> ## Documentation Index > Fetch the complete documentation index at: https://fal.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Metrics > Returns Prometheus-compatible metrics in text format for integration into your observability stack **Authentication:** Required - Uses API key authentication **Format:** Returns text/plain in Prometheus exposition format **Common Use Cases:** - Export app stats to your observability provider (grafana, datadog etc) - Track runner health and performance - Set up alerts and monitoring See [Prometheus documentation](https://prometheus.io/docs/instrumenting/exposition_formats/) for format details. ## OpenAPI ````yaml /api-reference/platform-apis/openapi/v1.json get /serverless/metrics openapi: 3.1.0 info: title: Platform APIs version: v1 description: fal REST API for programmatic access to platform resources. servers: - url: https://api.fal.ai/v1 description: Production server security: [] paths: /serverless/metrics: get: tags: - Serverless - Metrics - Observability summary: Metrics description: >- Returns Prometheus-compatible metrics in text format for integration into your observability stack **Authentication:** Required - Uses API key authentication **Format:** Returns text/plain in Prometheus exposition format **Common Use Cases:** - Export app stats to your observability provider (grafana, datadog etc) - Track runner health and performance - Set up alerts and monitoring See [Prometheus documentation](https://prometheus.io/docs/instrumenting/exposition_formats/) for format details. operationId: serverlessGetMetrics responses: '200': description: Prometheus-compatible metrics retrieved successfully content: text/plain: schema: type: string description: Prometheus-compatible metrics in text format example: |- # HELP fal_app_queue_size Current size of the fal app queue # TYPE fal_app_queue_size gauge fal_requests_total{application="my/app"} 10 example: >- # HELP fal_app_runners Number of fal app runners # TYPE fal_app_runners gauge fal_app_runners{application="my/app",machine_type="NVIDIA B200",state="running"} 21 # HELP fal_app_queue_size Current size of the fal app queue # TYPE fal_app_queue_size gauge fal_app_queue_size{application="my/app"} 7 # HELP fal_app_concurrent_requests Current number of concurrent requests being processed # TYPE fal_app_concurrent_requests gauge fal_app_concurrent_requests{application="my/app"} 3 # HELP fal_app_requests_completed Number of requests completed in the last minute # TYPE fal_app_requests_completed gauge fal_app_requests_completed{application="my/app",method="POST",status="200"} 18 # HELP fal_app_requests_received Number of requests received in the last minute # TYPE fal_app_requests_received gauge fal_app_requests_received{application="my/app",method="POST"} 24 # HELP fal_app_request_latency Number of requests completed, bucketed by latency in seconds # TYPE fal_app_request_latency gauge fal_app_request_latency{application="my/app",le="1.0"} 5 fal_app_request_latency{application="my/app",le="+Inf"} 24 '401': description: Authentication required content: application/json: schema: type: object properties: error: type: object properties: type: type: string enum: - authorization_error - validation_error - not_found - rate_limited - server_error - not_implemented description: The category of error that occurred message: type: string description: Human-readable error message docs_url: type: string format: uri description: Link to relevant documentation request_id: type: string description: Unique request identifier for debugging required: - type - message description: Error details required: - error description: Standard error response format example: error: type: authorization_error message: Authentication required '429': description: Rate limit exceeded content: application/json: schema: type: object properties: error: type: object properties: type: type: string enum: - authorization_error - validation_error - not_found - rate_limited - server_error - not_implemented description: The category of error that occurred message: type: string description: Human-readable error message docs_url: type: string format: uri description: Link to relevant documentation request_id: type: string description: Unique request identifier for debugging required: - type - message description: Error details required: - error description: Standard error response format example: error: type: rate_limited message: Rate limit exceeded '500': description: Internal server error content: application/json: schema: type: object properties: error: type: object properties: type: type: string enum: - authorization_error - validation_error - not_found - rate_limited - server_error - not_implemented description: The category of error that occurred message: type: string description: Human-readable error message docs_url: type: string format: uri description: Link to relevant documentation request_id: type: string description: Unique request identifier for debugging required: - type - message description: Error details required: - error description: Standard error response format example: error: type: server_error message: An unexpected error occurred security: - apiKey: [] components: securitySchemes: apiKey: type: apiKey in: header name: Authorization description: >- API key must be prefixed with "Key ", e.g. Authorization: Key YOUR_API_KEY ````