> For the complete documentation index, see [llms.txt](https://gitbook-docs.coinmetrics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook-docs.coinmetrics.io/cm-api-spec/timeseries/timeseries-stream/market-open-interest.md). # Market open interest Returns a WebSocket stream of open interests for specified markets.\ If you are falling behind (slow client) you will get `warning` message first, then `error` message and disconnection will happen.\ \ Note: The `value_usd` field in this endpoint was previously calculated using hardcoded logic that no longer reflects current contract specifications across all exchanges.\ \ To address this, we have deprecated the `value_usd` field and introduced new, more accurate metrics available via the `/timeseries/market-metrics` endpoint.\ \ These two metrics should be used as a replacement for the `value_usd` field going forward:\ \- `open_interest_reported_future_usd` to represent the notional value of open interest in U.S. dollars for futures markets\ \- `open_interest_reported_option_notional_usd` to represent the notional value of open interest in U.S. dollars for options markets\ \ We also introduced `open_interest_reported_option_market_value_usd` to represent the market value of open interest in U.S. dollars for options markets. ```json {"openapi":"3.0.2","info":{"title":"Coin Metrics API v4","version":"4.0.0"},"tags":[{"name":"Timeseries stream","description":"WebSocket endpoints for getting a real-time stream of metrics, market data, indexes and other time series data.\n\n**Endpoints on this page:**\n- `GET /timeseries-stream/asset-metrics` — Asset metrics\n- `GET /timeseries-stream/asset-quotes` — Asset quotes\n- `GET /timeseries-stream/index-levels` — Index levels\n- `GET /timeseries-stream/market-candles` — Market candles\n- `GET /timeseries-stream/market-contract-prices` — Market contract prices\n- `GET /timeseries-stream/market-liquidations` — Market liquidations\n- `GET /timeseries-stream/market-openinterest` — Market open interest\n- `GET /timeseries-stream/market-orderbooks` — Market orderbooks\n- `GET /timeseries-stream/market-quotes` — Market quotes\n- `GET /timeseries-stream/market-trades` — Market trades\n- `GET /timeseries-stream/pair-quotes` — Pair quotes"}],"servers":[{"url":"wss://api.coinmetrics.io/v4"}],"security":[{"api_key":[]}],"components":{"securitySchemes":{"api_key":{"description":"Coin Metrics API key can be specified as `?api_key=` query parameter.","in":"query","name":"api_key","type":"apiKey"}},"parameters":{"MarketId":{"description":"Comma separated list of markets or market patterns like `exchange-*` or `exchange-*-spot` or `*USDT-future`.
Use a corresponding `/catalog-all-v2/market-{dataType}` endpoint for the full list of supported markets for a given data type.","in":"query","name":"markets","required":true,"schema":{"type":"array","items":{"type":"string"}},"explode":false},"Backfill":{"description":"What data should be sent upon a connection.
By default the latest values are sent just before real-time data.","in":"query","name":"backfill","schema":{"type":"string","default":"latest","enum":["latest","none"]}},"Pretty":{"description":"Human-readable formatting of JSON responses.","in":"query","name":"pretty","schema":{"type":"boolean","default":false}}},"responses":{"Unauthorized":{"description":"Requested resource requires authorization.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/ErrorResponse"}}}},"Forbidden":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/ErrorResponse"}}},"description":"Requested resource is not available with supplied credentials."},"UriTooLong":{"description":"Provided URI is too long. It must not be greater than 10000 symbols."},"StreamingMarketOpenInterests":{"description":"Open Interest WebSocket message.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/StreamingMarketOpenInterest"}}}}},"schemas":{"ErrorResponse":{"properties":{"error":{"$ref":"#/components/schemas/ErrorObject"}},"required":["error"],"type":"object"},"ErrorObject":{"properties":{"type":{"description":"Error type string. Can be used for error identification.","type":"string"},"message":{"description":"Human-friendly error description. Can be amended without prior notification. Do not use for error identification in your code.","type":"string"}},"required":["type","description"],"type":"object"},"StreamingMarketOpenInterest":{"description":"Market open interest WebSocket message.","properties":{"market":{"$ref":"#/components/schemas/MarketId"},"time":{"$ref":"#/components/schemas/Time"},"contract_count":{"$ref":"#/components/schemas/ContractCount"},"value_usd":{"deprecated":true,"$ref":"#/components/schemas/ContractValueUSD"},"exchange_time":{"$ref":"#/components/schemas/OpenInterestExchangeTime"},"cm_sequence_id":{"$ref":"#/components/schemas/cmSequenceId"}},"required":["market","time","contract_count","value_usd","cm_sequence_id"],"type":"object"},"MarketId":{"description":"Unique name of the market.","type":"string"},"Time":{"description":"The time in ISO 8601 date-time format. Always with nanoseconds precision.","type":"string","format":"date-time"},"ContractCount":{"description":"Number of contracts.","type":"string","format":"int64"},"ContractValueUSD":{"deprecated":true,"description":"Deprecated. Contract value in USD. This field was previously calculated using hardcoded logic that no longer reflects current contract specifications across all exchanges. Please use the new metrics available via `/timeseries/market-metrics` endpoint: `open_interest_reported_future_usd` for futures markets and `open_interest_reported_option_notional_usd` for options markets.","type":"string","format":"decimal"},"OpenInterestExchangeTime":{"description":"Time corresponding to open interest data point, according to the exchange. Can be NULL, if exchange doesn't support it.","type":"string","format":"date-time"},"cmSequenceId":{"description":"The monotonically increasing message number, resets on disconnection.","type":"string"}}},"paths":{"/timeseries-stream/market-openinterest":{"get":{"summary":"Market open interest","description":"Returns a WebSocket stream of open interests for specified markets.
If you are falling behind (slow client) you will get `warning` message first, then `error` message and disconnection will happen.

Note: The `value_usd` field in this endpoint was previously calculated using hardcoded logic that no longer reflects current contract specifications across all exchanges.

To address this, we have deprecated the `value_usd` field and introduced new, more accurate metrics available via the `/timeseries/market-metrics` endpoint.

These two metrics should be used as a replacement for the `value_usd` field going forward:
- `open_interest_reported_future_usd` to represent the notional value of open interest in U.S. dollars for futures markets
- `open_interest_reported_option_notional_usd` to represent the notional value of open interest in U.S. dollars for options markets

We also introduced `open_interest_reported_option_market_value_usd` to represent the market value of open interest in U.S. dollars for options markets.","operationId":"getTimeseriesStreamMarketOpenInterest","tags":["Timeseries stream"],"parameters":[{"$ref":"#/components/parameters/MarketId"},{"$ref":"#/components/parameters/Backfill"},{"$ref":"#/components/parameters/Pretty"}],"responses":{"401":{"$ref":"#/components/responses/Unauthorized"},"403":{"$ref":"#/components/responses/Forbidden"},"414":{"$ref":"#/components/responses/UriTooLong"},"default":{"$ref":"#/components/responses/StreamingMarketOpenInterests"}}}}}} ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://gitbook-docs.coinmetrics.io/cm-api-spec/timeseries/timeseries-stream/market-open-interest.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.