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

# Authentication

> Authenticating requests to the StellarTools API

Every request to the StellarTools API must include your API key in the `x-api-key` header.

```bash theme={null}
curl https://api.stellartools.dev/customers \
  -H "x-api-key: YOUR_API_KEY"
```

The API key determines the environment your requests run in. Keys prefixed for testnet only interact with testnet data; mainnet keys interact with live data. There is no separate base URL — the key controls it.

## Getting an API key

Go to [dashboard.stellartools.dev/api-keys](https://dashboard.stellartools.dev/api-keys) to create and manage your keys. Copy the key immediately after creating it — it will not be shown again.

```bash theme={null}
STELLAR_TOOLS_API_KEY=sk_test_...
```

Store it in an environment variable and never expose it in client-side code.

## Errors

If the key is missing, the API returns `401`:

```json theme={null}
{ "error": "Session Token or API Key or App Token required" }
```

If the key is present but invalid or revoked, the API returns `401` as well. Double-check that you are sending the right key for the right environment (testnet vs. mainnet).