API reference, Liquidations & positions

Open interest stream

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).

• Elysium: not served
• HyperCore
• HyperEVM: not served

• Not on Elysium or HyperEVM: a channel of HyperCore only

WebSocket channel hc.positions.overview on wss://api.femtos.xyz/v1/ws

Subscribe

{"op":"subscribe","channel":"hc.positions.overview","filter":{}}

Key: Authorization: Bearer $FEMTOS_KEY. Get a free key, or with no browser through agent onboarding.

Response fields

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.
• 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 per block WS hc.oi HyperCore
  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.
• 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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