Thatch Employer onboarding sessions API

openapi: 3.1.0
info:
  title: Thatch for Platforms Deductions Employer onboarding sessions API
  version: v1
  description: Thatch for Platforms is a set of REST APIs and embeddable JavaScript components that let partners bring ICHRA (Individual Coverage Health Reimbursement Arrangement) benefits to their customers. Partners onboard employers, manage employees, run the employer onboarding flow through an embedded iframe, track enrollments and members, model pay schedules, and retrieve payroll deductions. Access is limited to approved partners; contact platforms@thatch.com to set up an account and generate an API key in the Thatch dashboard.
  contact:
    name: Thatch for Platforms
    email: platforms@thatch.com
    url: https://docs.thatch.com/
  x-apisjson-generated: '2026-07-21'
  x-apisjson-method: generated
  x-apisjson-source: https://docs.thatch.com/api/
servers:
- url: https://partners.thatchcloud.com/api/partners/v1
  description: Production
security:
- Bearer: []
tags:
- name: Employer onboarding sessions
  description: Employers onboard into a platform through employer onboarding sessions. After creating a session, provide the claim_url to the onboarding iframe in your app.
paths:
  /employer_onboarding_sessions:
    post:
      tags:
      - Employer onboarding sessions
      operationId: createEmployerOnboardingSession
      summary: Create an employer onboarding session
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - employer
              properties:
                employer:
                  type: string
                  description: ID of the employer to create an onboarding session for
                email:
                  type: string
                  description: Email address of the admin to create the session for. When provided, a User and EmployerAdmin are created (or found) for this email.
                first_name:
                  type: string
                  description: First name of the admin (used when creating a new EmployerAdmin via email)
                last_name:
                  type: string
                  description: Last name of the admin (used when creating a new EmployerAdmin via email)
      responses:
        '201':
          description: Create an employer onboarding session
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmployerOnboardingSession'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    EmployerOnboardingSession:
      type: object
      properties:
        employer:
          type: string
          example: empl_01j2j3smtwx656y2tbqm7ty6gr
        employer_admin_email:
          type: string
          example: admin@example.com
        claim_url:
          type: string
          description: URL to provide to the onboarding iframe.
          example: https://app.thatch.com/employer_onboarding_sessions/SR86rPsHKWp02FivyQ6Z4hgUN0VBz6RR/claim
        expires_at:
          type: string
          format: date-time
  responses:
    Unauthorized:
      description: Authentication failed or API key missing/invalid.
  securitySchemes:
    Bearer:
      type: http
      scheme: bearer
      description: 'All requests are authenticated with your API key using Bearer token authentication. Include the header `Authorization: Bearer <YOUR_API_KEY>`. Generate an API key in the Thatch dashboard.'