Open Interest

Real-time futures open interest (OI) stream. Subscribe to {symbol}@{exchange} pairs and receive every update the collector observes. Futures only — spot does not have open interest.

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's native API symbol (e.g. Bybit's BTC-USDT). Invalid pairs are silently dropped; the ack returns only those that 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 an open interest snapshot for a single pair. protojson-encoded — keys use the short JSON names from the protobuf schema.

Schema

Schema

idstring

internal unified token id

estring

e.g. bybit

dinteger

exchange-reported time (ms, UTC)

sstring

exchange-native API symbol

bstring

e.g. BTC

qstring

e.g. USDT

oinumber

open interest in base asset units

oiusdnumber

USD-converted open interest (omitted if no price available)

oifiatnumber

open interest converted to the requested fiat/quote currency (optional)

Example

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

Ping / Keepalive

Connection keepalive is server-managed — the server sends WebSocket protocol Ping frames every 30 seconds and standard WebSocket libraries respond with Pong automatically. Clients do not need to send an application-level {"method":"PING"} to stay connected.

See WebSocket API › Ping for details.

Pricing

Each subscribe request is billed 1 credit regardless of how many pairs are in params. The connection itself is free.