chore: update README

README.md

@@ -14,4 +14,34 @@ Simple, bullshit-free QR code generator with straightforward API.
 
 ## Stack
 
-- [Nuxt 4](https://nuxt.com) + [Nuxt UI](https://ui.nuxt.com)a
+- [Nuxt 4](https://nuxt.com) + [Nuxt UI](https://ui.nuxt.com)
+
+## API
+
+### `GET /api` - Generate a QR code
+
+Returns the QR code as an image file.
+
+| Parameter | Type                      | Required | Description                                         |
+|-----------|---------------------------|----------|-----------------------------------------------------|
+| `content` | string                    | yes      | Data to encode                                      |
+| `format`  | `png` \| `jpeg` \| `webp` | no       | Output format (default: `png`)                      |
+| `logo`    | string                    | no       | Logo name to embed in the center (case-insensitive) |
+
+**Example:**
+```
+GET https://simple-qr.com/api?content=https://git.pihkaal.me&format=webp&logo=gitea
+```
+
+### `GET /api/logos` - List available logos
+
+Returns a JSON array of available logo names.
+
+**Example:**
+```
+GET https://simple-qr.com/logos
+```
+
+```json
+["signal", "monero", "session", ...]
+```