API reference, Liquidations & positions
Open interest per block
The open interest of a perp after every block with a fill: longs and shorts opened, closed, liquidated. One frame per block with all its matching events.
- Elysium: not served
- HyperCore
- HyperEVM: not served
- Not on Elysium or HyperEVM: a channel of HyperCore only
WebSocket channel hc.oi on wss://api.femtos.xyz/v1/ws
Parameters
| Param | In | Example or values | Meaning |
|---|---|---|---|
coin | filter | BTC | HyperCore market (BTC, @107, xyz:TSLA) |
Subscribe
{"op":"subscribe","channel":"hc.oi","filter":{"coin":"BTC"}}Key: Authorization: Bearer $FEMTOS_KEY. Get a free key, or with no browser through agent onboarding.
Response fields
| Field | Type | Meaning |
|---|---|---|
snapshot: true | HcOi[] | the latest state of each perp (of the coin asked) |
data | HcOi[] | the open interest of each perp after each block with a fill, with what moved it: one frame per HyperCore block, `data` the block's matching events in order (a block with none sends nothing): {coin, block, time, oi, d, long_open, long_close, short_open, short_close, taker_long_open, taker_short_open, liq, …} |
data[].oi | decimal | Open interest after the block (size, longs and shorts together) |
data[].d | decimal | Its change in the block |
data[].long_open | decimal | Size of longs opened in the block |
data[].liq | decimal | Size closed on liquidated accounts |
batch | "block" | every live frame: one block, `data` its matching events |
Related: Liquidations & positions
- Liquidations GET /v1/liquidations HyperCore
Perp liquidations, newest first, one row per account, coin and block. - Liquidations stream WS hc.liquidations HyperCore
Each liquidation fill, the block it happens. One frame per block with all its matching events. - Liquidation stats GET /v1/liquidations/stats HyperCore
Totals, per coin, per time bucket and the largest, over a window. - Liquidation stats stream WS hc.liquidations.stats HyperCore
The GET /v1/liquidations/stats answer (totals, per coin, per bucket, the largest), pushed on subscribe, then when a liquidation comes in (whole, or as a JSON Patch). - Positions GET /v1/positions HyperCore
Open positions of one perp with leverage and liquidation price. - Position changes WS hc.positions HyperCore
Each perp position change, one per block, account and coin. One frame per block with all its matching events. - Open positions stream WS hc.positions.open HyperCore
The GET /v1/positions answer of one perp (size, entry, PnL, leverage, liquidation price), pushed on subscribe, then on each roll of the live positions (every 5 s) when it changes. - Position change history GET /v1/positions/changes HyperCore
Past perp position changes of one coin over a size, one row per account and block. - Open interest GET /v1/positions/overview HyperCore
Open interest, accounts and unrealized PnL per perp. - Open interest stream WS hc.positions.overview HyperCore
The GET /v1/positions/overview answer (long / short open interest, accounts, unrealized PnL per perp), pushed on subscribe, then on each roll of the live positions (every 5 s) when it changes (whole, or as a JSON Patch). - Liquidation map GET /v1/positions/liqmap HyperCore
Notional that would be liquidated at each price around the mark. - Liquidation levels stream WS hc.positions.liqmap HyperCore
The GET /v1/positions/liqmap answer of one perp (notional liquidated per price bucket), pushed on subscribe, then on each roll of the live positions (every 5 s) when it changes. - Open interest history GET /v1/hypercore/oi HyperCore
Open interest bars of a perp since May 2023, after every block since March 2025: longs and shorts opened, closed, liquidated. - Open interest by market GET /v1/hypercore/oi/markets HyperCore
Every perp's open interest now, its 1 h / 24 h / 7 d change, totals per dex. - Open interest by position size GET /v1/hypercore/oi/cohorts HyperCore
Long and short open interest of a perp by position size, every hour since September 2025. - Who opened positions GET /v1/hypercore/oi/opens HyperCore
The largest orders that opened longs or shorts on a perp in a window, with the account and whether it crossed the spread.
More
- This page as Markdown
- The whole API reference
- What HyperCore serves
- The whole API in one Markdown file
- OpenAPI 3.1 document
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