@workos/alto

@workos/alto

Identity and platform access for applications running on Alto. See the application authoring guide for setup and runtime contracts.

Images

Declare resources.images: [{ binding: "IMAGES" }] in alto.json and use transformImage from version 0.12.0 or later:

import { transformImage } from "@workos/alto";

const image = await transformImage(env.IMAGES, sourceStream, {
  format: "image/webp",
  width: 128,
  height: 128,
  fit: "cover",
  quality: 80,
});

The input is a ReadableStream<Uint8Array> and the output is a Response. format is required and accepts image/webp or image/png. Width and height are optional positive integers, fit accepts cover, and optional quality is 1–100. Fetch or read source bytes in the app and provide a fresh stream for each output. Return the response to a browser or consume its bytes for storage.

The same helper uses Alto's transformation service in production and an offline native Images binding in local development. See the Images contract for declarations, migration examples, local setup and shared provider limits.