e6a7cae7e1 fix(apscheduler): prevent memory leaks from jitter and frequent job intervals (#15846)
* fix(apscheduler): prevent memory leaks from jitter and frequent job intervals

Fixes critical memory leak in APScheduler that causes 35GB+ memory allocations
during proxy startup and operation. The leak was identified through Memray
analysis showing massive allocations in normalize() and _apply_jitter()
functions.

Key changes:
1. Remove jitter parameters from all scheduled jobs - jitter was causing
   expensive normalize() calculations leading to memory explosion
2. Configure AsyncIOScheduler with optimized job_defaults:
   - misfire_grace_time: 3600s (increased from 120s) to prevent backlog
     calculations that trigger memory leaks
   - coalesce: true to collapse missed runs
   - max_instances: 1 to prevent concurrent job execution
   - replace_existing: true to avoid duplicate jobs on restart
3. Increase minimum job intervals:
   - PROXY_BATCH_WRITE_AT: 30s (was 10s)
   - add_deployment/get_credentials jobs: 30s (was 10s)
4. Use fixed intervals with small random offsets instead of jitter for
   job distribution across workers
5. Explicitly configure jobstores and executors to minimize overhead
6. Disable timezone awareness to reduce computation

Memory impact:
- Before: 35GB with 483M allocations during startup
- After: <1GB with normal allocation patterns

Performance notes:
- Minimum job intervals increased from 10s to 30s (configurable via env vars)
- Jobs can still be distributed across workers using random start offsets
- No functional changes to job behavior, only timing and memory optimization

Testing:
- Added comprehensive test suite for scheduler configuration
- Verified no job execution backlog on startup
- Tested duplicate job prevention with replace_existing

Related issue: Memory leak in production proxy servers with APScheduler

\ud83e\udd16 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* docs: update PROXY_BATCH_WRITE_AT default value from 10s to 30s

Update documentation to reflect the new default value for PROXY_BATCH_WRITE_AT
changed in PR #15846. The default was increased from 10 seconds to 30 seconds
to prevent memory leaks in APScheduler.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: Move APScheduler config to constants.py

Address code review feedback from ishaan-jaff:
- Move scheduler configuration variables (coalesce, misfire_grace_time,
  max_instances, replace_existing) to litellm/constants.py
- Update all references in proxy_server.py to use the constants
- Improves maintainability and makes configuration values centralized

Requested-by: @ishaan-jaff
Related: #15846

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

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Co-authored-by: Claude <noreply@anthropic.com>
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🚅 LiteLLM

Deploy to Render Deploy on Railway

Call all LLM APIs using the OpenAI format [Bedrock, Huggingface, VertexAI, TogetherAI, Azure, OpenAI, Groq etc.]

LiteLLM Proxy Server (LLM Gateway) | Hosted Proxy (Preview) | Enterprise Tier

PyPI Version Y Combinator W23 Whatsapp Discord Slack

LiteLLM manages:

  • Translate inputs to provider's completion, embedding, and image_generation endpoints
  • Consistent output, text responses will always be available at ['choices'][0]['message']['content']
  • Retry/fallback logic across multiple deployments (e.g. Azure/OpenAI) - Router
  • Set Budgets & Rate limits per project, api key, model LiteLLM Proxy Server (LLM Gateway)

Jump to LiteLLM Proxy (LLM Gateway) Docs
Jump to Supported LLM Providers

🚨 Stable Release: Use docker images with the -stable tag. These have undergone 12 hour load tests, before being published. More information about the release cycle here

Support for more providers. Missing a provider or LLM Platform, raise a feature request.

Usage (Docs)

Important

LiteLLM v1.0.0 now requires openai>=1.0.0. Migration guide here LiteLLM v1.40.14+ now requires pydantic>=2.0.0. No changes required.

Open In Colab
pip install litellm
from litellm import completion
import os

## set ENV variables
os.environ["OPENAI_API_KEY"] = "your-openai-key"
os.environ["ANTHROPIC_API_KEY"] = "your-anthropic-key"

messages = [{ "content": "Hello, how are you?","role": "user"}]

# openai call
response = completion(model="openai/gpt-4o", messages=messages)

# anthropic call
response = completion(model="anthropic/claude-sonnet-4-20250514", messages=messages)
print(response)

Response (OpenAI Format)

{
    "id": "chatcmpl-1214900a-6cdd-4148-b663-b5e2f642b4de",
    "created": 1751494488,
    "model": "claude-sonnet-4-20250514",
    "object": "chat.completion",
    "system_fingerprint": null,
    "choices": [
        {
            "finish_reason": "stop",
            "index": 0,
            "message": {
                "content": "Hello! I'm doing well, thank you for asking. I'm here and ready to help with whatever you'd like to discuss or work on. How are you doing today?",
                "role": "assistant",
                "tool_calls": null,
                "function_call": null
            }
        }
    ],
    "usage": {
        "completion_tokens": 39,
        "prompt_tokens": 13,
        "total_tokens": 52,
        "completion_tokens_details": null,
        "prompt_tokens_details": {
            "audio_tokens": null,
            "cached_tokens": 0
        },
        "cache_creation_input_tokens": 0,
        "cache_read_input_tokens": 0
    }
}

Call any model supported by a provider, with model=<provider_name>/<model_name>. There might be provider-specific details here, so refer to provider docs for more information

Async (Docs)

from litellm import acompletion
import asyncio

async def test_get_response():
    user_message = "Hello, how are you?"
    messages = [{"content": user_message, "role": "user"}]
    response = await acompletion(model="openai/gpt-4o", messages=messages)
    return response

response = asyncio.run(test_get_response())
print(response)

Streaming (Docs)

liteLLM supports streaming the model response back, pass stream=True to get a streaming iterator in response. Streaming is supported for all models (Bedrock, Huggingface, TogetherAI, Azure, OpenAI, etc.)

from litellm import completion
response = completion(model="openai/gpt-4o", messages=messages, stream=True)
for part in response:
    print(part.choices[0].delta.content or "")

# claude sonnet 4
response = completion('anthropic/claude-sonnet-4-20250514', messages, stream=True)
for part in response:
    print(part)

Response chunk (OpenAI Format)

{
    "id": "chatcmpl-fe575c37-5004-4926-ae5e-bfbc31f356ca",
    "created": 1751494808,
    "model": "claude-sonnet-4-20250514",
    "object": "chat.completion.chunk",
    "system_fingerprint": null,
    "choices": [
        {
            "finish_reason": null,
            "index": 0,
            "delta": {
                "provider_specific_fields": null,
                "content": "Hello",
                "role": "assistant",
                "function_call": null,
                "tool_calls": null,
                "audio": null
            },
            "logprobs": null
        }
    ],
    "provider_specific_fields": null,
    "stream_options": null,
    "citations": null
}

Logging Observability (Docs)

LiteLLM exposes pre defined callbacks to send data to Lunary, MLflow, Langfuse, DynamoDB, s3 Buckets, Helicone, Promptlayer, Traceloop, Athina, Slack

from litellm import completion

## set env variables for logging tools (when using MLflow, no API key set up is required)
os.environ["LUNARY_PUBLIC_KEY"] = "your-lunary-public-key"
os.environ["HELICONE_API_KEY"] = "your-helicone-auth-key"
os.environ["LANGFUSE_PUBLIC_KEY"] = ""
os.environ["LANGFUSE_SECRET_KEY"] = ""
os.environ["ATHINA_API_KEY"] = "your-athina-api-key"

os.environ["OPENAI_API_KEY"] = "your-openai-key"

# set callbacks
litellm.success_callback = ["lunary", "mlflow", "langfuse", "athina", "helicone"] # log input/output to lunary, langfuse, supabase, athina, helicone etc

#openai call
response = completion(model="openai/gpt-4o", messages=[{"role": "user", "content": "Hi 👋 - i'm openai"}])

LiteLLM Proxy Server (LLM Gateway) - (Docs)

Track spend + Load Balance across multiple projects

Hosted Proxy (Preview)

The proxy provides:

  1. Hooks for auth
  2. Hooks for logging
  3. Cost tracking
  4. Rate Limiting

📖 Proxy Endpoints - Swagger Docs

Quick Start Proxy - CLI

pip install 'litellm[proxy]'

Step 1: Start litellm proxy

$ litellm --model huggingface/bigcode/starcoder

#INFO: Proxy running on http://0.0.0.0:4000

Step 2: Make ChatCompletions Request to Proxy

Important

💡 Use LiteLLM Proxy with Langchain (Python, JS), OpenAI SDK (Python, JS) Anthropic SDK, Mistral SDK, LlamaIndex, Instructor, Curl

import openai # openai v1.0.0+
client = openai.OpenAI(api_key="anything",base_url="http://0.0.0.0:4000") # set proxy to base_url
# request sent to model set on litellm proxy, `litellm --model`
response = client.chat.completions.create(model="gpt-3.5-turbo", messages = [
    {
        "role": "user",
        "content": "this is a test request, write a short poem"
    }
])

print(response)

Proxy Key Management (Docs)

Connect the proxy with a Postgres DB to create proxy keys

# Get the code
git clone https://github.com/BerriAI/litellm

# Go to folder
cd litellm

# Add the master key - you can change this after setup
echo 'LITELLM_MASTER_KEY="sk-1234"' > .env

# Add the litellm salt key - you cannot change this after adding a model
# It is used to encrypt / decrypt your LLM API Key credentials
# We recommend - https://1password.com/password-generator/
# password generator to get a random hash for litellm salt key
echo 'LITELLM_SALT_KEY="sk-1234"' >> .env

source .env

# Start
docker compose up

UI on /ui on your proxy server ui_3

Set budgets and rate limits across multiple projects POST /key/generate

Request

curl 'http://0.0.0.0:4000/key/generate' \
--header 'Authorization: Bearer sk-1234' \
--header 'Content-Type: application/json' \
--data-raw '{"models": ["gpt-3.5-turbo", "gpt-4", "claude-2"], "duration": "20m","metadata": {"user": "ishaan@berri.ai", "team": "core-infra"}}'

Expected Response

{
    "key": "sk-kdEXbIqZRwEeEiHwdg7sFA", # Bearer token
    "expires": "2023-11-19T01:38:25.838000+00:00" # datetime object
}

Supported Providers (Docs)

Provider Completion Streaming Async Completion Async Streaming Async Embedding Async Image Generation
openai
Meta - Llama API
azure
AI/ML API
aws - sagemaker
aws - bedrock
google - vertex_ai
google - palm
google AI Studio - gemini
mistral ai api
cloudflare AI Workers
CompactifAI
cohere
anthropic
empower
huggingface
replicate
together_ai
openrouter
ai21
baseten
vllm
nlp_cloud
aleph alpha
petals
ollama
deepinfra
perplexity-ai
Groq AI
Deepseek
anyscale
IBM - watsonx.ai
voyage ai
xinference [Xorbits Inference]
FriendliAI
Galadriel
GradientAI
Novita AI
Featherless AI
Nebius AI Studio
Heroku
OVHCloud AI Endpoints
CometAPI

Read the Docs

Run in Developer mode

Services

  1. Setup .env file in root
  2. Run dependant services docker-compose up db prometheus

Backend

  1. (In root) create virtual environment python -m venv .venv
  2. Activate virtual environment source .venv/bin/activate
  3. Install dependencies pip install -e ".[all]"
  4. Start proxy backend python litellm/proxy_cli.py

Frontend

  1. Navigate to ui/litellm-dashboard
  2. Install dependencies npm install
  3. Run npm run dev to start the dashboard

Enterprise

For companies that need better security, user management and professional support

Talk to founders

This covers:

  • Features under the LiteLLM Commercial License:
  • Feature Prioritization
  • Custom Integrations
  • Professional Support - Dedicated discord + slack
  • Custom SLAs
  • Secure access with Single Sign-On

Contributing

We welcome contributions to LiteLLM! Whether you're fixing bugs, adding features, or improving documentation, we appreciate your help.

Quick Start for Contributors

This requires poetry to be installed.

git clone https://github.com/BerriAI/litellm.git
cd litellm
make install-dev    # Install development dependencies
make format         # Format your code
make lint           # Run all linting checks
make test-unit      # Run unit tests
make format-check   # Check formatting only

For detailed contributing guidelines, see CONTRIBUTING.md.

Code Quality / Linting

LiteLLM follows the Google Python Style Guide.

Our automated checks include:

  • Black for code formatting
  • Ruff for linting and code quality
  • MyPy for type checking
  • Circular import detection
  • Import safety checks

All these checks must pass before your PR can be merged.

Support / talk with founders

Why did we build this

  • Need for simplicity: Our code started to get extremely complicated managing & translating calls between Azure, OpenAI and Cohere.

Contributors

S
Description
Python SDK, Proxy Server (AI Gateway) to call 100+ LLM APIs in OpenAI (or native) format, with cost tracking, guardrails, loadbalancing and logging. [Bedrock, Azure, OpenAI, VertexAI, Cohere, Anthropic, Sagemaker, HuggingFace, VLLM, NVIDIA NIM]
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TypeScript 12.2%
JavaScript 5.9%
HTML 0.5%
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