## Prerequisites

Before using the API, you need:

* [Install and start Langflow](/get-started-installation) with the developer API enabled

    The Workflows API endpoints require the `developer_api_enabled` setting to be enabled. If this setting is disabled, these endpoints will return a 404 Not Found error.

    To enable the developer API endpoint, do the following:
    1. In the Langflow `.env` file, set the environment variable to `true`:
       ```
       LANGFLOW_DEVELOPER_API_ENABLED=true
       ```
    2. Start your Langflow server with the `.env` file enabled:
       ```
       uv run langflow run --env-file .env
       ```

    For more information about configuring environment variables, see [Environment variables](/environment-variables).
* [Create a Langflow API key](/api-keys-and-authentication)
* [Create a flow](/concepts-flows) that you want to execute
* [Get the flow ID](/concepts-publish#api-access) or endpoint name of the flow you want to execute

### Set environment variables

All code examples in this documentation assume you have set the following environment variables:

**Python:**
```python
import os

LANGFLOW_SERVER_URL = os.getenv("LANGFLOW_SERVER_URL")
LANGFLOW_API_KEY = os.getenv("LANGFLOW_API_KEY")
```

**TypeScript/JavaScript:**
```typescript
const LANGFLOW_SERVER_URL = process.env.LANGFLOW_SERVER_URL;
const LANGFLOW_API_KEY = process.env.LANGFLOW_API_KEY;
```

Set these environment variables before running the examples, or replace the variable references in the code examples with your actual Langflow server URL and API key.

The default `LANGFLOW_SERVER_URL` for a local Langflow deployment is `http://localhost:7860`.
For remote deployments, the domain is set by your hosting service, such as `https://UUID.ngrok.app`.

### Authentication and headers

All Workflows API requests require authentication using a Langflow API key. The API key is passed in the `x-api-key` header.

For more information, see [Create a Langflow API key](/api-keys-and-authentication).

| Header | Description | Example |
|--------|-------------|---------|
| `Content-Type` | Specifies the JSON format. | `application/json` |
| `x-api-key` | Your Langflow API key. | `sk-...` |
| `accept` | Optional. Specifies the response format. | `application/json` |