# Liquidity events · Elysium API · Femtos

> Liquidity added to and removed from one pool, newest first.

- 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/liquidity

## Liquidity events — GET `/v1/liquidity`

Liquidity added to and removed from one pool, newest first.

| Param | In | Example or values |
|---|---|---|
| `layer` | query | `elysium` |
| `pair` | query | `0x889a96eedb1df35a012d7e48baf7f9c780f1243b:0xfd93e1ba852feba3f05d7089513049c168a87fd058f64f4eb15f1c0bd3534467` |
| `limit` | query | `20` |

```bash
curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/liquidity?layer=elysium&pair=0x889a96eedb1df35a012d7e48baf7f9c780f1243b%3A0xfd93e1ba852feba3f05d7089513049c168a87fd058f64f4eb15f1c0bd3534467&limit=20"
```

| Field | Type | Meaning |
|---|---|---|
| `rows[]` | object | {block, t, tx, kind: add \| remove, provider, amount0, amount1, usd} |
| `liquidityDelta · tickLower · tickUpper` | string · int | V4: the event carries a liquidity delta, no token amounts |
| `token0 · token1` | object | {address, symbol, decimals} |

## Related (Market data)

- [Candles](https://femtos.xyz/elysium/candles.md): OHLCV of one pool in pair price, USD and market cap, ascending, UTC-aligned.
- [Forming candle](https://femtos.xyz/elysium/ws-candles.md): The forming candle, pushed once per block where it changes.
- [Trades](https://femtos.xyz/elysium/trades.md): Latest swaps of one pool, newest first.
- [Trades stream](https://femtos.xyz/elysium/ws-trades.md): The swaps of one pool, one message per block that has some.
- [Daily token volume](https://femtos.xyz/elysium/volume.md): USD swap volume of a token per UTC day, both sides of every priced swap. Testnet pool prices.
- [Token transfers](https://femtos.xyz/elysium/transfers.md): ERC-20 Transfer events of one token, newest first.

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