FAQ

The questions we get most often, in one place. https://useupup.com/faq and faq.useupup.com both land here.

Which frameworks does upup support?

upup ships one uploader with native UI packages for React, Vue, Svelte, Angular, Vanilla JS, and Preact. Every framework renders the same DOM structure, classes, and accessibility tree, verified by a cross-framework parity test suite, so the uploader looks and behaves the same everywhere. Next.js gets its own package, @useupup/next, which bundles the React UI with server route handlers.

Is upup free and open source?

Yes. upup is MIT-licensed and free to use in commercial and personal projects. The source lives on GitHub at github.com/DevinoSolutions/upup. There is no hosted service, no account, and no paid tier — uploads go to storage you own.

Does upup work with S3-compatible storage like MinIO or Cloudflare R2?

Yes. upup uploads to any S3-compatible storage, including AWS S3, Cloudflare R2, MinIO, DigitalOcean Spaces, Backblaze B2, Wasabi, and more, as well as Azure Blob Storage. Provider-specific setup, including the CORS rules each bucket needs, is under Guides → Storage.

Which cloud drives can users upload from?

Users can import files directly from Google Drive, OneDrive, Dropbox, and Box. upup also supports uploads from the device camera, screen capture, and link (URL) imports. Each drive needs an OAuth client from that provider's developer console; see Credentials configuration.

What is the difference between client mode and server mode?

In client mode the browser uploads directly to your storage using short-lived credentials issued by your server. In server mode uploads are proxied through your own server using the @useupup/server package, which isolates storage credentials behind an HMAC-signed trust model. Start with Server Mode — Setup when you need server mode.

Can I use my own UI with upup?

Yes. The engine lives in @useupup/core, a framework-agnostic headless package. You can use the built-in native UI for your framework or build a fully custom interface on the same core using the exported hooks and controllers. See Headless core.

Why does createUpupHandler throw at startup?

The server handler requires an uploadTokenSecret of at least 16 characters and throws at construction time if it is missing or too short — it is the key that HMAC-signs every upload token, so the handler refuses to start without one. Set it from an environment variable and keep it identical on every server instance. Details in Server Mode — Setup.

Why do uploads fail with a CORS error?

In client mode the browser PUTs bytes straight to your bucket, so the bucket itself must allow your origin, the PUT method, and the headers the presigned URL carries. The per-provider pages under Guides → Storage include the exact CORS rule to apply. The presign endpoint returning a URL but the upload failing afterwards is almost always this.

Which React and Next.js versions are required?

@useupup/react and @useupup/preact require React 19. @useupup/next requires Next.js 15 or newer. If you are on Next.js, add serverExternalPackages: ['@aws-sdk/client-s3', '@aws-sdk/s3-request-presigner'] to next.config so the AWS SDK stays out of your client bundle — see the Next.js quickstart.

Why is the image editor missing in Vue, Svelte, Angular, or Vanilla JS?

The image editor (crop, rotate, annotate) ships for React and Preact only; the other frameworks intentionally stub it. Every other feature — cloud drives, camera, screen capture, link import, compression, HEIC conversion, resumable uploads, i18n, and theming — is identical across all six frameworks.

How do I set up an AI coding agent to use upup?

Copy the "Onboard your agent to upup" prompt from /agent-setup/ and paste it into Claude Code, Codex, Cursor, or OpenCode. The agent fetches /agent-setup/prompt.md, installs the right @useupup/* package, mounts the uploader, and saves a verified context block into its instructions file. The context block on its own is on Use upup with AI assistants.

Where do I ask something that is not answered here?

Open a GitHub issue for bugs and feature requests, or use the support form to reach the team directly.