> ## Documentation Index > Fetch the complete documentation index at: https://docs.useboom.ai/llms.txt > Use this file to discover all available pages before exploring further. # List participants > List an initiative's participants and the values Boom captured from each, newest first. Each row carries both contact identifiers (`phoneNumber`, `email`) — on an email initiative the phone is null for everyone, so read the one the initiative actually sends to. Filter by personExternalId to find one person's runs — including the live one, to stop it before starting another. ## OpenAPI ````yaml /api-reference/openapi.json get /api/v1/initiatives/{id}/participants openapi: 3.1.0 info: title: Boom API version: 1.0.0 description: >- Boom's public REST API — one uniform surface over every platform capability. CDP: upsert people and custom objects, define object and relationship types, link and unlink relationships, and record behavioral events — one record per request or up to 1000 per request via the `/batch` endpoints. Segments: read (list, read, membership) and full authoring — discover the filterable catalog, validate a filter, create and update segments, preview match counts, and trigger evaluation. Initiatives: create and configure outreach initiatives, link WhatsApp templates, drive the lifecycle (launch, cancel, archive), and read collected-data summaries. Participants: enroll people into an active initiative, track their status, read conversation transcripts, and stop outreach. Journeys: read-only access to always-on message flows and their metrics. WhatsApp templates: list your WhatsApp numbers and list, read, and create message templates. The same capabilities are exposed as MCP tools with identical schemas. servers: - url: https://www.useboom.ai description: Production - url: https://dev.useboom.ai description: Development (sandbox — use a development organization API key) security: - bearerAuth: [] paths: /api/v1/initiatives/{id}/participants: get: tags: - Initiatives summary: List participants description: >- List an initiative's participants and the values Boom captured from each, newest first. Each row carries both contact identifiers (`phoneNumber`, `email`) — on an email initiative the phone is null for everyone, so read the one the initiative actually sends to. Filter by personExternalId to find one person's runs — including the live one, to stop it before starting another. operationId: initiatives_participants_list parameters: - name: id in: path required: true schema: $schema: https://json-schema.org/draft/2020-12/schema type: string minLength: 1 description: Initiative id. - name: personExternalId in: query required: false schema: $schema: https://json-schema.org/draft/2020-12/schema description: >- Return only this person's runs, matched on the external id recorded when the run started. Exact match, case-sensitive. Participants enrolled without an external id are never returned, so an empty result means no run carries this id — not that the person has no run. type: string minLength: 1 maxLength: 255 - name: limit in: query required: false schema: $schema: https://json-schema.org/draft/2020-12/schema description: Page size, up to 1000. type: integer minimum: 1 maximum: 1000 - name: cursor in: query required: false schema: $schema: https://json-schema.org/draft/2020-12/schema description: Opaque cursor from a previous page. type: string responses: '200': description: Success content: application/json: schema: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: data: type: array items: type: object properties: participantId: type: string phoneNumber: anyOf: - type: string - type: 'null' email: anyOf: - type: string - type: 'null' description: >- The participant's email, when one is on record. Null on a WhatsApp-only roster, and the only identifier on an email initiative's — which is why a caller cannot assume `phoneNumber` identifies a row. name: anyOf: - type: string - type: 'null' status: type: string enum: - ACTIVE - COMPLETED - STOPPED - EXPIRED - FAILED description: >- ACTIVE (conversation may still happen), COMPLETED, STOPPED (messaging halted), EXPIRED, or FAILED. messageCount: anyOf: - type: number - type: 'null' createdAt: type: string description: ISO 8601 timestamp. capturedAt: anyOf: - type: string - type: 'null' description: When values were last captured (ISO 8601), if any. extractionStatus: anyOf: - type: string - type: 'null' description: >- PENDING (queued, not yet run), EXTRACTED (ran and wrote), INSUFFICIENT_DATA (nothing extractable here — too few messages or no reply on THIS initiative), FAILED, or null for a participant whose extraction has never been triggered. INSUFFICIENT_DATA does NOT mean the person never replied: check their other initiatives with scope="customer" on the messages endpoint. values: type: object propertyNames: type: string additionalProperties: type: array items: type: string description: Captured values, keyed by variable key. required: - participantId - phoneNumber - email - name - status - messageCount - createdAt - capturedAt - extractionStatus - values additionalProperties: false next_cursor: anyOf: - type: string - type: 'null' required: - data - next_cursor additionalProperties: false '400': description: Validation failed or the request cannot proceed. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '401': description: Missing, malformed, or revoked API key. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '404': description: The resource does not exist in this organization. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '409': description: >- Conflicts with the current state (duplicates, wrong lifecycle state). content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '422': description: The request is well-formed but semantically invalid. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '429': description: Rate limit exceeded — retry after `Retry-After`. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '500': description: Internal server error. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error '503': description: Transient error — retry with a narrower request. content: application/json: schema: type: object properties: error: type: object properties: code: type: string description: Stable machine-readable error code (snake_case). message: type: string required: - code - message required: - error components: securitySchemes: bearerAuth: type: http scheme: bearer description: 'Organization API key, sent as `Authorization: Bearer boom_org_...`.' ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.