docs(readme): correct to HTTP microservice, add usage, output formats, related link

webp-converter/README.md

@@ -1,28 +1,47 @@
 # webp-converter
 
-CLI tool written in Go to convert WebP images to other formats (PNG, JPG, etc.).
+Lightweight HTTP microservice written in Go that converts WebP images to PNG on-the-fly — accepts an image URL, returns the converted PNG bytes.
 
 ## Quick start
 
-```bash
-go install github.com/tiennm99/webp-converter@latest
-webp-converter -input image.webp -output image.png
-```
-
-Or build from source:
-
 ```bash
 go build -o webp-converter .
-./webp-converter -input image.webp -output image.png
+./webp-converter
+# Server listens on :8080
 ```
 
 Docker:
 
 ```bash
 docker build -t webp-converter .
-docker run --rm -v $(pwd):/data webp-converter -input /data/image.webp -output /data/image.png
+docker run --rm -p 8080:8080 webp-converter
 ```
 
+## Usage
+
+POST a JSON body with the source image URL to `/process`:
+
+```bash
+curl -X POST http://localhost:8080/process \
+  -H "Content-Type: application/json" \
+  -d '{"img": "https://example.com/image.webp"}' \
+  --output image.png
+```
+
+- If the URL points to a **WebP** image, the response is the converted **PNG**.
+- If the URL points to any other format, the original image bytes are returned unchanged (pass-through).
+
+## Output formats
+
+| Input | Output |
+|-------|--------|
+| WebP | PNG |
+| Any other format | Original (pass-through) |
+
+## Related
+
+- [image-resizer](https://github.com/tiennm99/image-resizer) — batch-resize images by percentage (same domain, different operation).
+
 ## License
 
 Apache-2.0 — see [LICENSE](LICENSE).