> ## 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.

# Apr-Basis Constant Maturity Decorated

> This endpoint returns the quoted futures basis for various exchanges, interpolated to reflect a constant days to expiration (DTE). The data also features dynamic granularity based on the selected date range.



## OpenAPI

````yaml get /analytics/futures-perpetuals/apr-basis/constant-days-to-expiration
openapi: 3.1.0
info:
  title: derivatives-api
  version: '2'
servers:
  - url: https://api.amberdata.com/markets/derivatives
security:
  - sec0: []
paths:
  /analytics/futures-perpetuals/apr-basis/constant-days-to-expiration:
    get:
      summary: Apr-Basis Constant Maturity Decorated
      description: >-
        This endpoint returns the quoted futures basis for various exchanges,
        interpolated to reflect a constant days to expiration (DTE). The data
        also features dynamic granularity based on the selected date range.
      operationId: derivatives-futures-perpetuals-apr-basis-constant-maturity-decorated
      parameters:
        - name: asset
          in: query
          description: >-
            **[Required]** The underlying currency for which there are futures
            contracts/instruments. 

            **[Examples]** ` BTC | ETH `
          required: true
          schema:
            type: string
            default: BTC
        - name: startDate
          in: query
          description: |-
            Payload only includes data after this date (inclusive). 
            **[Formats]** `seconds | milliseconds | iso8601`
            **[Examples]** `1578531600 | 1578531600000 | 2020-09-01T01:00:00`
          required: false
          schema:
            type: string
            default: '2025-11-01'
        - name: endDate
          in: query
          description: |2-
             Payload only includes data before this date (exclusive). 
            **[Formats]** `seconds | milliseconds | iso8601`
            **[Examples]** `1578531600 | 1578531600000 | 2020-09-01T01:00:00`
          required: false
          schema:
            type: string
            default: '2025-11-10'
        - name: interval
          in: query
          description: >-
            **[Required]** This interval parameter filters for the selected
            constant maturity DTE (Days To Expiration). 

            **[Examples]** ` 7D | 30D | 90D |180D`
          required: true
          schema:
            type: string
            default: 30D
        - 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
            default: hr
      responses:
        '200':
          description: '200'
          content:
            application/json:
              schema:
                type: object
                properties:
                  status:
                    type: integer
                    example: 200
                  title:
                    type: string
                    example: OK
                  description:
                    type: string
                    example: Successful request
                  payload:
                    type: object
                    properties:
                      data:
                        type: array
                        items:
                          type: object
                          properties:
                            apr:
                              type: number
                              example: 11.03
                              description: >-
                                The annualized percentage rate of the spot
                                differential
                            basis:
                              type: number
                              example: 462.6
                              description: >-
                                The absolute dollar value differential between
                                the spot price and futures price
                            daysToExpiration:
                              type: number
                              example: 30
                              description: The days to maturity value
                            symbol:
                              type: string
                              example: bybit_BTC-USDT-linear
                              description: >-
                                The instrument name, including exchange and
                                contract type
                            timestamp:
                              type: string
                              example: '1704067200000'
                              description: Timestamp for the basis and APR data point
              examples:
                Result:
                  value:
                    status: 200
                    title: OK
                    description: Successful request
                    payload:
                      data:
                        - apr: 5.140000000000001
                          basis: 462.6
                          daysToExpiration: 30
                          symbol: bybit_BTC-USDT-linear
                          timestamp: 2025-11-01 00:00:00 000
        '400':
          description: '400'
          content:
            application/json:
              examples:
                Result:
                  value: {}
              schema:
                type: object
                properties: {}
      deprecated: false
      security:
        - ApiKeyAuth: []
components:
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: x-api-key

````