> ## Documentation Index > Fetch the complete documentation index at: https://docs.rails.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Contracts Stream > Contract definitions with live mark price, IV, and Greeks. This stream is available on the `optionsContracts` subscription. It provides option contract definitions with live mark price, implied volatility, and Greeks, scoped by **underlying** and **expiration date**. #### Snapshot vs. Update The `emitOptionsContracts` request returns the full set of contracts for an underlying and expiration date via `optionsContracts`. Once subscribed, `optionsContractUpdate` messages stream price, IV, and Greek changes per contract. See [Pricing & Greeks](/latest/options/guides/pricing-and-greeks) for how the Greeks are computed. ## AsyncAPI ````yaml latest/options/asyncapi/options-ws.yaml contractsStream id: contractsStream title: Contracts Stream description: > Available on the `optionsContracts` subscription. Contract definitions with live mark price, implied volatility, and Greeks, scoped by underlying and expiration date. servers: - id: sandbox protocol: wss host: ws.sandbox.rails.xyz bindings: [] variables: [] address: >- ?product=options&market={market}&expiration={expiration}&strike={strike}&type={type}&subscriptions=optionsContracts parameters: - id: market jsonSchema: type: string description: A specific market (e.g. `BTC-USDT`) or `ALL`. default: BTC-USDT description: A specific market (e.g. `BTC-USDT`) or `ALL`. type: string required: true deprecated: false - id: expiration jsonSchema: type: string description: >- Contract expiration, e.g. `24JUN26`. Requires `market`; omit to match every expiration. default: 24JUN26 description: >- Contract expiration, e.g. `24JUN26`. Requires `market`; omit to match every expiration. type: string required: true deprecated: false - id: strike jsonSchema: type: string description: >- Strike price, e.g. `62000`. Requires `expiration`; omit to match every strike. default: '62000' description: >- Strike price, e.g. `62000`. Requires `expiration`; omit to match every strike. type: string required: true deprecated: false - id: type jsonSchema: type: string description: '`C` (call) or `P` (put). Requires `strike`; omit to match both.' default: C description: '`C` (call) or `P` (put). Requires `strike`; omit to match both.' type: string required: true deprecated: false bindings: [] operations: - &ref_1 id: emitOptionsContracts title: Emit options contracts description: Request the full set of contracts for an underlying and expiration date. type: receive messages: - &ref_4 id: emitOptionsContractsRequest contentType: application/json payload: - name: Emit Options Contracts type: object properties: - name: message type: string description: Always `emitOptionsContracts`. required: true - name: content type: object required: true properties: - name: clientRequestId type: string description: Client-generated UUID for correlation required: false - name: underlying type: string description: >- Underlying asset (bare symbol, not paired with a quote currency), e.g. `BTC` required: true - name: expirationDate type: string description: Expiration date, `YYYY-MM-DD` required: true - name: pageSize type: integer description: Page size for paginated results required: false - name: pageToken type: string description: Cursor for the next page required: false headers: [] jsonPayloadSchema: type: object properties: message: type: string description: Always `emitOptionsContracts`. x-parser-schema-id: content: type: object properties: clientRequestId: type: string format: uuid description: Client-generated UUID for correlation x-parser-schema-id: underlying: type: string description: >- Underlying asset (bare symbol, not paired with a quote currency), e.g. `BTC` x-parser-schema-id: expirationDate: type: string description: Expiration date, `YYYY-MM-DD` x-parser-schema-id: pageSize: type: integer description: Page size for paginated results x-parser-schema-id: pageToken: type: string description: Cursor for the next page x-parser-schema-id: required: - underlying - expirationDate x-parser-schema-id: required: - message - content x-parser-schema-id: title: Emit Options Contracts example: |- { "message": "emitOptionsContracts", "content": { "clientRequestId": "ec5e9e21-e4dd-47dd-af9b-345b2b3ea976", "underlying": "BTC", "expirationDate": "2026-07-10" } } bindings: [] extensions: - id: x-parser-unique-object-id value: emitOptionsContractsRequest bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: contractsStream - &ref_2 id: optionsContractsSnapshot title: Options contracts snapshot description: Response to `emitOptionsContracts`. type: send messages: - &ref_5 id: optionsContractsResponse contentType: application/json payload: - name: Contracts Snapshot description: Response to `emitOptionsContracts`. type: object properties: - name: resultType type: string description: Always `optionsContracts`. required: true - name: market type: string description: Underlying asset (echoes the request `underlying`) required: true - name: data type: object required: true properties: - name: clientRequestId type: string description: Client-generated UUID for correlation required: false - name: contracts type: array description: Contract definitions required: true properties: - name: contractName type: string description: Contract name required: true - name: underlying type: string description: >- Underlying market paired with its quote currency, e.g. `BTC-USDT` (requests take the bare asset symbol, e.g. `BTC`) required: true - name: strike type: string description: Strike price required: true - name: optionType type: string description: Call or put enumValues: - C - P required: true - name: expiryDate type: string description: Expiry date (`YYYY-MM-DD`) required: true - name: markPrice type: string description: Mark price required: true - name: bidPrice type: string description: Best bid price required: true - name: askPrice type: string description: Best ask price required: true - name: bidSize type: string description: Best bid size required: true - name: askSize type: string description: Best ask size required: true - name: markIV type: string description: Mark implied volatility required: true - name: bidIV type: string description: >- Implied volatility at the best bid; may be empty when that side has no firm quote required: true - name: askIV type: string description: >- Implied volatility at the best ask; may be empty when that side has no firm quote required: true - name: forward type: string description: Forward price required: true - name: delta type: string description: >- Rate of change of the option's price per $1 move in the underlying required: true - name: gamma type: string description: Rate of change of delta per $1 move in the underlying required: true - name: vega type: string description: >- Sensitivity of the option's price to a 1-point change in implied volatility required: true - name: theta type: string description: >- Sensitivity of the option's price to the passage of one day required: true - name: rho type: string description: >- Sensitivity of the option's price to a 1% change in interest rates required: true - name: openInterest type: string description: Open interest required: true - name: volume24h type: string description: 24h traded volume required: true - name: expiries type: array description: Expected price move per expiry required: true properties: - name: expiryDate type: string description: Expiry date (`YYYY-MM-DD`) required: true - name: underlying type: string description: Underlying market, e.g. `BTC-USDT` required: true - name: atmIV type: string description: At-the-money implied volatility for this expiry required: true - name: expectedPriceMove type: string description: Expected move of the index price by this expiry required: true - name: indexPrice type: string description: Index price the expected move is measured from required: true - name: statusCode type: integer description: Always `200`. required: true headers: [] jsonPayloadSchema: type: object properties: resultType: type: string description: Always `optionsContracts`. x-parser-schema-id: market: type: string description: Underlying asset (echoes the request `underlying`) x-parser-schema-id: data: type: object properties: clientRequestId: type: string description: Client-generated UUID for correlation x-parser-schema-id: contracts: type: array description: Contract definitions items: type: object properties: contractName: type: string description: Contract name x-parser-schema-id: underlying: type: string description: >- Underlying market paired with its quote currency, e.g. `BTC-USDT` (requests take the bare asset symbol, e.g. `BTC`) x-parser-schema-id: strike: type: string description: Strike price x-parser-schema-id: optionType: type: string enum: - C - P description: Call or put x-parser-schema-id: expiryDate: type: string description: Expiry date (`YYYY-MM-DD`) x-parser-schema-id: markPrice: type: string description: Mark price x-parser-schema-id: bidPrice: type: string description: Best bid price x-parser-schema-id: askPrice: type: string description: Best ask price x-parser-schema-id: bidSize: type: string description: Best bid size x-parser-schema-id: askSize: type: string description: Best ask size x-parser-schema-id: markIV: type: string description: Mark implied volatility x-parser-schema-id: bidIV: type: string description: >- Implied volatility at the best bid; may be empty when that side has no firm quote x-parser-schema-id: askIV: type: string description: >- Implied volatility at the best ask; may be empty when that side has no firm quote x-parser-schema-id: forward: type: string description: Forward price x-parser-schema-id: delta: type: string description: >- Rate of change of the option's price per $1 move in the underlying x-parser-schema-id: gamma: type: string description: Rate of change of delta per $1 move in the underlying x-parser-schema-id: vega: type: string description: >- Sensitivity of the option's price to a 1-point change in implied volatility x-parser-schema-id: theta: type: string description: >- Sensitivity of the option's price to the passage of one day x-parser-schema-id: rho: type: string description: >- Sensitivity of the option's price to a 1% change in interest rates x-parser-schema-id: openInterest: type: string description: Open interest x-parser-schema-id: volume24h: type: string description: 24h traded volume x-parser-schema-id: required: - contractName - underlying - strike - optionType - expiryDate - markPrice - bidPrice - askPrice - bidSize - askSize - markIV - bidIV - askIV - forward - delta - gamma - vega - theta - rho - openInterest - volume24h x-parser-schema-id: ContractSnapshotEntry x-parser-schema-id: expiries: type: array description: Expected price move per expiry items: type: object properties: expiryDate: type: string description: Expiry date (`YYYY-MM-DD`) x-parser-schema-id: underlying: type: string description: Underlying market, e.g. `BTC-USDT` x-parser-schema-id: atmIV: type: string description: At-the-money implied volatility for this expiry x-parser-schema-id: expectedPriceMove: type: string description: Expected move of the index price by this expiry x-parser-schema-id: indexPrice: type: string description: Index price the expected move is measured from x-parser-schema-id: required: - expiryDate - underlying - atmIV - expectedPriceMove - indexPrice x-parser-schema-id: ExpiryExpectedMove x-parser-schema-id: statusCode: type: integer description: Always `200`. x-parser-schema-id: required: - contracts - expiries - statusCode x-parser-schema-id: required: - resultType - market - data x-parser-schema-id: title: Contracts Snapshot description: Response to `emitOptionsContracts`. example: |- { "resultType": "optionsContracts", "market": "BTC", "data": { "clientRequestId": "ec5e9e21-e4dd-47dd-af9b-345b2b3ea976", "contracts": [ { "contractName": "BTC-10JUL26-63000-C", "underlying": "BTC-USDT", "strike": "63000", "optionType": "C", "expiryDate": "2026-07-10", "markPrice": "1334.5252004", "bidPrice": "749.89", "askPrice": "751.71", "bidSize": "8", "askSize": "4", "markIV": "0.3899", "bidIV": "0.4178", "askIV": "0.4185", "forward": "63654.9041377805", "delta": "0.6089291", "gamma": "0.0001548", "vega": "2443.5719736", "theta": "-130.4974464", "rho": "-13.346896", "openInterest": "0", "volume24h": "0" }, { "contractName": "BTC-10JUL26-63000-P", "underlying": "BTC-USDT", "strike": "63000", "optionType": "P", "expiryDate": "2026-07-10", "markPrice": "699.9441769", "bidPrice": "1626.58", "askPrice": "1627.55", "bidSize": "4", "askSize": "4", "markIV": "0.3899", "bidIV": "0.5033", "askIV": "0.5037", "forward": "63654.9041377805", "delta": "-0.3910709", "gamma": "0.0001548", "vega": "2443.5719736", "theta": "-130.4974464", "rho": "-7.000304", "openInterest": "2", "volume24h": "0" } ], "expiries": [ { "expiryDate": "2026-07-10", "underlying": "BTC-USDT", "atmIV": "0.3899", "expectedPriceMove": "5225.80", "indexPrice": "63450.00" } ] } } bindings: [] extensions: - id: x-parser-unique-object-id value: optionsContractsResponse bindings: [] extensions: *ref_0 - &ref_3 id: optionsContractUpdate title: Options contract update description: Pushed as a contract's price, IV, and Greeks change. type: send messages: - &ref_6 id: optionsContractUpdate contentType: application/json payload: - name: Contract Update description: Pushed as a contract's price, IV, and Greeks change. type: object properties: - name: resultType type: string description: Always `optionsContractUpdate`. required: true - name: market type: string description: Contract name required: true - name: data type: object required: true properties: - name: contractName type: string description: Contract name required: true - name: underlying type: string description: >- Underlying market paired with its quote currency, e.g. `BTC-USDT` required: true - name: strike type: string description: Strike price required: true - name: optionType type: string description: Call or put enumValues: - C - P required: true - name: expiryDate type: string description: Expiry date (`YYYY-MM-DD`) required: true - name: markPrice type: string description: Mark price required: true - name: markIV type: string description: Mark implied volatility required: true - name: forward type: string description: Forward price required: true - name: delta type: string description: >- Rate of change of the option's price per $1 move in the underlying required: true - name: gamma type: string description: Rate of change of delta per $1 move in the underlying required: true - name: vega type: string description: >- Sensitivity of the option's price to a 1-point change in implied volatility required: true - name: theta type: string description: >- Sensitivity of the option's price to the passage of one day required: true - name: rho type: string description: >- Sensitivity of the option's price to a 1% change in interest rates required: true headers: [] jsonPayloadSchema: type: object properties: resultType: type: string description: Always `optionsContractUpdate`. x-parser-schema-id: market: type: string description: Contract name x-parser-schema-id: data: type: object properties: contractName: type: string description: Contract name x-parser-schema-id: underlying: type: string description: >- Underlying market paired with its quote currency, e.g. `BTC-USDT` x-parser-schema-id: strike: type: string description: Strike price x-parser-schema-id: optionType: type: string enum: - C - P description: Call or put x-parser-schema-id: expiryDate: type: string description: Expiry date (`YYYY-MM-DD`) x-parser-schema-id: markPrice: type: string description: Mark price x-parser-schema-id: markIV: type: string description: Mark implied volatility x-parser-schema-id: forward: type: string description: Forward price x-parser-schema-id: delta: type: string description: >- Rate of change of the option's price per $1 move in the underlying x-parser-schema-id: gamma: type: string description: Rate of change of delta per $1 move in the underlying x-parser-schema-id: vega: type: string description: >- Sensitivity of the option's price to a 1-point change in implied volatility x-parser-schema-id: theta: type: string description: Sensitivity of the option's price to the passage of one day x-parser-schema-id: rho: type: string description: >- Sensitivity of the option's price to a 1% change in interest rates x-parser-schema-id: required: - contractName - underlying - strike - optionType - expiryDate - markPrice - markIV - forward - delta - gamma - vega - theta - rho x-parser-schema-id: required: - resultType - market - data x-parser-schema-id: title: Contract Update description: Pushed as a contract's price, IV, and Greeks change. example: |- { "resultType": "optionsContractUpdate", "market": "BTC-10JUL26-55000-C", "data": { "contractName": "BTC-10JUL26-55000-C", "underlying": "BTC-USDT", "strike": "55000", "optionType": "C", "expiryDate": "2026-07-10", "markPrice": "8810.9085883", "markIV": "0.6571", "forward": "63794.6796692", "delta": "0.9889426", "gamma": "0.0000069", "vega": "185.7490523", "theta": "-16.6912762", "rho": "-88.2604965" } } bindings: [] extensions: - id: x-parser-unique-object-id value: optionsContractUpdate bindings: [] extensions: *ref_0 sendOperations: - *ref_1 receiveOperations: - *ref_2 - *ref_3 sendMessages: - *ref_4 receiveMessages: - *ref_5 - *ref_6 extensions: - id: x-parser-unique-object-id value: contractsStream securitySchemes: - id: wsAuth name: Sec-WebSocket-Protocol type: httpApiKey description: Supply as `authorization#` during the WebSocket handshake. in: header extensions: [] ````