---
title: Files
sidebar:
  icon: file
description: Send a file up, or return one as a download - mix it with regular data.
---

`File` and `Blob` are first-class. Mix them with objects. [HTTP](/tacho/transport/http) switches to multipart when needed; JSON stays JSON. A lone returned `File` is a download (`Content-Disposition`).

```ts twoslash server.ts
import { tacho } from "tacho";
import { z } from "zod";

const rpc = tacho();

export const router = rpc({
  upload: rpc
    .input(z.object({ file: z.instanceof(File), note: z.string() }))
    .run(({ input }) => input.file.name),
  download: rpc.run(
    () => new File(["hello"], "hello.txt", { type: "text/plain" }),
  ),
});

export type Router = typeof router;
```

```ts twoslash client.ts
// @filename: server.ts
import { tacho } from "tacho";
import { z } from "zod";

const rpc = tacho();
export const router = rpc({
  upload: rpc
    .input(z.object({ file: z.instanceof(File), note: z.string() }))
    .run(({ input }) => input.file.name),
  download: rpc.run(
    () => new File(["hello"], "hello.txt", { type: "text/plain" }),
  ),
});
export type Router = typeof router;
// ---cut---
// @filename: client.ts
import { createClient } from "tacho/client/http";
import type { Router } from "./server";

const client = createClient<Router>({
  url: "http://localhost:3000",
});

await client.upload({
  file: new File(["hi"], "hi.txt"),
  note: "ok",
});
const file = await client.download();
await file.text();
```