SDK 2.0: Zero Dependencies, Native Fetch, and Smarter Media Uploads

The @cosmicjs/sdk has been rebuilt from the inside out. Version 2.0 removes all runtime dependencies, replaces axios with the native fetch API, and adds automatic MIME type detection for media uploads. The public API is unchanged — upgrade with confidence.

Zero Runtime Dependencies

The SDK no longer ships with axios or form-data. Every HTTP request now goes through the native fetch, FormData, and Blob APIs built into Node.js 18+ and all modern browsers.

• Before: 2 runtime dependencies (axios, form-data) plus 7 transitive packages
• After: 0 runtime dependencies
• Result: Smaller node_modules, faster installs, reduced supply chain surface area

Native Fetch

All request handling has been rewritten to use the Fetch API. This means the SDK works identically in Node.js, Bun, Deno, Cloudflare Workers, and the browser without polyfills or adapters.

// Nothing changes in your application code
import { createBucketClient } from '@cosmicjs/sdk'

const cosmic = createBucketClient({
  bucketSlug: 'YOUR_BUCKET_SLUG',
  readKey: 'YOUR_READ_KEY',
  writeKey: 'YOUR_WRITE_KEY',
})

const { objects } = await cosmic.objects
  .find({ type: 'posts' })
  .props(['title', 'slug', 'metadata'])
  .limit(10)

Automatic MIME Type Detection for Media Uploads

Media uploads now automatically detect the correct MIME type from the filename. Previously, uploads without an explicit contentType were sent as application/octet-stream, which could cause issues with image processing and CDN optimization.

The SDK recognizes 25+ file types out of the box — images, video, audio, documents, fonts, and more.

// MIME type is inferred from the filename
const buffer = fs.readFileSync('photo.jpg')
await cosmic.media.insertOne({
  media: buffer,
  filename: 'photo.jpg', // → image/jpeg detected automatically
})

// Or with the object format
await cosmic.media.insertOne({
  media: { buffer, originalname: 'hero.webp' }, // → image/webp
})

// You can still set it explicitly
await cosmic.media.insertOne({
  media: buffer,
  filename: 'data.bin',
  contentType: 'application/custom-type',
})

Batch Operations

Also new since 1.8: the objects.batch() method lets you create, update, and delete multiple objects in a single API call. Each operation succeeds or fails independently.

await cosmic.objects.batch([
  { method: 'add', object: { title: 'Post 1', type: 'posts' } },
  { method: 'add', object: { title: 'Post 2', type: 'posts' } },
  { method: 'edit', object_id: 'existing-id', object: { title: 'Updated' } },
  { method: 'delete', object_id: 'old-id' },
])

Breaking Changes

Node.js 18+ is required. The native fetch API was added in Node.js 18.0. If you're on an older version, stay on @cosmicjs/sdk@1.x.

That's the only breaking change. The entire public API — objects, media, object types, object revisions, and AI — is fully backward compatible.

Upgrade

npm install @cosmicjs/sdk@latest
# or
bun add @cosmicjs/sdk@latest

Full Changelog

Read the docs: API Reference, SDK on npm