# Documentation | Femtos

> Femtos documentation: get started, the three layers (HyperCore, HyperEVM, Elysium), real-time streams and webhooks, the Hyperliquid-compatible API, MCP and files for agents.

- 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

Query Hyperliquid data on HyperCore, HyperEVM and Elysium over REST, WebSocket and MCP.

## Get started

- [Quickstart](https://femtos.xyz/docs/quickstart.md): Get a key and make your first call in under a minute.
- [Plans and limits](https://femtos.xyz/docs/plans.md): Free monthly credits, what a call costs, pay as you go or a plan, and the rate limits.
- [API reference](https://femtos.xyz/reference.md): Every REST call and WebSocket channel with its parameters and fields.
- [Changelog](https://femtos.xyz/changelog.md): What changed in the API, newest first.

## Layers

- [HyperCore](https://femtos.xyz/hypercore.md): Order book, perps, spot, HIP-3 markets, liquidations, positions and stops on the Hyperliquid exchange.
- [HyperEVM](https://femtos.xyz/hyperevm.md): DEX pools, swaps, tokens, holders, NFTs, LiquidLaunch launches and wallet history on the Hyperliquid EVM chain.
- [Elysium](https://femtos.xyz/elysium.md): Ascend launches, PancakeSwap Infinity pools, holders and new tokens on the Kinetiq L2.
- [Launch story](https://femtos.xyz/hyperevm/lifecycle.md): Follow one token launch event by event: dev wallet, early buyers, swaps, holders.

## Real time

- [WebSocket streams](https://femtos.xyz/reference/ws/trades.md): Subscribe to trades, books, liquidations and launches as they happen.
- [Webhooks](https://femtos.xyz/webhooks): Get bridges, wallet activity, liquidations and launches sent to your HTTPS URL, signed and retried.
- [Hyperliquid-compatible](https://femtos.xyz/reference/hl/info.md): Point an existing Hyperliquid client at Femtos and keep your code.

## Agents

- [MCP for agents](https://femtos.xyz/mcp.md): Let Claude, Cursor and other agents query the data with no code.
- [agents.md](https://femtos.xyz/agents.md): The whole API in one Markdown file for coding agents.
- [OpenAPI](https://femtos.xyz/api/openapi.json): The OpenAPI document of the REST API, to generate a client.