> ## 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. # Send a one-time code > Send a one-time code over WhatsApp to a phone number or a known person (`personExternalId`). WhatsApp writes the message text, and the expiry comes from the authentication template chosen on the dashboard. Calling again while the code is still valid resends the same code with the same `otpId` (`resent: true`). Returns 429 with `retryAfterSeconds` inside the resend cooldown or over the hourly per-number cap. People sharing a phone get separate codes when `personExternalId` or `reference` is passed. ## OpenAPI ````yaml /api-reference/openapi.json post /api/v1/otp/send 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/otp/send: post: tags: - One-time codes summary: Send a one-time code description: >- Send a one-time code over WhatsApp to a phone number or a known person (`personExternalId`). WhatsApp writes the message text, and the expiry comes from the authentication template chosen on the dashboard. Calling again while the code is still valid resends the same code with the same `otpId` (`resent: true`). Returns 429 with `retryAfterSeconds` inside the resend cooldown or over the hourly per-number cap. People sharing a phone get separate codes when `personExternalId` or `reference` is passed. operationId: otp_send requestBody: required: true content: application/json: schema: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: phone: type: string minLength: 1 description: Recipient phone in E.164 format, e.g. +5215512345678. personExternalId: type: string minLength: 1 description: Your own ID for the person; Boom uses their stored phone. reference: type: string maxLength: 255 description: >- Your label for what the code is for, e.g. an appointment ID. People sharing a phone get separate codes when this or `personExternalId` is passed. responses: '200': description: Success content: application/json: schema: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: otpId: type: string description: Pass this to otp_verify. status: type: string const: PENDING expiresAt: type: string description: ISO 8601 timestamp. resent: type: boolean description: True when an existing valid code was sent again. reference: anyOf: - type: string - type: 'null' personExternalId: anyOf: - type: string - type: 'null' required: - otpId - status - expiresAt - resent - reference - personExternalId 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.