> ## Documentation Index > Fetch the complete documentation index at: https://howto.paigeme.dev/llms.txt > Use this file to discover all available pages before exploring further. # Create + save a reusable audience segment > Saves the filter under a name you can reuse as `segment_id` when assembling a broadcast. A project is capped at 100 segments, and names must be unique (`409`). **Required scope:** `broadcasts:manage` ## OpenAPI ````yaml /api-reference/openapi.json post /v1/segments openapi: 3.1.0 info: title: Paige API version: 1.0.0 description: >- The Paige public REST API (`/v1`). Build WhatsApp automations against your Paige project: send messages, manage templates, read conversations, tag contacts, assemble broadcasts, edit bot code + flows, and register signed webhooks. ## Authentication Every `/v1` request authenticates with a project API key: `Authorization: Bearer pk_live_…`. Mint and scope keys in **Settings → API keys**. A key carries its own project context, so `/v1` paths never include a project id. ## Scopes Each endpoint requires one or more scopes (see each operation, and the `x-required-scopes` extension). Grant a key only the scopes it needs. A key missing a required scope gets `403 insufficient_scope`. ## Response envelope Success: `{ "success": true, "data": … }`. Error: `{ "success": false, "error": { "code", "message" }, "request_id" }`. Some errors add `error.details` with structured extras (e.g. `quota_exceeded` carries `limit` + `resetAt`) — read it defensively, its keys depend on the code. The `request_id` is also returned as the `X-Request-Id` header on every response. ## Rate limits & quota Requests are throttled per key (`RateLimit-*` headers; exceed → `429 rate_limited`). WhatsApp sends also draw down a daily quota (exceed → `429 quota_exceeded`). Both carry `Retry-After`. ## Idempotency Send an `Idempotency-Key` header on `POST /v1/messages` to make retries safe — a completed key replays the stored response and never re-sends. ## Webhook signatures Outbound webhook deliveries carry `X-Paige-Signature: t=,v1=`. Verify with the reference `verifyPaigeSignature` helper (constant-time HMAC over `"."`, 300s tolerance). contact: name: Paige url: https://paigeme.dev servers: - url: https://api.paigeme.dev description: Production security: - ApiKeyAuth: [] tags: - name: Meta description: Smoke / diagnostics. - name: Messages description: Send messages and read delivery status + media. - name: Conversations description: List conversations, read messages, set state. - name: Contacts description: Read contact messages; update names, tags, attributes. - name: Templates description: WhatsApp message template CRUD. - name: Broadcasts description: Segments + broadcast assembly (always pending_approval). - name: Build description: Read/edit bot code, deploy, read/generate/update flows. - name: Webhooks description: Register signed outbound webhooks. paths: /v1/segments: post: tags: - Broadcasts summary: Create + save a reusable audience segment description: >- Saves the filter under a name you can reuse as `segment_id` when assembling a broadcast. A project is capped at 100 segments, and names must be unique (`409`). **Required scope:** `broadcasts:manage` operationId: createSegment parameters: - schema: type: string description: >- Target project id, for an MCP OAuth bearer (`mcp_at_…`) attached to more than one project — get ids from `GET /v1/projects`. Matched case-insensitively. Omit it and a READ falls back to the connection's default project; a **mutation** (any non-GET) on a connection with 2+ projects is rejected with `400 project_required` — a write is never defaulted to a guessed project. A connection with exactly one project never needs the header. Scopes are checked against the SELECTED project only, never a union across the connection. For a `pk_` API key the header selects nothing — one key is one project's context — but it IS validated: omit it and the key's own project is used, send it and it must name that project, otherwise the call is rejected with `403 project_not_attached` (a blank value is `400 invalid_project_header`, as above). required: false name: X-Paige-Project in: header requestBody: required: true content: application/json: schema: type: object properties: name: type: string minLength: 1 maxLength: 255 filter: type: object properties: opted_in: type: boolean tags: type: array items: type: string clicked: anyOf: - type: string - type: object additionalProperties: {} name_contains: type: string number_contains: type: string include_ids: type: array items: anyOf: - type: number - type: string required: - name responses: '201': description: Success. content: application/json: schema: type: object properties: success: type: boolean enum: - true data: type: object properties: segment: type: object properties: id: type: string description: >- Pass this as `segment_id` when assembling a broadcast. project_id: type: string name: type: string filter: type: object properties: {} description: The normalized filter, as stored. contact_count: type: - number - 'null' description: >- Live count when the segment was written. NULL means the count could not be resolved — the segment is still saved and re-counts on read. created_at: type: string updated_at: type: string required: - id - project_id - name - filter - contact_count - created_at - updated_at required: - segment required: - success - data '400': description: >- Validation / bad request (e.g. `invalid_request`, `invalid_cursor`, `outside_24h_window` is 409). Also `invalid_project_header` (any credential: `X-Paige-Project` was sent but blank) and, for multi-project MCP bearers, `project_required` (a mutation, or a read with no default, and no `X-Paige-Project`). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: >- Missing or invalid API key (`api_key_required` / `invalid_api_key` / `invalid_token` for a revoked or expired OAuth bearer). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: >- Key lacks the required scope, project inactive, or a write targets a platform-protected file (`insufficient_scope` / `project_inactive` / `subscription_inactive` / `protected_file`). Also `project_not_attached` (the `X-Paige-Project` project is not one this credential may act on — not attached to the MCP connection, or not the `pk_` key's own project; identical response whether or not it exists) and, for MCP bearers, `no_project_access` (the connection has no projects attached). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '409': description: >- Conflict — 24h window closed (`outside_24h_window`) or idempotency (`idempotency_in_progress` / `idempotency_key_mismatch`). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '429': description: >- Rate limit (`rate_limited`) or daily send quota (`quota_exceeded`) exceeded. Carries `RateLimit-*` + `Retry-After` headers. headers: RateLimit-Limit: description: Requests permitted in the current window. schema: type: integer RateLimit-Remaining: description: Requests remaining in the current window. schema: type: integer RateLimit-Reset: description: Seconds until the window resets. schema: type: integer Retry-After: description: Seconds to wait before retrying. schema: type: integer content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Unexpected server error (`server_error`). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - ApiKeyAuth: [] components: schemas: ErrorResponse: type: object properties: success: type: boolean enum: - false error: $ref: '#/components/schemas/ApiError' request_id: type: string description: Per-request id, also returned as the X-Request-Id header. required: - success - error - request_id ApiError: type: object properties: code: type: string description: Stable, machine-readable error code. example: invalid_request message: type: string description: Human-readable message (safe to surface). example: Invalid request body details: type: object properties: {} description: >- Structured extras for codes that carry them — the keys depend on `code`. `quota_exceeded` carries `limit` + `resetAt`; most errors omit this field entirely. required: - code - message securitySchemes: ApiKeyAuth: type: http scheme: bearer bearerFormat: API key description: >- Project API key issued in Settings → API keys. Send it as `Authorization: Bearer pk_live_…`. ````