# Command line

**You will:** Check that a data connector follows the lelemon-connector/v1 format, and serve a fixture while you build the real one.

**You need:**
- Node.js 20 or later
- No API key: the command never calls Lelemon

The package `@lelemon-ai/sdk` installs a `lelemon` command. It has one group, `connector`, with two commands: `validate` checks documents against the format and `serve` answers the four requests of a connector from a file. Both run on your machine. Nothing is sent to Lelemon.

## Works in two minutes

Save this fixture as `fixture.json`. It is a connector with one account.

```json title="fixture.json"
{
  "manifest": {
    "format": "lelemon-connector/v1",
    "name": "Acme back office",
    "lookup": { "byId": true, "byEmail": true },
    "views": []
  },
  "accounts": [
    {
      "email": "ana@acme.example",
      "object": "account",
      "id": "acc_1",
      "title": "Acme SpA",
      "sections": [
        {
          "title": "Plan",
          "components": [
            { "type": "field", "key": "plan", "label": "Plan", "valueType": "text", "value": "Pro" }
          ]
        }
      ]
    }
  ]
}
```

In one terminal, serve it. In another, validate what it serves:

```bash
npx -y -p @lelemon-ai/sdk lelemon connector serve --fixture fixture.json

npx -y -p @lelemon-ai/sdk lelemon connector validate http://127.0.0.1:4300 --account acc_1
```

Expected:

```text
Serving fixture.json at http://127.0.0.1:4300 (signatures are not checked)
```

```text
ok    manifest  http://127.0.0.1:4300/manifest
ok    account  http://127.0.0.1:4300/accounts/acc_1
```

If you installed the SDK in a project (`npm install @lelemon-ai/sdk`), run `npx lelemon connector ...` instead. The format is explained in [Connect your back office](/guides/data-connectors).

## `lelemon connector validate`

```text
lelemon connector validate <url|file> [--type manifest|account|accountSearch|view]
                                      [--account <id>] [--header "Name: value"]
```

`validate` reads a target and checks it with the same validator Lelemon uses on the real answers of your system.

- **A URL** is a base URL of a connector. The command reads `GET {base}/manifest`, then `GET {base}/views/{id}` for each view the manifest declares, and `GET {base}/accounts/{id}` when you pass `--account`. Each document gets its own line.
- **A file** is one JSON document. The command detects its type, or you force it with `--type`.

| Option | Use |
| --- | --- |
| `<url\|file>` | Required. A base URL that starts with `http://` or `https://`, or the path of a JSON file |
| `--type` | The type of the document: `manifest`, `account`, `accountSearch` or `view`. Needed for a file the command cannot detect, and it overrides detection. Ignored for a URL, where each type is known |
| `--account` | An account id to read and validate, for a URL target |
| `--header` | `"Name: value"` sent with every request to a URL. Repeat it for several headers, such as a bearer token of your system |

Each line starts with `ok` or `fail`, then the document type and its source. A `fail` is followed by one line per problem with its path and the rule it breaks:

```text
fail  account  bad.json
        $.title  is required
        $.sections  is required
```

| Exit code | Meaning |
| --- | --- |
| `0` | Every document follows the format |
| `1` | At least one document does not |
| `2` | The command was used wrong: a missing argument, an unknown option or type, or a fixture that does not load |

A document that cannot be read (a connection error, a status other than `2xx`, or an answer that is not JSON) counts as a `fail` with the reason in the problem. Use the exit code in CI to stop a deploy that breaks the format. When the connector is registered, `POST /v2/data-connectors/{id}/check` validates the manifest your system really serves, and `POST /v2/data-connectors/format/validate` validates a document through the API.

## `lelemon connector serve`

```text
lelemon connector serve --fixture <file> [--port 4300] [--secret <signing secret>]
```

`serve` starts a local HTTP server on `127.0.0.1` that answers the four requests of a connector from a fixture, so you can build the UI that reads it or point a registered connector at a tunnel before your own system exists.

| Option | Default | Use |
| --- | --- | --- |
| `--fixture` | none | Required. A JSON file with `manifest`, `accounts` and `views` |
| `--port` | `4300` | The port to listen on |
| `--secret` | none | A signing secret. With it, every request must carry a valid Lelemon signature and the server answers `401 invalid_signature` otherwise. Without it, signatures are not checked |

The fixture has three keys:

- `manifest`: the manifest document.
- `accounts`: a list of account cards. Each may carry an extra `email`, used only to answer `GET /accounts?email=` and never returned.
- `views`: an object that maps a view id to the page it returns.

The fixture is validated when it loads. A document that does not follow the format stops the command with exit code `2` and the failing paths, so you never serve something invalid by mistake.

The server answers `GET` only (`405` otherwise) and these routes:

| Route | Answers |
| --- | --- |
| `/manifest` | The manifest |
| `/accounts?email=` | The accounts whose `email` matches, as a list of `{ id, title, subtitle }` |
| `/accounts/{id}` | The card, or `404 account_not_found` |
| `/views/{id}` | The page, or `404 view_not_found` |

The command runs until you stop it with Ctrl+C. To test the signature check, pass the signing secret of the connector with `--secret`; see [Verify that a call is from Lelemon](/guides/data-connectors#verify-that-a-call-is-from-lelemon).

## What's next

- [Connect your back office](/guides/data-connectors) for the format, the registration and the copilot.
- [TypeScript SDK](/tools/sdk) for the `connector` helpers that build the documents in code.