> ## Documentation Index > Fetch the complete documentation index at: https://docs.amberdata.io/llms.txt > Use this file to discover all available pages before exploring further. # Delta Surfaces Constant > This endpoint returns the option delta surface with constant maturities. USA Trading hours are 14:30:00 - 21:00:00 UTC (9:30a-4pm ET) ## OpenAPI ````yaml get /analytics/volatility/delta-surfaces/constant/tradfi openapi: 3.1.0 info: title: derivatives-api version: '2' servers: - url: https://api.amberdata.com/markets/derivatives security: - sec0: [] paths: /analytics/volatility/delta-surfaces/constant/tradfi: get: summary: Delta Surfaces Constant description: | This endpoint returns the option delta surface with constant maturities. USA Trading hours are 14:30:00 - 21:00:00 UTC (9:30a-4pm ET) operationId: tradfi-volatility-delta-surfaces-constant parameters: - name: currency in: query description: > **[Required]** The underlying currency for which there are listed option instruments. **[Examples]** `IBIT | COIN` required: true schema: type: string default: IBIT - name: startDate in: query description: > **[Optional]** Payload only includes data after this date (inclusive). **[Formats]** `seconds | milliseconds | iso8601` **[Examples]** `1578531600 | 1578531600000 | 2024-11-19T15:00:00` schema: type: string format: date-time - name: endDate in: query description: > **[Optional]** Payload only includes data before this date (exclusive). **[Formats]** `seconds | milliseconds | iso8601` **[Examples]** `1578531600 | 1578531600000 | 2024-11-20T15:00:00` schema: type: string format: date-time - name: daysToExpirationStart in: query description: > **[Optional]** Users can pass a days to expiration filter lower bound, to return only a subset of the delta surface. **[Examples]** `0 | 7 | 60` schema: type: integer format: int32 - name: daysToExpirationEnd in: query description: > **[Optional]** Users can pass a days to expiration filter upper bound, to return only a subset of the delta surface. **[Examples]** `1 | 30 | 180 | 600` schema: type: integer format: int32 - name: timeInterval in: query description: > **[Optional]** Time interval of data frequency for the selected date range. **[Examples]** `minute | hour | day` **[Note]** Due to the density of data historical date ranges are limited to 60x 1-minute or 24x 1 hour intervals, per call. schema: type: string - name: timeFormat in: query description: > **[Optional]** Time format of the timestamps in the return payload. **[Defaults]** `milliseconds | ms* | iso | iso8601 | hr | human_readable` schema: type: string responses: '200': description: Successful request content: application/json: schema: type: object properties: status: type: integer example: 200 default: 0 title: type: string example: OK description: type: string example: Successful request payload: type: object properties: data: type: array items: type: object properties: atm: type: number example: 60.21999716758728 currency: type: string example: IBIT daysToExpiration: type: integer example: 5 deltaCall10: type: number example: 60.9220027923584 deltaCall20: type: number example: 61.36699914932251 deltaCall30: type: number example: 61.97400093078613 deltaCall40: type: number example: 63.96600008010864 deltaPut10: type: number example: 60.882002115249634 deltaPut20: type: number example: 59.411001205444336 deltaPut30: type: number example: 59.10099744796753 deltaPut40: type: number example: 59.76099967956543 exchange: type: string example: tradfi indexPrice: type: number example: 53.134998 multiplier: type: integer example: 100 timestamp: type: string example: '2024-11-19T17:40:00.000Z' metadata: type: object properties: api-version: type: string example: '2023-09-30' examples: success_response: summary: TradFi delta surfaces response value: status: 200 title: OK description: Successful request payload: data: - atm: 60.21999716758728 currency: IBIT daysToExpiration: 5 deltaCall10: 60.9220027923584 deltaCall20: 61.36699914932251 deltaCall30: 61.97400093078613 deltaCall40: 63.96600008010864 deltaPut10: 60.882002115249634 deltaPut20: 59.411001205444336 deltaPut30: 59.10099744796753 deltaPut40: 59.76099967956543 exchange: tradfi indexPrice: 53.134998 multiplier: 100 timestamp: '2024-11-19T17:40:00.000Z' - atm: 60.21999716758728 currency: IBIT daysToExpiration: 10 deltaCall10: 60.9220027923584 deltaCall20: 61.36699914932251 deltaCall30: 61.97400093078613 deltaCall40: 63.96600008010864 deltaPut10: 60.882002115249634 deltaPut20: 59.411001205444336 deltaPut30: 59.10099744796753 deltaPut40: 59.76099967956543 exchange: tradfi indexPrice: 53.134998 multiplier: 100 timestamp: '2024-11-19T17:40:00.000Z' - atm: 60.21999716758728 currency: IBIT daysToExpiration: 21 deltaCall10: 60.9220027923584 deltaCall20: 61.36699914932251 deltaCall30: 61.97400093078613 deltaCall40: 63.96600008010864 deltaPut10: 60.882002115249634 deltaPut20: 59.411001205444336 deltaPut30: 59.10099744796753 deltaPut40: 59.76099967956543 exchange: tradfi indexPrice: 53.134998 multiplier: 100 timestamp: '2024-11-19T17:40:00.000Z' - atm: 64.92000222206116 currency: IBIT daysToExpiration: 42 deltaCall10: 65.82099795341492 deltaCall20: 66.56699776649475 deltaCall30: 68.02800297737122 deltaCall40: 73.07699918746948 deltaPut10: 65.6059980392456 deltaPut20: 61.677998304367065 deltaPut30: 61.215001344680786 deltaPut40: 62.882000207901 exchange: tradfi indexPrice: 53.134998 multiplier: 100 timestamp: '2024-11-19T17:40:00.000Z' metadata: api-version: '2023-09-30' '400': description: Bad request content: application/json: schema: type: object properties: {} examples: error_response: summary: Bad request example value: {} deprecated: false security: - ApiKeyAuth: [] components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key ````