Quickstart & reference

Three steps to your first transform.

Point Refract at an existing image origin and drive every transform from the URL. Originals are fetched on demand and edge-cached — never stored permanently.

Quickstart

Run log.

Create a key, connect your origin.

Create an API key and point Refract at your existing image origin. No re-upload — originals are fetched on demand.

Request your first transform.

Append parameters to any image path and request it straight from the edge.

https://demo.refract.dev/hero.jpg?w=1200&fm=auto&q=80

Automate with the SDK.

Build request URLs in code with the JavaScript client.

import { refract } from "@refract/js";

const url = refract("hero.jpg", { width: 1200, format: "auto", quality: 80 });
// → https://demo.refract.dev/hero.jpg?w=1200&fm=auto&q=80

Parameter reference

Ten chainable parameters.

Parameter Accepts Description Value

integer, px

Width in pixels.

1200

integer, px

Height in pixels.

—

fit

cover · contain · fill · crop

Resize mode.

—

fmNegotiated

jpeg · png · webp · avif · auto

Output format. auto negotiates AVIF → WebP → JPEG.

auto

qNegotiated

1–100

Quality. Default 75.

dprNegotiated

1–3

Device pixel ratio.

—

crop

smart · center · edges

Crop strategy. Smart keeps subjects in frame.

—

rot

90 · 180 · 270

Rotation, degrees.

—

blur

0–100

Gaussian blur.

—

hex color

Background fill for contain.

—

A dash marks an unset channel. fm, q, and dpr are negotiated from the request's Accept and client headers.

Caching & limits

What the edge holds.

0req/s

Rate limit · per key, all tiers

0days

Transformed variants cached at the edge

Instant

Purge by URL or tag

Point Refract at your origin; originals are fetched on demand and edge-cached up to 30 days, never stored permanently.