# Quickstart | Femtos

> Femtos quickstart: get a free API key with your email, make your first call to the Hyperliquid data API, then pick REST, WebSocket or MCP.

- Base URL: `https://api.femtos.xyz/v1` (REST) · `wss://api.femtos.xyz/v1/ws` (WebSocket) · MCP: `https://api.femtos.xyz/mcp`
- Auth: `Authorization: Bearer $FEMTOS_KEY`. Free key: https://dashboard.femtos.xyz/signup (browser), or with
  no browser: `GET https://femtos.xyz/accounts/agent/challenge`, solve its proof of work, then `POST https://femtos.xyz/accounts/agent/signup`
  (https://femtos.xyz/agents.md#agent-onboarding)
- Decimals are exact strings, times Unix milliseconds, addresses lowercase `0x`
- Whole API in one file: https://femtos.xyz/agents.md · OpenAPI: https://api.femtos.xyz/v1/openapi.json · Index: https://femtos.xyz/llms.txt
- Page with live calls: https://femtos.xyz/docs/quickstart

Get a key, make a call, then pick what to build on.

## 1. Get an API key

Enter your email on https://dashboard.femtos.xyz/signup. A new address gets its key at once, with free monthly credits. An agent signs itself up: https://femtos.xyz/setup.md.

## 2. Make your first call

List every HyperCore market with its 24 h stats. Send the key as a Bearer token.

```bash
curl -s "https://api.femtos.xyz/v1/markets?layer=hypercore" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

## 3. Pick what to build on

- [API reference](https://femtos.xyz/reference.md): every call and channel, with a live example.
- [WebSocket streams](https://femtos.xyz/reference/ws/trades.md): data pushed as it happens.
- [MCP for agents](https://femtos.xyz/mcp.md): let an agent query the data.