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

# Authentication

> Use public access when it is enough, and add a Polaris API key when you need broader or older data access.

You do not need an API key for every Polaris workflow. Many first-run tasks work without authentication, including public catalog access and public-window queries on some endpoints.

Add a Polaris API key when you need broader access, explicit historical ranges on restricted endpoints, or access that matches your account tier.

## When to use an API key

Use a bearer token when:

* You need explicit `from` and `to` ranges on endpoints that restrict those fields for public requests.
* You need older preview data that sits outside the public window.
* You want access that reflects your account tier.

## Bearer auth

```bash theme={null}
curl \
  -H "Authorization: Bearer pk_live_your_key" \
  "https://api.polaris.supply/trades?source=binance&market=BTC-USDT&limit=100"
```

## Where you use the API key

Use the same Polaris API key across:

* [REST API](/reference/api-reference)
* [Python SDK](/sdks/python)
* [Rust SDK](/sdks/rust)

## Authentication notes

* Public requests work for some endpoints and are the easiest place to start.
* Historical `from` and `to` queries on most data endpoints require a bearer token.
* Snapshot downloads only require bearer auth when the dataset access policy returned by `/snapshots` requires it.

<Tip>
  If you are testing access for the first time, start with the [Quickstart](/quickstart) and use the snapshots workflow before moving to higher-volume queries.
</Tip>

## Next steps

* Read [Catalog](/reference/catalog) before building market-specific requests.
* Read [API overview](/reference/api-reference) for the full endpoint map.
* Read [Python SDK](/sdks/python) or [Rust SDK](/sdks/rust) if you want a client library instead of direct HTTP requests.