> ## Documentation Index
> Fetch the complete documentation index at: https://docs.endstate.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Generate an e-value for a test chip

> Returns a fresh `e` value for a test chip. POST the returned `e` to `/v1/chips/{chip_id}` to test your integration end-to-end. Only valid for test chips.



## OpenAPI

````yaml /openapi.json post /v1/chips/{chip_id}/tap
openapi: 3.1.0
info:
  title: Endstate API
  version: v1
  description: Endstate developer API for chip verification and ownership workflows.
servers:
  - url: https://api2.endstate.io
    description: Production
security: []
paths:
  /v1/chips/{chip_id}/tap:
    post:
      tags:
        - Chips
      summary: Generate an e-value for a test chip
      description: >-
        Returns a fresh `e` value for a test chip. POST the returned `e` to
        `/v1/chips/{chip_id}` to test your integration end-to-end. Only valid
        for test chips.
      parameters:
        - schema:
            type: string
            pattern: ^[0-9A-F]{10}$
            description: Chip identifier.
            example: ABCDEF0123
          required: true
          name: chip_id
          in: path
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/TapChipRequest'
            example:
              count: 5
      responses:
        '200':
          description: Generated e-value and count.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TapChipResponse'
              example:
                chip_id: ABCDEF0123
                e: C78566198547116F3A715DC1C62AF96F
                count: 5
      security:
        - ApiKeyBearer: []
components:
  schemas:
    TapChipRequest:
      type: object
      properties:
        count:
          type: integer
          minimum: 0
          description: >-
            Optional counter value. Defaults to the next emulated chip counter
            and reserves it, so each tap returns a new e-value. Explicit counts
            must be greater than the chip's current highestObservedCount.
          example: 5
    TapChipResponse:
      type: object
      properties:
        chip_id:
          type: string
          example: ABCDEF0123
        e:
          type: string
          example: C78566198547116F3A715DC1C62AF96F
        count:
          type: integer
          minimum: 0
          example: 5
      required:
        - chip_id
        - e
        - count
  securitySchemes:
    ApiKeyBearer:
      type: http
      scheme: bearer
      bearerFormat: end_sk
      description: >-
        Use `Authorization: Bearer end_sk_*` for partner API keys (e.g.
        `end_sk_AbCd_example_api_key`).

````