> ## Documentation Index > Fetch the complete documentation index at: https://docs.apollodeploy.com/llms.txt > Use this file to discover all available pages before exploring further. # Get topic engagement analytics > Returns delivery and engagement performance for one topic over the selected time window. API-key authentication always uses the key's project; `projectId` is only needed for dashboard-session authentication. ### Requirements - **Permission:** `emails:send` or `emails:read` or `metrics:read`. - **HTTP rate limit:** 120 requests per 60 seconds per API key. ## OpenAPI ````yaml /signal/api-reference/openapi.json get /v1/metrics/topics/{id} openapi: 3.1.0 info: title: Apollo Signal API version: 1.0.0 description: >- Public REST API for transactional email, contacts, audiences, webhooks, metrics, projects, and sending domains. servers: - url: https://api.signal.apollodeploy.com description: Production security: [] tags: - name: Emails description: Send, inspect, cancel, validate, and stream transactional email activity. - name: Metrics description: Read project, topic, message, and deliverability analytics. - name: Suppressions description: Manage addresses that Apollo Signal must not send to. - name: Segments description: Create dynamic contact groups and inspect their membership. - name: Topics description: Manage subscription topics and topic membership. - name: Contact properties description: Define the custom fields available on project contacts. - name: Contacts description: >- Manage contacts, audience membership, images, activity, and engagement data. - name: Webhooks description: Manage webhook endpoints, deliveries, tests, and replays. - name: API key usage description: Inspect API key metadata and request usage without exposing raw keys. - name: Projects description: Inspect projects and project-scoped email logs. - name: Sending domains description: >- Register, verify, inspect, and remove sending domains and BIMI configuration. paths: /v1/metrics/topics/{id}: get: tags: - Metrics summary: Get topic engagement analytics description: >- Returns delivery and engagement performance for one topic over the selected time window. API-key authentication always uses the key's project; `projectId` is only needed for dashboard-session authentication. ### Requirements - **Permission:** `emails:send` or `emails:read` or `metrics:read`. - **HTTP rate limit:** 120 requests per 60 seconds per API key. operationId: getTopicPerformance parameters: - name: id in: path required: true deprecated: false explode: false schema: type: string title: String description: Topic identifier. - name: window in: query description: 'Time window: `24h`, `7d`, `30d` (default), `90d`.' required: false deprecated: false explode: false schema: type: string title: String - name: projectId in: query description: Required for session auth; ignored for API key auth. required: false deprecated: false explode: false schema: type: string title: String responses: '200': headers: {} content: application/json: schema: $ref: >- #/components/schemas/com.apollodeploy.signal.feature.metrics.api.model.TopicPerformanceResponse description: Request completed successfully. '401': headers: {} content: application/problem+json: schema: $ref: >- #/components/schemas/com.apollodeploy.commons.core.error.ApiProblem description: >- The API key or stream token is missing, invalid, expired, or inactive. '403': description: >- The credential lacks the required permission or cannot access this project. headers: {} content: application/problem+json: schema: $ref: >- #/components/schemas/com.apollodeploy.commons.core.error.ApiProblem '404': headers: {} content: application/problem+json: schema: $ref: >- #/components/schemas/com.apollodeploy.commons.core.error.ApiProblem description: The requested resource was not found in the authenticated project. '429': description: >- The endpoint rate limit was exceeded. Wait for the `Retry-After` interval before retrying. headers: Retry-After: description: Whole seconds to wait before retrying. schema: type: integer minimum: 1 content: application/problem+json: schema: $ref: >- #/components/schemas/com.apollodeploy.commons.core.error.ApiProblem deprecated: false security: - bearerAuth: [] components: schemas: com.apollodeploy.signal.feature.metrics.api.model.TopicPerformanceResponse: type: object properties: avgReadTimeSeconds: type: number format: double title: Double bounceRate: type: number format: double title: Double bounced: type: integer format: int32 title: Int clickRate: type: number format: double title: Double clicked: type: integer format: int32 title: Int complained: type: integer format: int32 title: Int complaintRate: type: number format: double title: Double computedAt: type: string title: String delivered: type: integer format: int32 title: Int deliveryRate: type: number format: double title: Double openRate: type: number format: double title: Double opened: type: integer format: int32 title: Int optInCount: type: integer format: int64 title: Long optOutCount: type: integer format: int64 title: Long readEngaged: type: integer format: int32 title: Int readEngagementRate: type: number format: double title: Double topicId: type: string title: String topicName: type: string title: String totalEmails: type: integer format: int32 title: Int unsubscribeRate: type: number format: double title: Double unsubscribed: type: integer format: int32 title: Int window: $ref: >- #/components/schemas/com.apollodeploy.signal.feature.metrics.api.model.MetricsWindowResponse required: - bounceRate - bounced - clickRate - clicked - complained - complaintRate - computedAt - delivered - deliveryRate - openRate - opened - optInCount - optOutCount - readEngaged - readEngagementRate - topicId - topicName - totalEmails - unsubscribeRate - unsubscribed - window title: TopicPerformanceResponse com.apollodeploy.commons.core.error.ApiProblem: type: object properties: code: type: string title: ErrorCode detail: type: string title: String errors: type: array items: $ref: >- #/components/schemas/com.apollodeploy.commons.core.error.FieldProblem title: List instance: type: string title: ProblemInstance requestId: type: string title: String status: type: integer format: int32 title: Int title: type: string title: String type: type: string title: ProblemType required: - code - status - title - type title: ApiProblem com.apollodeploy.signal.feature.metrics.api.model.MetricsWindowResponse: type: object properties: from: type: string title: String label: type: string title: String to: type: string title: String required: - from - label - to title: MetricsWindowResponse com.apollodeploy.commons.core.error.FieldProblem: type: object properties: detail: type: string title: String pointer: type: string title: String required: - detail - pointer title: FieldProblem securitySchemes: bearerAuth: type: http scheme: bearer description: >- Project-bound Apollo Signal API key. Keys begin with `ap_signal_` and must carry the permission shown on the operation. ````