESSION_MAX_AGE_SECONDS,
+};
+
+/** @returns {Uint8Array} */
+function secret() {
+  return encodeSecret(process.env.AUTH_SESSION_SECRET);
+}
+
+/**
+ * Sign the identity into the session cookie.
+ *
+ * @param {{ githubUserId: string, githubUsername: string }} identity
+ */
+export async function createSession(identity) {
+  const jwt = await signSessionToken(identity, secret());
+  const cookieStore = await cookies();
+  cookieStore.set(COOKIE_NAME, jwt, COOKIE_ATTRS);
+}
+
+/**
+ * Read + verify the session cookie. Token errors → null; config errors (bad
+ * `AUTH_SESSION_SECRET`) propagate (intentional fail-fast).
+ *
+ * @returns {Promise<{ githubUserId: string, githubUsername: string } | null>}
+ */
+export async function readSession() {
+  const cookieStore = await cookies();
+  const token = cookieStore.get(COOKIE_NAME)?.value;
+  return verifySessionToken(token, secret());
+}
+
+/** Clear the session cookie (sign-out). */
+export async function clearSession() {
+  const cookieStore = await cookies();
+  cookieStore.delete(COOKIE_NAME);
+}
diff --git a/lib/supabase/browser-client.js b/lib/supabase/browser-client.js
deleted file mode 100644
index 313f6d8..0000000
--- a/lib/supabase/browser-client.js
+++ /dev/null
@@ -1,23 +0,0 @@
-"use client";
-
-import { createBrowserClient } from "@supabase/ssr";
-
-/**
- * Browser Supabase client — anon key only.
- *
- * SCOPE: auth UI only (sign-in / sign-out / session). This client MUST NEVER be
- * used to read or write `llmapikey.api_keys`; that table is server-only and the
- * anon role is denied by RLS. See lib/supabase/server-client.js.
- *
- * @returns {import('@supabase/supabase-js').SupabaseClient}
- */
-export function createBrowserSupabaseClient() {
-  const url = process.env.NEXT_PUBLIC_SUPABASE_URL;
-  const anonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
-  if (!url || !anonKey) {
-    throw new Error(
-      "Missing NEXT_PUBLIC_SUPABASE_URL or NEXT_PUBLIC_SUPABASE_ANON_KEY",
-    );
-  }
-  return createBrowserClient(url, anonKey);
-}
diff --git a/lib/supabase/server-client.js b/lib/supabase/server-client.js
deleted file mode 100644
index e7007e0..0000000
--- a/lib/supabase/server-client.js
+++ /dev/null
@@ -1,51 +0,0 @@
-import "server-only";
-
-import { createServerClient } from "@supabase/ssr";
-import { cookies } from "next/headers";
-
-/**
- * Cookie-based Supabase client (anon key) for reading/refreshing the auth
- * session on the server. Use this to know WHO the request is, never to touch
- * `api_keys` — that table lives in the unexposed `llmapikey`
- * schema and is reached only via the direct Postgres client (lib/db).
- *
- * In Server Components cookie writes throw; we swallow that — session refresh
- * still works in route handlers / server actions where writes are allowed.
- *
- * @returns {Promise<import('@supabase/supabase-js').SupabaseClient>}
- */
-export async function createServerAuthClient() {
-  const url = requireEnv("NEXT_PUBLIC_SUPABASE_URL");
-  const anonKey = requireEnv("NEXT_PUBLIC_SUPABASE_ANON_KEY");
-  const cookieStore = await cookies();
-
-  return createServerClient(url, anonKey, {
-    cookies: {
-      getAll() {
-        return cookieStore.getAll();
-      },
-      setAll(cookiesToSet) {
-        try {
-          for (const { name, value, options } of cookiesToSet) {
-            cookieStore.set(name, value, options);
-          }
-        } catch {
-          // Called from a Server Component — cookies are read-only here.
-          // Safe to ignore: middleware/route handlers refresh the session.
-        }
-      },
-    },
-  });
-}
-
-/**
- * @param {string} name
- * @returns {string}
- */
-function requireEnv(name) {
-  const value = process.env[name];
-  if (!value) {
-    throw new Error(`Missing required environment variable: ${name}`);
-  }
-  return value;
-}
diff --git a/middleware.js b/middleware.js
deleted file mode 100644
index 04b28b7..0000000
--- a/middleware.js
+++ /dev/null
@@ -1,41 +0,0 @@
-import { createServerClient } from "@supabase/ssr";
-import { NextResponse } from "next/server";
-
-/**
- * Refresh the Supabase auth session on each request so server components and
- * actions see a valid token. Reads/writes session cookies via the request and
- * response (middleware can't use next/headers cookies()).
- *
- * @param {import('next/server').NextRequest} request
- */
-export async function middleware(request) {
-  let response = NextResponse.next({ request });
-
-  const url = process.env.NEXT_PUBLIC_SUPABASE_URL;
-  const anonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
-  if (!url || !anonKey) return response; // no auth configured yet
-
-  const supabase = createServerClient(url, anonKey, {
-    cookies: {
-      getAll() {
-        return request.cookies.getAll();
-      },
-      setAll(cookiesToSet) {
-        for (const { name, value } of cookiesToSet) {
-          request.cookies.set(name, value);
-        }
-        response = NextResponse.next({ request });
-        for (const { name, value, options } of cookiesToSet) {
-          response.cookies.set(name, value, options);
-        }
-      },
-    },
-  });
-
-  await supabase.auth.getUser();
-  return response;
-}
-
-export const config = {
-  matcher: ["/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|ico)$).*)"],
-};
diff --git a/package-lock.json b/package-lock.json
index 190bd9a..3429228 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,8 +8,8 @@
       "name": "llmapikey",
       "version": "0.1.0",
       "dependencies": {
-        "@supabase/ssr": "^0.5.2",
-        "@supabase/supabase-js": "^2.45.4",
+        "arctic": "^3.7.0",
+        "jose": "^6.2.3",
         "next": "^15.1.6",
         "postgres": "^3.4.5",
         "react": "^19.0.0",
@@ -1001,6 +1001,52 @@
         "node": ">=12.4.0"
       }
     },
+    "node_modules/@oslojs/asn1": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@oslojs/asn1/-/asn1-1.0.0.tgz",
+      "integrity": "sha512-zw/wn0sj0j0QKbIXfIlnEcTviaCzYOY3V5rAyjR6YtOByFtJiT574+8p9Wlach0lZH9fddD4yb9laEAIl4vXQA==",
+      "license": "MIT",
+      "dependencies": {
+        "@oslojs/binary": "1.0.0"
+      }
+    },
+    "node_modules/@oslojs/binary": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@oslojs/binary/-/binary-1.0.0.tgz",
+      "integrity": "sha512-9RCU6OwXU6p67H4NODbuxv2S3eenuQ4/WFLrsq+K/k682xrznH5EVWA7N4VFk9VYVcbFtKqur5YQQZc0ySGhsQ==",
+      "license": "MIT"
+    },
+    "node_modules/@oslojs/crypto": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/@oslojs/crypto/-/crypto-1.0.1.tgz",
+      "integrity": "sha512-7n08G8nWjAr/Yu3vu9zzrd0L9XnrJfpMioQcvCMxBIiF5orECHe5/3J0jmXRVvgfqMm/+4oxlQ+Sq39COYLcNQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@oslojs/asn1": "1.0.0",
+        "@oslojs/binary": "1.0.0"
+      }
+    },
+    "node_modules/@oslojs/encoding": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/@oslojs/encoding/-/encoding-1.1.0.tgz",
+      "integrity": "sha512-70wQhgYmndg4GCPxPPxPGevRKqTIJ2Nh4OkiMWmDAVYsTQ+Ta7Sq+rPevXyXGdzr30/qZBnyOalCszoMxlyldQ==",
+      "license": "MIT"
+    },
+    "node_modules/@oslojs/jwt": {
+      "version": "0.2.0",
+      "resolved": "https://registry.npmjs.org/@oslojs/jwt/-/jwt-0.2.0.tgz",
+      "integrity": "sha512-bLE7BtHrURedCn4Mco3ma9L4Y1GR2SMBuIvjWr7rmQ4/W/4Jy70TIAgZ+0nIlk0xHz1vNP8x8DCns45Sb2XRbg==",
+      "license": "MIT",
+      "dependencies": {
+        "@oslojs/encoding": "0.4.1"
+      }
+    },
+    "node_modules/@oslojs/jwt/node_modules/@oslojs/encoding": {
+      "version": "0.4.1",
+      "resolved": "https://registry.npmjs.org/@oslojs/encoding/-/encoding-0.4.1.tgz",
+      "integrity": "sha512-hkjo6MuIK/kQR5CrGNdAPZhS01ZCXuWDRJ187zh6qqF2+yMHZpD9fAYpX8q2bOO6Ryhl3XpCT6kUX76N8hhm4Q==",
+      "license": "MIT"
+    },
     "node_modules/@rtsao/scc": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/@rtsao/scc/-/scc-1.1.0.tgz",
@@ -1015,103 +1061,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/@supabase/auth-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/auth-js/-/auth-js-2.108.1.tgz",
-      "integrity": "sha512-Lle5rKU8f9LF3K5dDd8Or8mkkG+ptzRZZWKPVMm9B9UuovH65Ss2+iFnQqRsCqaGouvJEcTWyl0cj2riNrrDLQ==",
-      "license": "MIT",
-      "dependencies": {
-        "tslib": "2.8.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@supabase/functions-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/functions-js/-/functions-js-2.108.1.tgz",
-      "integrity": "sha512-fxBRW/A4IG7ADQztVt0NaEy5ysiO1WJ2pbldsnBchrkHuyepX0Krek9qA9T4gUQBVVTCE9Ea4pdsM5hfn3nc4A==",
-      "license": "MIT",
-      "dependencies": {
-        "tslib": "2.8.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@supabase/phoenix": {
-      "version": "0.4.2",
-      "resolved": "https://registry.npmjs.org/@supabase/phoenix/-/phoenix-0.4.2.tgz",
-      "integrity": "sha512-YSAGnmDAfuleFCVt3CeurQZAhxRfXWeZIIkwp7NhYzQ1UwW6ePSnzsFAiUm/mbCkfoCf70QQHKW/K6RKh52a4A==",
-      "license": "MIT"
-    },
-    "node_modules/@supabase/postgrest-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/postgrest-js/-/postgrest-js-2.108.1.tgz",
-      "integrity": "sha512-9lj2MCPPMgSTaJ5y+amnhb3TWPtMFVlbDn2hmX/VV91xQU4j0AauwfMaBErHBJ+zzsSwjc0jLU+zLIZFLQzfig==",
-      "license": "MIT",
-      "dependencies": {
-        "tslib": "2.8.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@supabase/realtime-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/realtime-js/-/realtime-js-2.108.1.tgz",
-      "integrity": "sha512-mHGGqOjwd1XTydcoffUqEMsbFQHUi6A3uhQ0EXr3iqzpLqItxKA9nbN6gIQxrZ7JRRnuUe/iOFPUkYV9Tdc5lg==",
-      "license": "MIT",
-      "dependencies": {
-        "@supabase/phoenix": "^0.4.2",
-        "tslib": "2.8.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@supabase/ssr": {
-      "version": "0.5.2",
-      "resolved": "https://registry.npmjs.org/@supabase/ssr/-/ssr-0.5.2.tgz",
-      "integrity": "sha512-n3plRhr2Bs8Xun1o4S3k1CDv17iH5QY9YcoEvXX3bxV1/5XSasA0mNXYycFmADIdtdE6BG9MRjP5CGIs8qxC8A==",
-      "license": "MIT",
-      "dependencies": {
-        "@types/cookie": "^0.6.0",
-        "cookie": "^0.7.0"
-      },
-      "peerDependencies": {
-        "@supabase/supabase-js": "^2.43.4"
-      }
-    },
-    "node_modules/@supabase/storage-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/storage-js/-/storage-js-2.108.1.tgz",
-      "integrity": "sha512-Er0SGGt85iT6ye+SSh98Az6L2CesoZJuyzEZYH2oBOAnIxa9Nn4CtwUC3veGxYggoT56X+3tVuuQeDBP8kR8sg==",
-      "license": "MIT",
-      "dependencies": {
-        "iceberg-js": "^0.8.1",
-        "tslib": "2.8.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
-    "node_modules/@supabase/supabase-js": {
-      "version": "2.108.1",
-      "resolved": "https://registry.npmjs.org/@supabase/supabase-js/-/supabase-js-2.108.1.tgz",
-      "integrity": "sha512-V/1hRKLSCJ0zEL+9QFRBUtivvePfOsaAYQmC0HhFNSHC2F3xFs4jSF3YhkLmzex6E4V4FGvmBDOP72D/53NnZA==",
-      "license": "MIT",
-      "dependencies": {
-        "@supabase/auth-js": "2.108.1",
-        "@supabase/functions-js": "2.108.1",
-        "@supabase/postgrest-js": "2.108.1",
-        "@supabase/realtime-js": "2.108.1",
-        "@supabase/storage-js": "2.108.1"
-      },
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
     "node_modules/@swc/helpers": {
       "version": "0.5.15",
       "resolved": "https://registry.npmjs.org/@swc/helpers/-/helpers-0.5.15.tgz",
@@ -1132,12 +1081,6 @@
         "tslib": "^2.4.0"
       }
     },
-    "node_modules/@types/cookie": {
-      "version": "0.6.0",
-      "resolved": "https://registry.npmjs.org/@types/cookie/-/cookie-0.6.0.tgz",
-      "integrity": "sha512-4Kh9a6B2bQciAhf7FSuMRRkUWecJgJu9nPnx3yzpsfXX/c50REIqpHY4C82bXP90qrLtXtkDxTZosYO3UpOwlA==",
-      "license": "MIT"
-    },
     "node_modules/@types/estree": {
       "version": "1.0.9",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.9.tgz",
@@ -1851,6 +1794,17 @@
         "url": "https://github.com/chalk/ansi-styles?sponsor=1"
       }
     },
+    "node_modules/arctic": {
+      "version": "3.7.0",
+      "resolved": "https://registry.npmjs.org/arctic/-/arctic-3.7.0.tgz",
+      "integrity": "sha512-ZMQ+f6VazDgUJOd+qNV+H7GohNSYal1mVjm5kEaZfE2Ifb7Ss70w+Q7xpJC87qZDkMZIXYf0pTIYZA0OPasSbw==",
+      "license": "MIT",
+      "dependencies": {
+        "@oslojs/crypto": "1.0.1",
+        "@oslojs/encoding": "1.1.0",
+        "@oslojs/jwt": "0.2.0"
+      }
+    },
     "node_modules/argparse": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/argparse/-/argparse-2.0.1.tgz",
@@ -2242,15 +2196,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/cookie": {
-      "version": "0.7.2",
-      "resolved": "https://registry.npmjs.org/cookie/-/cookie-0.7.2.tgz",
-      "integrity": "sha512-yki5XnKuf750l50uGTllt6kKILY4nQ1eNIQatoXEByZ5dWgnKqbnqmTrBE5B4N7lrMJKQ2ytWMiTO2o0v6Ew/w==",
-      "license": "MIT",
-      "engines": {
-        "node": ">= 0.6"
-      }
-    },
     "node_modules/cross-spawn": {
       "version": "7.0.6",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
@@ -3445,15 +3390,6 @@
         "node": ">= 0.4"
       }
     },
-    "node_modules/iceberg-js": {
-      "version": "0.8.1",
-      "resolved": "https://registry.npmjs.org/iceberg-js/-/iceberg-js-0.8.1.tgz",
-      "integrity": "sha512-1dhVQZXhcHje7798IVM+xoo/1ZdVfzOMIc8/rgVSijRK38EDqOJoGula9N/8ZI5RD8QTxNQtK/Gozpr+qUqRRA==",
-      "license": "MIT",
-      "engines": {
-        "node": ">=20.0.0"
-      }
-    },
     "node_modules/ignore": {
       "version": "5.3.2",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.2.tgz",
@@ -3956,6 +3892,15 @@
         "node": ">= 0.4"
       }
     },
+    "node_modules/jose": {
+      "version": "6.2.3",
+      "resolved": "https://registry.npmjs.org/jose/-/jose-6.2.3.tgz",
+      "integrity": "sha512-YYVDInQKFJfR/xa3ojUTl8c2KoTwiL1R5Wg9YCydwH0x0B9grbzlg5HC7mMjCtUJjbQ/YnGEZIhI5tCgfTb4Hw==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/panva"
+      }
+    },
     "node_modules/js-tokens": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-4.0.0.tgz",
diff --git a/package.json b/package.json
index 4599a32..586b212 100644
--- a/package.json
+++ b/package.json
@@ -11,8 +11,8 @@
     "test": "node --test \"tests/*.test.js\""
   },
   "dependencies": {
-    "@supabase/ssr": "^0.5.2",
-    "@supabase/supabase-js": "^2.45.4",
+    "arctic": "^3.7.0",
+    "jose": "^6.2.3",
     "next": "^15.1.6",
     "postgres": "^3.4.5",
     "react": "^19.0.0",
diff --git a/plans/260614-1050-switch-to-app-native-github-oauth/phase-01-session-oauth-foundation.md b/plans/260614-1050-switch-to-app-native-github-oauth/phase-01-session-oauth-foundation.md
new file mode 100644
index 0000000..e401a89
--- /dev/null
+++ b/plans/260614-1050-switch-to-app-native-github-oauth/phase-01-session-oauth-foundation.md
@@ -0,0 +1,85 @@
+---
+phase: 1
+title: "Session & OAuth Foundation"
+status: pending
+priority: P1
+effort: "3h"
+dependencies: []
+---
+
+# Phase 1: Session & OAuth Foundation
+
+## Overview
+Add the OAuth client + stateless session primitives the new flow stands on, with no
+behavior change yet (current Supabase path keeps working). Pure additive phase.
+
+## Requirements
+- Functional: a session module that signs/verifies a JWT cookie carrying
+  `{ githubUserId, githubUsername }`; a GitHub OAuth client factory (Arctic).
+- Non-functional: secrets server-only; cookie httpOnly+Secure+SameSite=Lax; HS256 with
+  a ≥32-byte secret; numeric-`provider_id` invariant preserved.
+
+## Architecture
+- **Session (`lib/auth/session.js`)** — jose `SignJWT`/`jwtVerify`. Cookie name
+  `llmapikey_session`. Exposes `createSession(identity)`, `readSession()` (returns
+  `{ githubUserId, githubUsername } | null`, swallows verify errors), `clearSession()`,
+  and cookie attribute constants. Uses `next/headers` `cookies()`.
+- **OAuth client (`lib/auth/github-oauth.js`)** — wraps Arctic `GitHub(clientId,
+  clientSecret, `${origin}/auth/callback`)`. Exposes a `getGithubOAuth(origin)` factory
+  (origin-derived callback, no callback env) + the OAuth scope constant `["read:user"]`.
+- **Sanitizer (`lib/auth/sanitize-next.js`)** — extracted from the current callback route
+  so both `/auth/login` and `/auth/callback` share one open-redirect guard (same-origin
+  relative paths only; default `/dashboard`).
+- Secrets read from env: `GITHUB_OAUTH_CLIENT_ID`, `GITHUB_OAUTH_CLIENT_SECRET`,
+  `AUTH_SESSION_SECRET`. All server-only (no `NEXT_PUBLIC_`).
+
+## Related Code Files
+- Create: `lib/auth/session.js`
+- Create: `lib/auth/github-oauth.js`
+- Create: `lib/auth/sanitize-next.js`
+- Create: `tests/session-roundtrip.test.js`
+- Modify: `package.json` (add `arctic`, `jose` — pin Arctic major: API differs across majors)
+- Modify: `.env.example` (add the 3 new server-only vars; leave Supabase vars for now)
+
+## Implementation Steps
+1. `npm install arctic jose` (runtime deps).
+2. `lib/auth/session.js`:
+   - `import "server-only";`
+   - `const secret = () => new TextEncoder().encode(process.env.AUTH_SESSION_SECRET)` —
+     throw if unset/<32 bytes.
+   - `createSession({ githubUserId, githubUsername })`: `new SignJWT({ login })
+     .setProtectedHeader({alg:'HS256'}).setSubject(githubUserId).setIssuedAt()
+     .setExpirationTime('7d').sign(secret())`, then `cookies().set(NAME, jwt, ATTRS)`.
+   - `readSession()`: read cookie → `jwtVerify` → re-assert `/^\d+$/` on `sub` →
+     return `{ githubUserId: payload.sub, githubUsername: payload.login }`; any
+     throw/missing → `null`.
+   - `clearSession()`: `cookies().delete(NAME)`.
+   - `ATTRS = { httpOnly:true, secure:true, sameSite:'lax', path:'/', maxAge: 60*60*24*7 }`.
+3. `lib/auth/github-oauth.js`: `getGithubOAuth(origin)` returns
+   `new GitHub(id, secret, `${origin}/auth/callback`)` (throw if id/secret unset);
+   export `GITHUB_SCOPES`. Also create `lib/auth/sanitize-next.js` exporting `sanitizeNext`
+   (moved from the callback route).
+4. `tests/session-roundtrip.test.js` (node:test): set `AUTH_SESSION_SECRET`, sign an
+   identity → verify roundtrip; assert tampered token → null; assert non-numeric `sub`
+   rejected; assert expired token → null.
+5. Update `.env.example` with the 3 new vars + comments (server-only).
+6. `npm run build` — must compile clean.
+
+## Success Criteria
+- [ ] `arctic` + `jose` in `package.json`; `npm install` clean.
+- [ ] `lib/auth/session.js` and `lib/auth/github-oauth.js` compile; `server-only` guarded.
+- [ ] `npm test` passes including new session roundtrip + tamper/expiry/non-numeric tests.
+- [ ] No behavior change — existing Supabase auth still functions (nothing wired yet).
+
+## Risk Assessment
+- **Weak/missing `AUTH_SESSION_SECRET`** → `secret()` throws (config error), so a
+  misconfig 500s any page that reads identity (incl. public landing). Intended fail-fast.
+  Note the split: `readSession` swallows *token* errors (tamper/expiry → null) but lets
+  *config* errors propagate. Document 32-byte requirement.
+- **jose ESM** — project is `"type":"module"`, so native import is fine.
+- **SameSite choice** — `Lax` required so the cookie rides the top-level GET redirect back
+  from GitHub; `Strict` would drop it. Documented inline.
+
+## Security Considerations
+- Secrets never prefixed `NEXT_PUBLIC_`; `server-only` import guard on both modules.
+- Preserve numeric-`provider_id` assertion at both mint and read (defense in depth).
diff --git a/plans/260614-1050-switch-to-app-native-github-oauth/phase-02-oauth-routes-identity-swap.md b/plans/260614-1050-switch-to-app-native-github-oauth/phase-02-oauth-routes-identity-swap.md
new file mode 100644
index 0000000..3d5688a
--- /dev/null
+++ b/plans/260614-1050-switch-to-app-native-github-oauth/phase-02-oauth-routes-identity-swap.md
@@ -0,0 +1,105 @@
+---
+phase: 2
+title: "OAuth Routes & Identity Swap"
+status: pending
+priority: P1
+effort: "4h"
+dependencies: [1]
+---
+
+# Phase 2: OAuth Routes & Identity Swap
+
+## Overview
+Wire the new flow end-to-end and flip the identity source from Supabase to the signed
+cookie. After this phase the app authenticates via its own GitHub OAuth; Supabase auth
+code is no longer exercised (deleted in Phase 3).
+
+## Requirements
+- Functional: `/auth/login` initiates GitHub OAuth (state cookie + redirect);
+  `/auth/callback` validates state, exchanges code, fetches `/user`, mints session;
+  `/auth/sign-out` clears session; `getCurrentGithubIdentity()` reads the cookie.
+- Non-functional: open-redirect safe (`next` sanitized); state single-use; identity
+  contract `{ githubUserId, githubUsername }` unchanged for all callers.
+
+## Architecture
+Flow: button → `GET /auth/login?next=/dashboard` (server: create state, set
+`oauth_state` httpOnly cookie, 302 to GitHub authorize URL) → GitHub consent → `GET
+/auth/callback?code&state` (verify state vs cookie, Arctic `validateAuthorizationCode`,
+`GET https://api.github.com/user` with bearer → `{ id, login }` → `createSession` →
+clear state cookie → 302 to sanitized `next`).
+
+`getCurrentGithubIdentity()` now delegates to `readSession()` — same return shape, so
+`lib/auth/admin-allowlist.js`, `app/actions/generate-key.js`, `app/actions/admin-keys.js`,
+`app/dashboard/page.js`, `app/admin/page.js` need **no changes**.
+
+**Exception — `components/site-header.js`** currently calls `createServerAuthClient()`
+directly (NOT `getCurrentGithubIdentity()`), so it MUST be migrated: replace the Supabase
+`getUser()` block with `const identity = await getCurrentGithubIdentity()` and use
+`identity?.githubUsername`.
+
+Middleware no longer refreshes a Supabase session (stateless JWT verified on demand). Keep
+a minimal/no-op middleware or remove the file; remove the `@supabase/ssr` import either way.
+
+## Related Code Files
+- Create: `app/auth/login/route.js`
+- Modify: `app/auth/callback/route.js` (rewrite: state + Arctic + `/user` + session; import shared `sanitizeNext`)
+- Modify: `app/auth/sign-out/route.js` (keep `POST` + `{status:303}`; clear cookie instead of `supabase.auth.signOut()`)
+- Modify: `lib/auth/current-github-identity.js` (read `readSession()`; keep numeric assert + JSDoc)
+- Modify: `components/sign-in-with-github-button.js` (anchor to `/auth/login?next=…`; drop browser supabase client)
+- Modify: `components/site-header.js` (use `getCurrentGithubIdentity()`; drop Supabase client)
+- Modify: `middleware.js` (delete file — stateless JWT needs no refresh)
+
+## Implementation Steps
+1. `app/auth/login/route.js` (GET): derive `origin` from request; `next = sanitizeNext(query.next)`;
+   `const state = generateState()` (Arctic); `oauth = getGithubOAuth(origin)`;
+   `url = oauth.createAuthorizationURL(state, GITHUB_SCOPES)`; set `oauth_state` cookie
+   (httpOnly, secure, lax, maxAge 600) AND `oauth_next` cookie (same attrs) via the
+   `cookies()` store; `return NextResponse.redirect(url)`. (Cookies set via `cookies()`
+   attach to the redirect response in route handlers.)
+2. Rewrite `app/auth/callback/route.js`:
+   - read `code`, `state`; read `oauth_state` cookie; if mismatch/missing → redirect `/?auth_error=1`.
+   - `oauth = getGithubOAuth(origin)` (same origin as login → matching redirect_uri);
+     `tokens = await oauth.validateAuthorizationCode(code)`; `access = tokens.accessToken()`.
+   - `fetch('https://api.github.com/user', { headers:{ Authorization:`Bearer ${access}`,
+     'User-Agent':'llmapikey' }})` → `{ id, login }`; coerce `id` to string, assert numeric.
+   - `await createSession({ githubUserId:String(id), githubUsername:login })`.
+   - read `next` from `oauth_next` cookie → `sanitizeNext`; clear `oauth_state` + `oauth_next`;
+     redirect to `${origin}${next}`. Discard the access token (not persisted).
+3. `app/auth/sign-out/route.js` (keep `POST`): `await clearSession(); return
+   NextResponse.redirect(new URL('/', request.url), { status: 303 })`. Remove Supabase import.
+   (Caller is a `method="post"` form in `site-header.js`; 303 turns it into a GET.)
+4. `lib/auth/current-github-identity.js`: replace Supabase body with `return await
+   readSession();` Keep the `GithubIdentity` typedef + numeric invariant note. Drop the
+   Supabase import.
+5. `components/sign-in-with-github-button.js`: replace `signInWithOAuth` with a plain
+   anchor/`<a href={'/auth/login?next='+encodeURIComponent(next)}>` (or `router.push`).
+   Remove `createBrowserSupabaseClient` import. Keep loading UX minimal.
+6. `components/site-header.js`: replace `createServerAuthClient()`/`getUser()` with
+   `const identity = await getCurrentGithubIdentity()`; `username = identity?.githubUsername`.
+   Keep the try/catch (DB/config unconfigured → signed-out header). Drop Supabase import.
+7. `middleware.js`: delete the file entirely (stateless JWT verified on demand; pages
+   self-gate via `getCurrentGithubIdentity()`). KISS.
+8. `npm run build`; manual local check deferred to Phase 3 (needs real GitHub creds).
+
+## Success Criteria
+- [ ] `/auth/login` 302s to `github.com/login/oauth/authorize` with `state` + `read:user`.
+- [ ] `/auth/callback` with valid code sets `llmapikey_session` cookie and redirects to `next`.
+- [ ] State mismatch/missing → redirect to `/?auth_error=1`, no session set.
+- [ ] `getCurrentGithubIdentity()` returns the same shape from the cookie; admin/dashboard/
+      generate-key compile and behave unchanged.
+- [ ] No remaining `@supabase/ssr` import in `middleware.js`, sign-in button, or auth routes.
+- [ ] `npm run build` clean.
+
+## Risk Assessment
+- **State/next cookie coupling** — keep state and next in httpOnly cookies; never trust
+  query `next` without `sanitizeNext`. Mitigation: reuse existing sanitizer.
+- **GitHub `/user` rate/UA** — GitHub requires a `User-Agent` header; omitting it 403s.
+- **Cookie not set on redirect** — set cookies on the `NextResponse` (route handlers can
+  write); verify `Set-Cookie` present on the 302.
+- **Email/primary not needed** — we only read `id`+`login`; no extra `user:email` scope.
+
+## Security Considerations
+- CSRF via single-use `state` (httpOnly, 10-min TTL), compared server-side.
+- Open-redirect prevented by `sanitizeNext` (same-origin relative only).
+- Access token never stored or logged; lives only inside the callback request.
+- Session cookie httpOnly+Secure+Lax; numeric `provider_id` re-asserted before minting.
diff --git a/plans/260614-1050-switch-to-app-native-github-oauth/phase-03-cleanup-config-deploy.md b/plans/260614-1050-switch-to-app-native-github-oauth/phase-03-cleanup-config-deploy.md
new file mode 100644
index 0000000..b11aa77
--- /dev/null
+++ b/plans/260614-1050-switch-to-app-native-github-oauth/phase-03-cleanup-config-deploy.md
@@ -0,0 +1,85 @@
+---
+phase: 3
+title: "Cleanup Config & Deploy"
+status: pending
+priority: P1
+effort: "2h"
+dependencies: [2]
+---
+
+# Phase 3: Cleanup Config & Deploy
+
+## Overview
+Remove the dead Supabase-auth surface, reconcile config/docs/tests, provision the GitHub
+OAuth App + Vercel env, and ship. End state: app authenticates entirely on its own; Supabase
+is Postgres-only.
+
+## Requirements
+- Functional: no Supabase auth code/deps remain; live GitHub sign-in works end-to-end.
+- Non-functional: build+tests green; secrets server-only; docs match reality.
+
+## Architecture
+Deletes `lib/supabase/*` (auth clients) and the `@supabase/*` deps. The only Supabase
+touchpoint left is `POSTGRES_URL` (DB), consumed by `lib/db/postgres-client.js` — unchanged.
+GitHub OAuth App callback now points at the **app** (`/auth/callback`), not Supabase.
+
+## Related Code Files
+- Delete: `lib/supabase/server-client.js`, `lib/supabase/browser-client.js` (whole `lib/supabase/`)
+- Delete: `tests/rls-deny-all.test.js` (top-level imports `@supabase/supabase-js`; would fail to load once the dep is removed — DECIDED: delete)
+- Modify: `package.json` (remove `@supabase/ssr`, `@supabase/supabase-js`)
+- Modify: `.env.example` (remove `NEXT_PUBLIC_SUPABASE_URL`/`_ANON_KEY`; finalize new vars)
+- Modify: `README.md` (rewrite auth/setup: GitHub OAuth App callback → app domain, new env table)
+
+## Implementation Steps
+1. Delete `lib/supabase/` (both clients). Grep-confirm zero remaining imports of
+   `@/lib/supabase/*`, `@supabase/ssr`, `@supabase/supabase-js` across `app/ lib/ middleware.js`.
+2. `npm uninstall @supabase/ssr @supabase/supabase-js`.
+3. Delete `tests/rls-deny-all.test.js` (DECIDED). Its top-level `import { createClient }
+   from "@supabase/supabase-js"` would throw module-not-found once the dep is removed, even
+   though the test self-skips. Isolation stays structural (unexposed schema + direct PG +
+   deny-all RLS); add a README note.
+4. `.env.example`: drop the two `NEXT_PUBLIC_SUPABASE_*` lines; add `GITHUB_OAUTH_CLIENT_ID`,
+   `GITHUB_OAUTH_CLIENT_SECRET`, `AUTH_SESSION_SECRET` (callback is origin-derived, no env);
+   keep `POSTGRES_URL`, `OPENROUTER_MANAGEMENT_KEY`, caps, `ADMIN_GITHUB_USER_IDS`.
+5. `README.md`: rewrite Stack + Setup auth steps — GitHub OAuth App with callback
+   `https://llmapikey.vercel.app/auth/callback`; remove Supabase Auth provider setup; note
+   Supabase = Postgres only. Update Architecture "Server-only secrets" list.
+6. **GitHub OAuth App**: create (or repoint) with Authorization callback
+   `https://llmapikey.vercel.app/auth/callback`; copy Client ID + Secret.
+7. **Vercel env** (Production): add `GITHUB_OAUTH_CLIENT_ID`, `GITHUB_OAUTH_CLIENT_SECRET`,
+   `AUTH_SESSION_SECRET` (`openssl rand -base64 48`). Remove `NEXT_PUBLIC_SUPABASE_URL`/
+   `_ANON_KEY`. (Callback is origin-derived; sign-in works only on the canonical domain
+   registered in the OAuth App — non-canonical hosts fail at GitHub. Accepted.)
+8. `npm run build && npm test` — all green.
+9. `vercel deploy --prod --yes`; smoke-test: `/` 200, `/auth/login` 302→github, full
+   sign-in lands on `/dashboard`, `/admin` 404 anon, sign-out clears cookie.
+
+## Success Criteria
+- [ ] No `@supabase/*` deps in `package.json`; `lib/supabase/` gone; zero stale imports.
+- [ ] `.env.example` + `README.md` reflect app-native OAuth; no Supabase-auth references.
+- [ ] `npm run build` + `npm test` pass.
+- [ ] Live: GitHub sign-in completes → `/dashboard`; sign-out works; `/admin` 404 for anon.
+- [ ] Vercel has the 3 new vars; Supabase anon vars removed.
+
+## Risk Assessment
+- **Cutover invalidates existing Supabase sessions** — users re-login once. Acceptable
+  (gated/low usage). Communicate if needed.
+- **Forgot to repoint GitHub OAuth callback** → `redirect_uri mismatch` at GitHub.
+  Mitigation: step 6 before deploy; verify exact string.
+- **`AUTH_SESSION_SECRET` differs Preview vs Prod** — fine (separate session domains); just
+  ensure each is set or `readSession` throws.
+- **Removing rls test** reduces explicit coverage of schema isolation — mitigate by a note
+  in README that isolation is structural (unexposed schema + direct PG).
+
+## Security Considerations
+- Confirm no secret ever carries `NEXT_PUBLIC_`.
+- Verify deployed `Set-Cookie` flags (httpOnly, Secure, SameSite=Lax) via curl.
+- Keep `ADMIN_GITHUB_USER_IDS` fail-closed behavior intact (unchanged identity contract).
+
+## Resolved Decisions
+1. **rls-deny-all test** — DELETED (top-level supabase-js import breaks once dep removed; isolation is structural).
+2. **Redirect URI** — origin-derived (`${origin}/auth/callback`), no callback env; sign-in works only on the canonical registered domain (deployment-hash/preview hosts fail at GitHub — accepted).
+3. **middleware.js** — DELETED entirely (stateless JWT, pages self-gate).
+
+## Open Questions
+1. **GitHub OAuth App** — register a fresh app dedicated to llmapikey (recommended) vs reuse existing? (deploy-time, not code)
diff --git a/plans/260614-1050-switch-to-app-native-github-oauth/plan.md b/plans/260614-1050-switch-to-app-native-github-oauth/plan.md
new file mode 100644
index 0000000..99d1a49
--- /dev/null
+++ b/plans/260614-1050-switch-to-app-native-github-oauth/plan.md
@@ -0,0 +1,59 @@
+---
+title: "Switch auth: Supabase Auth → app-native GitHub OAuth (Arctic + jose)"
+description: "Replace Supabase Auth (GitHub provider) with self-contained GitHub OAuth handled in the Next.js app. Stateless signed-cookie session. Removes shared-Supabase coupling; Supabase becomes Postgres-only."
+status: in-progress
+priority: P2
+branch: "master"
+tags: [auth, oauth, github, security, nextjs]
+blockedBy: []
+blocks: []
+created: "2026-06-14T03:52:45.628Z"
+createdBy: "ck:plan"
+source: skill
+---
+
+# Switch auth: Supabase Auth → app-native GitHub OAuth (Arctic + jose)
+
+## Overview
+
+Today auth is brokered by Supabase (GitHub provider → Supabase `/auth/v1/callback` →
+app). Supabase is used **only** for auth — data is direct Postgres to the unexposed
+`llmapikey` schema. This plan replaces Supabase Auth with GitHub OAuth handled in-app
+(GitHub → `llmapikey.vercel.app/auth/callback`), using **Arctic** for the OAuth2 dance
+and **jose** for a stateless signed-cookie session. Net effect: per-app user isolation,
+one fewer redirect hop, no shared `auth.users`/JWT/rate-limit pool, and Supabase
+downgraded to "just the DB host".
+
+Identity contract is preserved: `getCurrentGithubIdentity()` keeps returning
+`{ githubUserId, githubUsername }` (numeric `provider_id` anchor), so admin allowlist,
+key minting, and dashboard are untouched downstream.
+
+## Phases
+
+| Phase | Name | Status |
+|-------|------|--------|
+| 1 | [Session & OAuth Foundation](./phase-01-session-oauth-foundation.md) | Done |
+| 2 | [OAuth Routes & Identity Swap](./phase-02-oauth-routes-identity-swap.md) | Done |
+| 3 | [Cleanup Config & Deploy](./phase-03-cleanup-config-deploy.md) | Code done; deploy steps (OAuth App, Vercel env, prod deploy) pending |
+
+## Key Decisions
+
+- **Stateless session** — signed JWT (HS256, jose) in an httpOnly cookie. No DB session
+  table (app has no user table; identity = `provider_id` + login). Re-login on expiry.
+- **No token storage** — `read:user` scope only; fetch `/user` once at callback, derive
+  id+login, discard the access token. Nothing to refresh.
+- **CSRF** — Arctic `state` stored in a short-lived httpOnly cookie, verified at callback.
+- **Origin-derived redirect URI** — `${origin}/auth/callback`, built from the request
+  origin (no callback env). GitHub validates it against the OAuth App's single registered
+  callback, so sign-in works only when the app is reached on its canonical registered host;
+  non-canonical hosts (Vercel deployment-hash / preview URLs) fail at GitHub — accepted, we
+  link only the canonical domain. Login + callback pass the same origin so `redirect_uri`
+  matches across authorize + token-exchange. The post-login `next` redirect also uses origin.
+
+## Dependencies
+
+- **Supersedes** the auth design in `project:260613-1144-openrouter-key-giveaway-website`
+  (that plan is effectively built/deployed; only its Supabase-auth choice is replaced here).
+  No hard block — the live site keeps working through cutover.
+- **No impact** on `project:260613-2033-admin-management-crud` (completed) — admin authz
+  reads the unchanged `getCurrentGithubIdentity()` contract.
diff --git a/tests/rls-deny-all.test.js b/tests/rls-deny-all.test.js
deleted file mode 100644
index 5580e3c..0000000
--- a/tests/rls-deny-all.test.js
+++ /dev/null
@@ -1,35 +0,0 @@
-import assert from "node:assert/strict";
-import { test } from "node:test";
-
-import { createClient } from "@supabase/supabase-js";
-
-const url = process.env.NEXT_PUBLIC_SUPABASE_URL;
-const anonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
-
-/**
- * Real-Supabase verification: the anon role must NOT be able to read api_keys.
- * Because `llmapikey` is unexposed to PostgREST, the anon client should get a
- * schema/permission error (or, defensively, zero rows) — never real data.
- *
- * Skips when Supabase env is absent so `npm test` passes in CI/local without
- * credentials. Run against a real project to actually exercise the invariant.
- */
-test(
-  "anon client cannot read llmapikey.api_keys",
-  { skip: !url || !anonKey ? "Supabase env not set" : false },
-  async () => {
-    const supabase = createClient(url, anonKey, {
-      auth: { persistSession: false },
-    });
-    const { data, error } = await supabase
-      .schema("llmapikey")
-      .from("api_keys")
-      .select("id");
-
-    // The schema is unexposed to PostgREST, so the anon client MUST get an
-    // error (e.g. PGRST106). An empty array is NOT acceptable — that would mean
-    // the schema became reachable, just with no rows visible.
-    assert.notEqual(error, null, "anon must receive a hard error, not a result set");
-    assert.equal(data, null, "anon must not receive any data array");
-  },
-);
diff --git a/tests/session-roundtrip.test.js b/tests/session-roundtrip.test.js
new file mode 100644
index 0000000..12ef079
--- /dev/null
+++ b/tests/session-roundtrip.test.js
@@ -0,0 +1,59 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+import {
+  encodeSecret,
+  signSessionToken,
+  verifySessionToken,
+} from "../lib/auth/session-token.js";
+
+const SECRET = encodeSecret("x".repeat(48));
+const IDENTITY = { githubUserId: "12345", githubUsername: "octocat" };
+
+test("session token round-trips identity", async () => {
+  const token = await signSessionToken(IDENTITY, SECRET);
+  const decoded = await verifySessionToken(token, SECRET);
+  assert.deepEqual(decoded, IDENTITY);
+});
+
+test("tampered token verifies to null", async () => {
+  const token = await signSessionToken(IDENTITY, SECRET);
+  const tampered = token.slice(0, -2) + (token.endsWith("a") ? "bb" : "aa");
+  assert.equal(await verifySessionToken(tampered, SECRET), null);
+});
+
+test("token signed with a different secret verifies to null", async () => {
+  const token = await signSessionToken(IDENTITY, SECRET);
+  const otherSecret = encodeSecret("y".repeat(48));
+  assert.equal(await verifySessionToken(token, otherSecret), null);
+});
+
+test("non-numeric subject is rejected", async () => {
+  const token = await signSessionToken(
+    { githubUserId: "octocat", githubUsername: "octocat" },
+    SECRET,
+  );
+  assert.equal(await verifySessionToken(token, SECRET), null);
+});
+
+test("expired token verifies to null", async () => {
+  const { SignJWT } = await import("jose");
+  const expired = await new SignJWT({ login: "octocat" })
+    .setProtectedHeader({ alg: "HS256" })
+    .setSubject("12345")
+    .setIssuedAt(0)
+    .setExpirationTime(1) // epoch+1s — long past
+    .sign(SECRET);
+  assert.equal(await verifySessionToken(expired, SECRET), null);
+});
+
+test("missing token verifies to null", async () => {
+  assert.equal(await verifySessionToken(undefined, SECRET), null);
+  assert.equal(await verifySessionToken("", SECRET), null);
+});
+
+test("encodeSecret rejects short/missing secrets", () => {
+  assert.throws(() => encodeSecret(undefined));
+  assert.throws(() => encodeSecret("tooshort"));
+  assert.doesNotThrow(() => encodeSecret("z".repeat(32)));
+});