# Upstash QStash SDK
> [!NOTE]
> **This project is in GA Stage.**
> The Upstash Professional Support fully covers this project. It receives regular updates, and bug fixes.
> The Upstash team is committed to maintaining and improving its functionality.
**QStash** is an HTTP based messaging and scheduling solution for serverless and
edge runtimes.
It is 100% built on stateless HTTP requests and designed for:
- Serverless functions (AWS Lambda ...)
- Cloudflare Workers (see
[the example](https://github.com/upstash/sdk-qstash-ts/tree/main/examples/cloudflare-workers))
- Fastly Compute@Edge
- Next.js, including [edge](https://nextjs.org/docs/api-reference/edge-runtime)
- Deno
- Client side web/mobile applications
- WebAssembly
- and other environments where HTTP is preferred over TCP.
## How does QStash work?
QStash is the message broker between your serverless apps. You send an HTTP
request to QStash, that includes a destination, a payload and optional settings.
We durably store your message and will deliver it to the destination API via
HTTP. In case the destination is not ready to receive the message, we will retry
the message later, to guarentee at-least-once delivery.
## Quick Start
### Install
#### npm
```bash
npm install @upstash/qstash
```
### Get your authorization token
Go to [Upstash Console](https://console.upstash.com/qstash) and copy the QSTASH_TOKEN.
## Basic Usage:
### Publishing a message
```ts
import { Client } from "@upstash/qstash";
/**
* Import a fetch polyfill only if you are using node prior to v18.
* This is not necessary for nextjs, deno or cloudflare workers.
*/
import "isomorphic-fetch";
const client = new Client({
token: "<QSTASH_TOKEN>",
});
const res = await client.publishJSON({
url: "https://my-api...",
// or urlGroup: "the name or id of a url group"
body: {
hello: "world",
},
});
console.log(res);
// { messageId: "msg_xxxxxxxxxxxxxxxx" }
```
The token is optional: without it, the client reads `QSTASH_TOKEN` and
`QSTASH_URL` from the environment. You can also create the client from the
environment explicitly:
```ts
const client = Client.fromEnv();
```
### Receiving a message
How to receive a message depends on your http server. The `Receiver.verify`
method should be called by you as the first step in your handler function.
```ts
import { Receiver } from "@upstash/qstash";
const r = new Receiver({
currentSigningKey: "..",
nextSigningKey: "..",
});
const isValid = await r.verify({
/**
* The signature from the `Upstash-Signature` header.
*
* Please note that on some platforms (e.g. Vercel or Netlify) you might
* receive the header in lower case: `upstash-signature`
*
*/
signature: "string";
/**
* The raw request body.
*/
body: "string";
})
```
### Publishing a message to an LLM provider
No need for complicated setup your LLM request. We'll call LLM and schedule it for your serverless needs.
```ts
import { Client, openai } from "@upstash/qstash";
const client = new Client({
token: "<QSTASH_TOKEN>",
});
const result = await client.publishJSON({
api: { name: "llm", provider: openai({ token: process.env.OPENAI_API_KEY! }) },
body: {
model: "gpt-3.5-turbo",
messages: [
{
role: "user",
content: "Where is the capital of Turkey?",
},
],
},
callback: "https://oz.requestcatcher.com/",
});
```
## Local Development
Set `QSTASH_DEV=true` in your environment variables, and the SDK will download and connect to a local QStash dev server automatically. No tokens or signing keys required: the SDK injects deterministic dev credentials.
```bash .env
QSTASH_DEV=true
```
Alternatively, pass `devMode: true` to explicitly enable dev mode:
```ts
import { Client } from "@upstash/qstash";
const client = new Client({ devMode: true });
```
The same flag works on the receiving side: pass `devMode: true` to `Receiver` or `verifySignature*` to verify signatures with the dev server's keys. Dev mode is automatically a no-op when `NODE_ENV=production` and in browser/edge runtimes.
See [Local Development](https://docs.upstash.com/qstash/howto/local-development) for the full walkthrough, including the `registerQStashDev()` helper for Next.js edge routes.
## Docs
See [the documentation](https://docs.upstash.com/qstash) for details.
The npm package includes documentation in `node_modules/@upstash/qstash/docs/`
and TypeScript source in `node_modules/@upstash/qstash/src/` for offline reference
and coding agents. Start with `docs/overview.mdx`; the SDK entrypoint is
in `src/src/index.ts` and platform adapters are in `src/platforms/`.
## Telemetry
This sdk sends anonymous telemetry headers to help us improve your experience.
We collect the following:
- SDK version
- Platform (Cloudflare, AWS or Vercel)
- Runtime version (node@18.x)
You can opt out by setting the `UPSTASH_DISABLE_TELEMETRY` environment variable
to any truthy value. Or setting `enableTelemetry: false` in the client options.
```ts
const client = new Client({
token: "<QSTASH_TOKEN>",
enableTelemetry: false,
});
```
## Contributing
### Setup
This project requires [Bun](https://bun.sh/) to be installed. Please see the [Bun installation documentation](https://bun.sh/docs/installation) for further instructions.
Once you have cloned the project, you will need to install the dependencies and then you can run the project.
```sh
bun install
bun run build
```
### Testing
To begin testing, environment variables will need to be setup. First, create a `.env` file in the root of the project. [`.env.template`](/.env.template) can be used as a template. Your values can be found in the [Qstash Console](https://console.upstash.com/qstash).
```sh
bun run test
```
### Committing
This project uses [commitlint](https://commitlint.js.org/). When committing, please ensure your commit message is formatted to include an appropriate prefix with the message.
#### Examples
```
fix: typescript bug
feat: use new logger
perf: refactor cache
```
For a full list of options, please see the [`commitlint.config.js`](/commitlint.config.js) file.