Examples

Cloudflare Worker + R2

import { signRequest, presignUrl } from "sigv4-lite";

function r2Config(env) {
  return {
    accessKeyId: env.R2_ACCESS_KEY_ID,
    secretAccessKey: env.R2_SECRET_ACCESS_KEY,
    region: "auto",
    endpoint: `https://${env.R2_ACCOUNT_ID}.r2.cloudflarestorage.com`,
    bucket: env.R2_BUCKET,
  };
}

async function putObject(env, key, body, contentType) {
  const { accessKeyId, secretAccessKey, region, endpoint, bucket } = r2Config(env);
  const url = `${endpoint}/${bucket}/${key}`;

  const headers = await signRequest({
    method: "PUT",
    url,
    body,
    accessKeyId,
    secretAccessKey,
    region,
    headers: { "content-type": contentType },
  });

  return fetch(url, { method: "PUT", headers, body });
}

Presigned download link

const link = await presignUrl({
  url: `${endpoint}/${bucket}/${key}`,
  accessKeyId,
  secretAccessKey,
  region: "auto",
  expiresIn: 3600,
});

Testing against a public S3-compatible playground

play.min.io runs a public MinIO demo server with openly published test credentials, useful for a quick sanity check without setting up a real bucket.

import { signRequest } from "sigv4-lite";

const base = {
  accessKeyId: "Q3AM3UQ867SPQQA43P2F",
  secretAccessKey: "zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG",
  region: "us-east-1",
};

const url = "https://play.min.io/my-bucket/hello.txt";

const headers = await signRequest({ method: "PUT", url, body: "hi", ...base });
await fetch(url, { method: "PUT", headers, body: "hi" });

This is a shared public server — don’t store anything sensitive there.