Use case

A drop box for your team

One route on your own domain, a token per person, and a code instead of a chat upload.

Setting up a server, in full s3nd @s3nd/cli

app/api/transfers/[[...route]]/route.ts

import { createBucket, createTransferHandler } from 's3nd'

const tokens = new Set(process.env.DROP_TOKENS!.split(','))

export const { GET, POST, DELETE } = createTransferHandler({
  bucket: createBucket({ bucket: 'drop' }),
  expiresIn: 24 * 3600,
  raw: 'redirect', // downloads go straight from the bucket, presigned
  authorize: (request) => tokens.has(request.headers.get('authorization')?.replace('Bearer ', '') ?? ''),
})

// $ s3nd --remote https://drop.example.com/api/transfers --token $TOKEN put ./deck.pdf

The situation

What is actually going on.

The problem

Files move around a team as chat uploads and email attachments, each one a copy on somebody else’s servers. Handing everyone the bucket keys is not an option, and a shared drive is a different kind of mess.

What s3nd does about it

Mount the transfer handler on a domain you own and pass an authorize function that checks a bearer token. Each person has a token, not a key. The CLI points at it with --remote, a browser uses the same four routes through the React hooks, and curl works too. Files land in your bucket under a code and expire on their own.

Worth watching

The things that are easy to get wrong.

Rate-limit the lookup

A code is a bearer token and forty bits is the whole secret. A rate limit on GET /:code is what makes guessing pointless.

raw: redirect for big files

With it, a download answers 302 with a presigned URL, so the bytes never transit your server twice. Without it they stream through, which is fine for small files and expensive for large ones.

doctor --remote as the smoke test

It round-trips a real transfer against the deployment and exits non-zero on failure. Put it in the deploy pipeline.

Packagess3nd@s3nd/cli

Other shapes of the same primitive.

A file between two machines

A laptop, a desktop, a code. No server, no account, through the bucket you already have.

Backups from CI

A nightly archive to your bucket from a workflow, with secrets from the runner and no file to check in.

Move an app to a new device

A local-first app with no accounts. A code on the old phone, typed into the new one, and the whole database follows.

Put a file. Hand over the code.

Point it at the bucket you already pay for. Nothing to deploy, nothing to sign up for, nothing in the middle.

Install the CLI Put it in your app GitHub

$npm install -g @s3nd/cli$s3nd init --provider r2 --bucket drop$s3nd put ./anything.zip