> ## Documentation Index > Fetch the complete documentation index at: https://docs.ionworks.com/llms.txt > Use this file to discover all available pages before exploring further. # Get a project's channel-hours by state per calendar period > Return channel-hours by state for each calendar period from start to now. Each point splits the period's channel-hours into occupied, stale, free, and out of service, with the Lab wall's precedence, so it describes the whole period rather than one instant. The last point is the period in progress, computed up to now and flagged ``partial``. At most 400 points. ## OpenAPI ````yaml https://api.ionworks.com/openapi.json get /projects/{project_id}/lab/utilization-history openapi: 3.1.0 info: title: FastAPI version: 0.1.0 servers: - url: https://api.ionworks.com description: Production security: [] paths: /projects/{project_id}/lab/utilization-history: get: tags: - Lab summary: Get a project's channel-hours by state per calendar period description: >- Return channel-hours by state for each calendar period from start to now. Each point splits the period's channel-hours into occupied, stale, free, and out of service, with the Lab wall's precedence, so it describes the whole period rather than one instant. The last point is the period in progress, computed up to now and flagged ``partial``. At most 400 points. operationId: >- get_utilization_history_projects__project_id__lab_utilization_history_get parameters: - name: project_id in: path required: true schema: type: string format: uuid title: Project Id - name: start in: query required: true schema: type: string format: date-time description: >- Start of the range, ISO 8601 (a date is read as UTC midnight). Snapped back to its period's boundary; at most 3660 days ago. title: Start description: >- Start of the range, ISO 8601 (a date is read as UTC midnight). Snapped back to its period's boundary; at most 3660 days ago. - name: granularity in: query required: false schema: $ref: '#/components/schemas/UtilizationGranularity' description: Calendar period each point covers, in UTC default: month description: Calendar period each point covers, in UTC responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/UtilizationHistory' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: UtilizationGranularity: type: string enum: - day - week - month - quarter - year title: UtilizationGranularity description: The calendar period each history point covers, in UTC. UtilizationHistory: properties: project_id: type: string title: Project Id description: Project the history covers granularity: $ref: '#/components/schemas/UtilizationGranularity' description: Calendar period each point covers start: type: string format: date-time title: Start description: >- Start of the first point: the requested start snapped back to its period's boundary, or later if no channel existed yet trimmed_to_first_channel: type: boolean title: Trimmed To First Channel description: >- Whether periods before the project's first channel were dropped, so the series starts later than requested default: false generated_at: type: string format: date-time title: Generated At description: When the history was computed points: items: $ref: '#/components/schemas/UtilizationHistoryPoint' type: array title: Points description: One point per period, oldest first type: object required: - project_id - granularity - start - generated_at title: UtilizationHistory description: >- Utilization per calendar period, oldest first, ending with the current one. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError UtilizationHistoryPoint: properties: period_start: type: string format: date-time title: Period Start description: Inclusive start of the period period_end: type: string format: date-time title: Period End description: >- Exclusive end of the period; the current time for the period still in progress partial: type: boolean title: Partial description: Whether the period is still in progress default: false occupied_hours: type: number title: Occupied Hours description: Channel-hours running a test stale_hours: type: number title: Stale Hours description: >- Channel-hours of still-open runs after they stopped uploading; finished runs count as occupied throughout free_hours: type: number title: Free Hours description: Channel-hours idle and in service out_of_service_hours: type: number title: Out Of Service Hours description: Channel-hours under an outage available_hours: type: number title: Available Hours description: Channel-hours of channels that existed during the period utilization_percent: type: number title: Utilization Percent description: Occupied plus stale over available — the wall's headline rule utilization_of_available_percent: type: number title: Utilization Of Available Percent description: Occupied plus stale over the hours not out of service type: object required: - period_start - period_end - occupied_hours - stale_hours - free_hours - out_of_service_hours - available_hours - utilization_percent - utilization_of_available_percent title: UtilizationHistoryPoint description: >- Channel-hours by state over one calendar period. The four state hours partition ``available_hours`` with the Lab wall's precedence: out of service, then stale, then occupied, then free. A channel contributes only from when it existed — the earlier of its ``created_at`` and its first run. Stale is known only for runs still open (see the service). ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.