# Hyperliquid WS · HyperCore API · Femtos

> Hyperliquid’s WebSocket subscriptions, served from our node.

- 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` (or `X-API-KEY: $FEMTOS_KEY`). Free key: https://femtos.xyz/accounts/ (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/hypercore/hl-ws

## Hyperliquid WS — WS `/ws`

Hyperliquid’s WebSocket subscriptions, served from our node.

Same frames as `wss://api.hyperliquid.xyz/ws`, on `wss://api.femtos.xyz/ws?token=$FEMTOS_KEY`.

| Field | Type | Meaning |
|---|---|---|
| `{"method":"subscribe","subscription":{…}}` | frame | same frames as api.hyperliquid.xyz/ws |
| `trades · l2Book · candle · allMids · bbo` | type | market subscriptions |
| `userFills · orderUpdates` | type | one account |

## Related (Hyperliquid-compatible)

- [POST /info](https://femtos.xyz/hypercore/info.md): Hyperliquid’s /info request bodies, answered from our node.

All HyperCore endpoints: https://femtos.xyz/hypercore.md