Open Interest

Real-time futures Open Interest stream. Subscribe to any {symbol}@{exchange} pair to receive every update the collector observes. Futures-only (spot Open Interest does not exist).

Connect

websocat

websocat wss://api.datamaxiplus.com/ws/v1/open-interest -H 'X-DTMX-APIKEY: $YOUR_API_KEY'

wscat

wscat -c wss://api.datamaxiplus.com/ws/v1/open-interest -H 'X-DTMX-APIKEY: $YOUR_API_KEY'

Subscribe

params is a list of {symbol}@{exchange} entries. symbol is the exchange-native API symbol (e.g. BTC-USDT on Bybit). Invalid pairs are silently dropped — the ack echoes back only what passed validation.

schema

{ "method": "SUBSCRIBE", "params": [ string ], "id": int32 }

example

{
  "method": "SUBSCRIBE",
  "params": ["BTC-USDT@bybit", "ETH-USDT@okx"],
  "id": 1
}

Response

Each update is a full Open Interest snapshot for a single pair. protojson-encoded — keys match the short JSON names from the protobuf schema.

Field	Description
id	TokenId — Internal unified token id
e	Exchange — e.g. bybit
d	Timestamp — Exchange-reported time in ms (UTC)
s	Symbol — Exchange-native API symbol
b	Base — e.g. BTC
q	Quote — e.g. USDT
oi	OpenInterest — Open Interest in base units
oiusd	OpenInterestUsd — Open Interest in USD (optional, missing if no price)

Example

{
  "id": "bitcoin",
  "e": "bybit",
  "d": 1776826789123,
  "s": "BTC-USDT",
  "b": "BTC",
  "q": "USDT",
  "oi": 98432.5,
  "oiusd": 7500123456.7
}

Ping / Keepalive

Send {"method":"PING"} periodically to keep the connection alive.

Pricing

Each successful subscribe request costs 1 credit regardless of how many pairs are in params. Connection itself is free.