# Lifecycle stage changes · Elysium API · Femtos

> A message when a launched token reaches its next stage: listing desk, HyperEVM mirror, HyperCore spot, perp.

- 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/elysium/ws-ascend-lifecycle

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

## Lifecycle stage changes — WS `ascend.lifecycle`

A message when a launched token reaches its next stage: listing desk, HyperEVM mirror, HyperCore spot, perp.

| Param | In | Example or values |
|---|---|---|
| `token` | filter | (optional) |

```json
{"op":"subscribe","channel":"ascend.lifecycle","filter":{}}
```

| Field | Type | Meaning |
|---|---|---|
| `snapshot: true` | object[] | {kind: snapshot, stages: {token: [stages]}}, or the lifecycle of `token` |
| `data.kind` | stage | a launched token reached or lost a stage |
| `data.reached · data.lost` | string[] | stages since the previous poll |
| `data.stage · data.previous` | string | current and previous last stage |
| `data.lifecycle` | object | as GET /api/tokens/{token}/lifecycle |

## Related (Lifecycle)

- [Launch timeline](https://femtos.xyz/elysium/timeline.md): The whole life of a launch as ordered events with running state.
- [Token across layers](https://femtos.xyz/elysium/token-lifecycle.md): One token from its Elysium launch to its HyperEVM mirror, HyperCore spot and perps, each link proven or marked inferred.

All Elysium endpoints: https://femtos.xyz/elysium.md