# Bridge stream · HyperEVM API · Femtos

> Each HyperCore ↔ HyperEVM transfer, initiated then completed.

- 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/hyperevm/ws-bridge

WebSocket: get a ticket (`POST https://api.femtos.xyz/v1/ws-ticket` with your key), connect to `wss://api.femtos.xyz/v1/ws?ticket=$TICKET`, send the frame below; the first message has `"snapshot": true`. Details: https://femtos.xyz/agents.md#websocket

## Bridge stream — WS `bridge.transfers`

Each HyperCore ↔ HyperEVM transfer, initiated then completed.

| Param | In | Example or values |
|---|---|---|
| `token` | filter | (optional) |
| `direction` | filter | `(empty)`, `evm_to_core`, `core_to_evm` |

```json
{"op":"subscribe","channel":"bridge.transfers","filter":{}}
```

| Field | Type | Meaning |
|---|---|---|
| `snapshot: true` | object[] | last 50 transfers |
| `data` | object | one transfer in its new state (core_evm row shape) |

## Related (Bridge & wallet)

- [Bridge transfers](https://femtos.xyz/hyperevm/bridge.md): HyperCore ↔ HyperEVM transfers (core_evm) or HyperEVM ↔ Elysium movements (evm_elysium), with 24 h stats.
- [Bridge coverage](https://femtos.xyz/hyperevm/bridge-coverage.md): Every HyperCore ↔ HyperEVM leg since our data starts, paired with its other leg: matched share per direction and token, why the others are not, latency.
- [Cross-layer wallet](https://femtos.xyz/hyperevm/wallet.md): One address (or a named wallet's handle) on HyperCore, HyperEVM and Elysium, plus its latest events.

All HyperEVM endpoints: https://femtos.xyz/hyperevm.md