# Twelve Data auth.md — Authentication

Twelve Data uses API key authentication. OAuth is not used for API access.

## Getting an API key

1. Register at https://twelvedata.com/register — the Basic plan is free and requires no credit card.
2. Your API key is shown in the dashboard: https://twelvedata.com/account/api-keys

## Using the API key

The REST API base URL is `https://api.twelvedata.com`. Pass the key in one of two ways:

As a query parameter:

```
GET https://api.twelvedata.com/price?symbol=AAPL&apikey=your_api_key
```

Or as a header:

```
Authorization: apikey your_api_key
```

The WebSocket endpoint `wss://ws.twelvedata.com` and the hosted MCP server `https://mcp.twelvedata.com` use the same API key.

## Errors and limits

- `401` — missing or invalid API key.
- `429` — rate limit exceeded; request frequency and credit limits depend on the plan (see https://twelvedata.com/pricing).
- Most endpoints cost 1 API credit per symbol; premium data (fundamentals, analysis) costs more.

## More information

- Documentation: https://twelvedata.com/docs
- Documentation for LLMs: https://twelvedata.com/docs/llms.txt
- OpenAPI specification: https://api.twelvedata.com/doc/swagger/openapi.json
- API catalog: https://twelvedata.com/.well-known/api-catalog