> ## Documentation Index
> Fetch the complete documentation index at: https://arnaud.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> Authenticate requests using an API key.

All requests to the Current Weather Data API require an API key.

## Get an API key

If you don’t have an API key yet:

1. [Sign in to your account](https://openweathermap.org/home/sign_in).
2. In the top menu, click your name > **My API keys**.

Make sure your API key is **Active**.

## Use your API key

Include your API key in every request using the `appid` parameter.

Example:

```bash theme={null}
curl "https://api.openweathermap.org/data/2.5/weather?lat=48.85&lon=2.35&units=metric&appid=YOUR_API_KEY"
```

Replace `YOUR_API_KEY` with your actual API key.

## Security best practices

* Do not hardcode your API key in client-side code
* Store it in an environment variable
* Never commit your API key to version control

Example using an environment variable:

```bash theme={null}
export OPENWEATHER_API_KEY=your_api_key_here

curl "https://api.openweathermap.org/data/2.5/weather?lat=48.85&lon=2.35&units=metric&appid=$OPENWEATHER_API_KEY"
```

## Common issues

| Error              | Cause                                 | Solution                                                        |
| ------------------ | ------------------------------------- | --------------------------------------------------------------- |
| `401 Unauthorized` | Missing, invalid, or inactive API key | Check your `appid` value, activation status, and request format |