> ## Documentation Index > Fetch the complete documentation index at: https://docs.stardex.com/llms.txt > Use this file to discover all available pages before exploring further. # Start an enrollment > Enrolls every `ready` person with exactly the emails stored on the batch. Pass the `version` and `summary.ready` you read, so nothing you haven't seen is sent; if either changed you get `409` and nothing is enrolled. Everyone is checked again: a person who unsubscribed or was enrolled in this campaign by someone else in the meantime is listed in `rejected_at_start` and the rest are enrolled. Calling start again is safe: it returns or finishes the first result with `replayed: true`. To undo a start, stop the batch with `POST /v1/campaigns/{id}/enrollments/stop`. Only the API key or person who created the batch can start it. Needs `campaigns:enroll`. ## OpenAPI ````yaml /api-reference/openapi-v1.json post /v1/campaigns/{id}/enrollment-batches/{batch_id}/start openapi: 3.1.0 info: title: Stardex API (v1) version: 1.0.0 description: >- Stardex ATS API — manage candidates, jobs, companies, and recruiting workflows. servers: - url: https://api.stardex.ai description: Production API server security: - bearerAuth: [] tags: - name: Persons description: Manage person records — contacts, work history, and custom fields. - name: Jobs description: Manage job postings — pipeline stages, team members, and custom fields. - name: Candidates description: Manage candidate records and pipeline stage transitions. - name: Companies description: Browse and retrieve company records. - name: Lists description: Create, search, and retrieve saved person and company lists. - name: Person Activities description: Create and manage activity records (notes, emails, meetings) for persons. - name: Team Members description: List team members for use in search filters and assignments. - name: Custom Fields description: Retrieve custom field definitions and tag options for search filters. - name: Campaigns description: >- Create and edit email campaigns, enroll people through enrollment batches, and manage who is enrolled. paths: /v1/campaigns/{id}/enrollment-batches/{batch_id}/start: post: tags: - Campaigns summary: Start an enrollment description: >- Enrolls every `ready` person with exactly the emails stored on the batch. Pass the `version` and `summary.ready` you read, so nothing you haven't seen is sent; if either changed you get `409` and nothing is enrolled. Everyone is checked again: a person who unsubscribed or was enrolled in this campaign by someone else in the meantime is listed in `rejected_at_start` and the rest are enrolled. Calling start again is safe: it returns or finishes the first result with `replayed: true`. To undo a start, stop the batch with `POST /v1/campaigns/{id}/enrollments/stop`. Only the API key or person who created the batch can start it. Needs `campaigns:enroll`. operationId: startCampaignEnrollmentBatch parameters: - schema: type: string format: uuid description: Campaign ID. required: true description: Campaign ID. name: id in: path - schema: type: string format: uuid description: Enrollment batch ID. required: true description: Enrollment batch ID. name: batch_id in: path requestBody: content: application/json: schema: $ref: '#/components/schemas/EnrollmentBatchStartRequest' example: version: 5 expected_recipient_count: 4 from_email: riya@acmetalent.com responses: '200': description: Enrolled content: application/json: schema: $ref: '#/components/schemas/EnrollmentBatchStartResponse' example: success: true data: batch_id: eb8d2f41-3c7a-4e19-b5d2-7f0a1c9e6b34 status: starting replayed: false summary: enrolled: 3 rejected_at_start: 1 not_enrolled: 1 enrollments: - person_id: 2f6b9d1e-4a8c-4e3f-b7d2-1c5a9e3b7f40 enrollment_id: e7b1d3f5-9a2c-4e6b-8d0f-3a5c7e9b1d42 first_email_estimated_at: '2026-10-19T08:00:00.000Z' - person_id: 4e8b2d6f-1a3c-4e9b-8f5d-7c2a6e1b3d95 enrollment_id: f3a5c7e9-1b3d-4f6a-8c2e-4d6f8a0c2e57 first_email_estimated_at: '2026-10-19T08:00:00.000Z' - person_id: 8f6c1d2e-3b5a-4c7e-9d1f-6a8c0e2b4d76 enrollment_id: a9c1e3f5-7b2d-4e8a-9c4f-6e8a0c2e4b18 first_email_estimated_at: '2026-10-19T08:00:00.000Z' not_enrolled: - person_id: 9c4f1a7e-2d8b-4e6c-b3a9-5f1d7c3e8b24 status: blocked rejected_at_start: - person_id: 6a3e8c2f-9b1d-4f7a-a5c3-8e2b6d4f1a73 issues: - code: person_do_not_contact message: Marked do not contact. follow_up_errors: - person_id: 4e8b2d6f-1a3c-4e9b-8f5d-7c2a6e1b3d95 message: >- Enrolled, but adding them to the job didn't finish. It is retried automatically. '400': description: Validation error content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '403': description: No access to campaigns, or the API key lacks the permission content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '404': description: Resource not found content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '409': description: >- The batch changed since you read it (BATCH_VERSION_CHANGED, RECIPIENT_COUNT_MISMATCH), is preparing or can no longer start (BATCH_PREPARING, BATCH_NOT_EDITABLE), the campaign changed or was archived (BATCH_STALE, CAMPAIGN_ARCHIVED), the scheduled start passed (START_TIME_PASSED), nobody is ready (NOTHING_TO_ENROLL), or the mailbox differs or is disconnected (SENDER_MISMATCH, MAILBOX_DISCONNECTED) content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '410': description: The draft expired 24 hours after its last change (BATCH_EXPIRED) content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '429': description: >- Daily enrollment limit reached (DAILY_ENROLLMENT_LIMIT_REACHED), or rate limited (RATE_LIMIT_EXCEEDED) content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '500': description: Internal server error content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error components: schemas: EnrollmentBatchStartRequest: type: object properties: version: type: integer minimum: 1 description: The batch version you read. Start fails if it has changed. expected_recipient_count: type: integer minimum: 0 description: >- How many people you expect to enroll: summary.ready from the batch you read. from_email: type: string format: email description: >- The mailbox you expect it to send from. When given and different from the batch, start fails with 409 SENDER_MISMATCH. required: - version - expected_recipient_count EnrollmentBatchStartResponse: type: object properties: success: type: boolean enum: - true data: $ref: '#/components/schemas/EnrollmentBatchStartResult' required: - success - data EnrollmentBatchStartResult: type: object properties: batch_id: type: string format: uuid status: type: string enum: - starting - started replayed: type: boolean description: >- True when this batch had already started and this call returned or finished that result. summary: type: object properties: enrolled: type: integer rejected_at_start: type: integer not_enrolled: type: integer required: - enrolled - rejected_at_start - not_enrolled enrollments: type: array items: type: object properties: person_id: type: string format: uuid enrollment_id: type: string format: uuid first_email_estimated_at: type: - string - 'null' required: - person_id - enrollment_id - first_email_estimated_at not_enrolled: type: array items: type: object properties: person_id: type: string format: uuid status: type: string enum: - preparing - ready - needs_input - blocked - excluded - enrolled - rejected_at_start required: - person_id - status rejected_at_start: type: array items: type: object properties: person_id: type: string format: uuid issues: type: array items: type: object properties: code: type: string description: >- Blocks: person_not_found, email_bounced, unsubscribed, person_do_not_contact, already_enrolled. Needs input: no_email, email_not_on_person, company_do_not_contact, already_enrolled_different_email, previously_completed, missing_variables, ai_generation_failed. Warnings: likely_bounce, enrolled_in_other_campaign, previously_in_campaign (was in this campaign before and was stopped, cancelled or failed). message: type: string description: What is wrong and how to fix it. details: type: object additionalProperties: anyOf: - type: string - type: number - type: boolean - type: 'null' - type: array items: type: string - type: 'null' description: Extra facts about the issue, such as variable names. required: - code - message required: - person_id - issues follow_up_errors: type: array items: type: object properties: person_id: type: string format: uuid message: type: string required: - person_id - message description: >- People who are enrolled but whose follow-up did not finish: adding them to the job (retried automatically), saving their email as preferred, or adding them as a client contact. required: - batch_id - status - replayed - summary - enrollments - not_enrolled - rejected_at_start - follow_up_errors securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- Authenticate with a Bearer token: API key, OAuth token, or session token. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.