Convert API

Server-side image conversion. POST an image, get AVIF/WebP/PNG/JPEG back.

What is it?

POST /api/convert accepts a multipart form with an image file and optional format/quality. The response is the converted image binary. You must send a valid API key in the request (create one after signing in with GitHub).

Authentication

Every request must include your API key in the header:

Authorization: Bearer YOUR_API_KEY

Create and manage keys (after signing in):

API Keys →

Endpoint

POST /api/convert

Request (multipart/form-data)

Field	Required	Description
file	✅	Image file (AVIF, WebP, PNG, JPEG, GIF). Max 20MB.
format	-	Output format: avif, webp, png, jpeg. Default: avif.
quality	-	Quality 1–100. Default: 75. Ignored for png.
speed	-	AVIF encode speed 0–10 (higher = faster, lower compression). Default: 5.

Examples

cURL

curl -X POST \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F file=@image.png \
  -F format=avif \
  -F quality=80 \
  https://getavif.com/api/convert \
  -o out.avif

Fetch (JavaScript)

const formData = new FormData();
formData.append("file", imageFile);
formData.append("format", "avif");
formData.append("quality", "80");

const res = await fetch("https://getavif.com/api/convert", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${YOUR_API_KEY}`,
  },
  body: formData,
});

if (!res.ok) throw new Error(await res.text());
const blob = await res.blob();
// e.g. save or use blob

Replace YOUR_API_KEY with your API key.

Response

200: binary image with Content-Type (e.g. image/avif) and Content-Disposition attachment. 400: invalid request. 401: missing or invalid API key. 503: conversion or key validation unavailable.

Errors

All errors return JSON with an "error" field. Use GET /api/convert for a short usage summary.