# Functions quickstart (/using/functions/quickstart)



<AlphaNotice />

This takes a running self-hosted stack to a function you can call. It needs a [database](/using/projects-and-databases) that is ready, Node.js (for esbuild) and the `chelabase` CLI. From a checkout of the repository, `cargo run -p chelabase --` stands in for `chelabase` in every command below.

## 1. Sign in [#1-sign-in]

```bash
chelabase login --url http://api.chelabase.localhost:8000 --email you@example.com
```

The password is prompted for (or read from stdin). The session is kept per instance URL in `~/.config/chelabase/credentials.json`, mode 0600, and the CLI never prints the token. An account that has a second sign-in step gets a clear error: only password sign-in is supported.

## 2. Make a project [#2-make-a-project]

Choose a folder, install esbuild, and write `chelabase.toml`. The database id is on the database's page in Studio, and in `GET /v1/databases`.

```bash
mkdir hello-functions && cd hello-functions
npm init -y
npm install --save-dev esbuild
mkdir -p functions/hello
```

**`chelabase.toml`**

```toml
[project]
url = "http://api.chelabase.localhost:8000"
database = "<your database id>"

[functions.hello]
entry = "functions/hello/index.ts"
```

**`functions/hello/index.ts`**

```ts
export default {
  async fetch(request: Request): Promise<Response> {
    const name = new URL(request.url).searchParams.get("name") ?? "world";
    return Response.json({ hello: name });
  },
};
```

With no `branch`, the CLI uses the database's main branch. The full format is in [the project file](/using/functions/project-file).

## 3. Deploy, and keep deploying on save [#3-deploy-and-keep-deploying-on-save]

```bash
chelabase functions dev --watch
```

`dev` deploys every function in `chelabase.toml`, then redeploys each one whose files change. For each deploy it prints the deployment id and, on a change, how long the change took to go live:

```text
hello: deployed 6f1c…
hello: deployed 0b8e… (412 ms after the change)
```

The first deploy creates the function and turns it on. A syntax error prints esbuild's message and leaves the previous deployment live. (`chelabase functions deploy` does one deploy and exits.)

## 4. Call it [#4-call-it]

Take the branch's **public key** (`chk_pub_…`) from the database's **Data API** view in Studio, and call the function:

```bash
export CHELABASE_PUBLIC_KEY=chk_pub_…
curl -H "Authorization: Bearer $CHELABASE_PUBLIC_KEY" \
  "http://api.chelabase.localhost:8000/functions/v1/hello?name=Ada"
```

```json
{"hello":"Ada"}
```

Edit the file while `dev --watch` runs, save, and call again: the new code answers within a couple of seconds.

## Where next [#where-next]

* [Handlers](/using/functions/handlers): `fetch`, `scheduled` and event payloads.
* [Secrets, env and the data API](/using/functions/environment): read and write your database from a function.
* [Auth modes and limits](/using/functions/auth-and-limits).
* [Schedules](/using/functions/schedules) and [Triggers](/using/functions/triggers).