# Server Utilities

Server utilities are distributed through the Tempo API library, [`tapimo`](https://npm.im/tapimo). They work with frameworks that support either:

* The [Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API) through `handler.fetch`
* The [Node.js `RequestListener` API](https://nodejs.org/api/http.html#http_class_http_serverrequestlistener) through `handler.listener`

## Connect a handler to your server

Create a handler once, then expose it through your server framework:

```ts twoslash
// @noErrors
import { createServer } from 'node:http'
import { Handler } from 'tapimo'
import { privateKeyToAccount } from 'viem/accounts'

const handler = Handler.relay({
  apiKey: process.env.TEMPO_API_KEY,
  feePayer: {
    account: privateKeyToAccount('0x...'),
  },
})

createServer(handler.listener)              // Node.js
Bun.serve({ fetch: handler.fetch })         // Bun
Deno.serve(handler.fetch)                   // Deno
app.all('*', c => handler.fetch(c.request)) // Elysia
app.use(handler.listener)                   // Express
app.use(c => handler.fetch(c.req.raw))      // Hono
export const GET = handler.fetch            // Next.js
export const POST = handler.fetch           // Next.js
```

## Handlers

* [Relay & Fee Payer Handler](/docs/server/relay-handler) — Proxy RPC requests with fee sponsorship, automatic swaps, and simulation metadata.