Delivery

The delivery endpoint is the single URL you put in <img>, <audio>, or <video> tags. It detects the file type and routes to the right transformer automatically.

URL format

GET /f/:projectSlug/:path?<transform-params>

Segment	Description
`:projectSlug`	The project's URL-safe slug (e.g. `my-app`)
`:path`	The object key inside the bucket (e.g. `images/photo.jpg`)

Authentication

Project visibility	Auth required
`public`	None
`private`	`Authorization: Bearer <read-key>` header, or `?token=<signed-token>` in the URL

Image transforms (via imgproxy)

Triggered when the source file is an image (jpg, jpeg, png, gif, webp, avif, tiff, bmp, svg, ico).

Also triggered for video thumbnail extraction when ?format=<image-format> is used on a video.

Param	Type	Description
`format`	string	Output format: `webp`, `avif`, `jpg`, `png`, `gif`
`w`	number	Width in pixels (`0` = auto)
`h`	number	Height in pixels (`0` = auto)
`q`	number	Quality 1–100
`fit`	`fit` \| `fill` \| `auto`	Resize mode
`blur`	number	Blur sigma

Examples:

# Convert to WebP at 800px wide
/f/my-app/images/photo.jpg?format=webp&w=800

# Thumbnail with quality and crop
/f/my-app/images/photo.jpg?format=avif&w=400&h=400&fit=fill&q=80

# Video thumbnail (first frame as JPEG)
/f/my-app/videos/promo.mp4?format=jpg&w=1280

The response is a 302 redirect to the signed imgproxy URL. imgproxy fetches the source directly from MinIO via the S3 protocol.

Video & Audio transforms (via FFmpeg)

Triggered when the source is a video or audio file and ?format= is an audio/video format that differs from the source.

Source	Valid `?format=` values
Video (`mp4`, `mov`, `webm`, `mkv`, `avi`)	`mp4`, `mov`, `webm`, `mkv`, `avi`, `mp3`, `aac`, `ogg`, `flac`, `m4a`, `wav`
Audio (`mp3`, `wav`, `aac`, `ogg`, `flac`, `m4a`)	`mp3`, `wav`, `aac`, `ogg`, `flac`, `m4a`

Examples:

# Convert MP4 to WebM
/f/my-app/videos/promo.mp4?format=webm

# Extract audio track as MP3
/f/my-app/videos/promo.mp4?format=mp3

# Convert WAV to AAC
/f/my-app/audio/track.wav?format=aac

Caching behaviour

First request — FFmpeg transcodes and streams output to the browser progressively. Simultaneously, the result is saved to MinIO at _cache/<projectId>/<path>__<format>.
Subsequent requests — Contento finds the cached entry in transform_jobs and returns a 302 redirect to the cached MinIO object. No re-transcoding.

No-op guard

If ?format= matches the source extension (e.g. video.mp4?format=mp4), Contento skips FFmpeg and serves the raw file directly.

Raw delivery (no transform)

When no transform params are provided:

Public project → 302 to the MinIO public URL
Private project → 302 to a MinIO presigned GET URL (1 hour expiry)