> ## Documentation Index > Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt > Use this file to discover all available pages before exploring further. # Get Experiment Metrics > Get per-evaluator aggregate metrics for an experiment. Auto-detects each evaluator's chart type based on score cardinality: numeric_range (>10 distinct numeric values, histogram), numeric_categorical (<=10 distinct numeric values, distribution bars), or categorical (label-only scores, distribution with ratios). ## OpenAPI ````yaml GET /v3/evals/experiments/{experiment_id}/metrics openapi: 3.0.3 info: title: Fiddler API - 2.0 description: APIs to interact with Fiddler termsOfService: https://fiddler.ai/about/terms contact: email: support@fiddler.ai license: name: Proprietary url: '2.0' version: '2.0' servers: [] security: - BearerAuth: [] tags: - name: access-key description: CRUD operations for API keys - name: span-v3 - name: aggregation-invalidation-request-v3 description: Endpoints related to retrieving aggregation invalidation requests - name: alert-rules-v3 description: CRUD for Alert Rules, Summary, and Stats APIs - name: application-v3 - name: attribute-v3 - name: auth description: Authentication strategies and login flows - name: baseline-v3 description: CRUD for baseline - name: catalog-v3 description: >- Entity catalog provides paginated, searchable discovery of entity names (attribute keys, agent names, span types, span names) and their distinct values. Powered by ClickHouse materialized views — no worker or PostgreSQL dependency. - name: chart-annotation-v3 description: Endpoints related to retrieving chart annotations - name: chart-v3 description: CRUD for chart - name: queries-v3 description: v3 queries API - name: configuration-v3 description: CRUD for configurations - name: custom-metrics-v3 - name: dimensionality-reduction-v3 - name: environment-v3 description: Endpoints related to environment management - name: evals - name: datasets - name: evaluation-v3 - name: evaluator-v3 - name: rule-evaluators-v3 - name: experiment-v3 - name: explainability-v3 - name: llm_rca-v3 - name: file-upload description: Endpoints related to file uploading. - name: fql-expressions-v3 description: > Endpoints for listing FQL (Fiddler Query Language) functions available for GenAI custom metrics. Used by the frontend for autocomplete and signature hints in the FQL editor. - name: genai-alert-rules-v3 description: CRUD API for GenAI Alert Rules - name: genai-custom-metrics-v3 description: API for GenAI Custom Metrics - name: genai-metrics-v3 description: >- Endpoints for pre-aggregated GenAI metrics. All metric data is pre-aggregated by an hourly ClickHouse refreshable materialized view; no real-time aggregation is performed at request time. - name: guardrails-api description: Endpoints related to retrieving Guardrails specific data - name: ingestion-v3 - name: intercom-api description: Endpoints related to intercom APIs - name: jobs-v3 - name: llm-gateway-v3 - name: auth-login - name: auth-logout - name: metrics-v3 description: Metrics endpoints - name: model-v3 - name: dashboard-v3 - name: model-deployment-v3 - name: monitoring-summary-v3 - name: histograms-v3 - name: organization-roles-v3 description: Update user org role - name: organization-settings-v3 description: Update organization settings such as timezone, email configuration, etc. - name: pagerduty-api description: CRUD for Pagerduty services. - name: project-v3 - name: project-roles-v3 description: Project role assignment management - name: searchable-text-key-v3 description: >- Manage the global searchable text keys table that controls which OTel attribute keys are routed to the full-text-searchable `ValueContent` column in the unified attributes table. Changes propagate to the backing ClickHouse dictionary within 1-2 minutes and affect all tenants. - name: segments-v3 - name: semantic-mapping-v3 description: >- Manage the global semantic name mappings table that maps raw OTel attribute keys to canonical semantic concepts. Changes propagate to the backing ClickHouse dictionary within 1-2 minutes and affect all tenants. - name: server-info-v3 description: Endpoints related to retrieving server information - name: sessions-v3 description: v3 session APIs - name: team-roles-v3 - name: team-v3 - name: traces-v3 description: v3 trace api for monitoring - name: fetch-sessions-v3 description: v3 fetch sessions api for monitoring - name: user-access-key description: > CRUD operations for user API keys. All endpoints are user-scoped — each user can only operate on their own API keys. No one including Org admins have access to other users' API keys. - name: users-v3 - name: version-compatibility-v3 - name: webhooks externalDocs: url: https://docs.fiddler.ai description: Find out more about Fiddler paths: /v3/evals/experiments/{experiment_id}/metrics: get: tags: - experiment-v3 summary: Get Experiment Metrics description: >- Get per-evaluator aggregate metrics for an experiment. Auto-detects each evaluator's chart type based on score cardinality: numeric_range (>10 distinct numeric values, histogram), numeric_categorical (<=10 distinct numeric values, distribution bars), or categorical (label-only scores, distribution with ratios). operationId: getExperimentMetrics parameters: - $ref: '#/components/parameters/experiment_id' responses: '200': description: Aggregate metrics per evaluator for the experiment content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiResponse' - type: object properties: data: $ref: '#/components/schemas/ExperimentMetricsResponse' '400': $ref: '#/components/responses/400' '401': $ref: '#/components/responses/401' '403': $ref: '#/components/responses/403' '404': $ref: '#/components/responses/404' '500': $ref: '#/components/responses/500' components: parameters: experiment_id: name: experiment_id in: path description: Path parameter for unique identifier of an experiment required: true schema: type: string format: uuid schemas: ApiResponse: type: object description: | Response object for standard API responses. properties: api_version: type: string default: '3.0' enum: - '2.0' - '3.0' description: | API version. kind: type: string default: NORMAL enum: - NORMAL description: | Type of response, indicating a normal response. ExperimentMetricsResponse: type: object title: Experiment Metrics Response description: Aggregate metrics for all evaluators in an experiment. required: - total_evaluators - total_scores - total_items - evaluators properties: total_evaluators: type: integer minimum: 0 description: > Number of distinct evaluator names in this experiment. For multi-score evaluators, this counts the evaluator once regardless of how many sub-scores it produces. example: 3 total_scores: type: integer minimum: 0 description: > Total number of (evaluator_name, score_name) entries in the evaluators array. For single-score evaluators this equals total_evaluators. For multi-score evaluators this is higher. example: 5 total_items: type: integer minimum: 0 description: > Total number of scored experiment items (taken as the maximum item count across all evaluators). example: 50 evaluators: type: array description: > Ordered list of per-evaluator metrics. Empty when no scores have been recorded yet. items: $ref: '#/components/schemas/EvaluatorMetric' EvaluatorMetric: title: Evaluator Metric description: > Per-evaluator aggregate metrics. The shape of the object is determined by the `type` discriminator field: - `numeric_range` → `NumericRangeEvaluatorMetric` (contains `histogram`) - `numeric_categorical` → `CategoricalEvaluatorMetric` (contains `distribution`) - `categorical` → `CategoricalEvaluatorMetric` (contains `distribution`) oneOf: - $ref: '#/components/schemas/NumericRangeEvaluatorMetric' - $ref: '#/components/schemas/CategoricalEvaluatorMetric' ErrorResponse: type: object description: | Response object for errors returned by the API. properties: api_version: type: string default: '3.0' enum: - '2.0' - '3.0' description: | API version of the response. kind: type: string default: ERROR enum: - ERROR description: | Type of response, usually indicating an error. error: type: object properties: code: type: integer format: int32 description: > Represents the code for this error, typically an HTTP response code. default: 400 enum: - 400 - 403 - 404 - 500 message: type: string description: > A human-readable message providing more details about the error. If there are multiple errors, it will be the message for the first error. example: Resource Not Found errors: type: array description: > Container for additional information regarding the error, especially for multiple errors. items: type: object properties: reason: type: string description: > Unique identifier for this error, different from the error code. example: ResourceNotFoundException message: type: string description: > A human-readable message providing more details about the error. If there is only one error, this field will match error.message. example: Resource Not Found help: type: string description: > Link to support or documentation providing more information on the error. NumericRangeEvaluatorMetric: title: Numeric Range Evaluator Metric description: > Evaluator metric for continuous numeric scores (>10 distinct values). Includes an equal-width histogram with up to 10 bins. allOf: - $ref: '#/components/schemas/EvaluatorMetricBase' - type: object properties: type: type: string enum: - numeric_range histogram: type: array maxItems: 10 description: > Equal-width histogram bins covering the full score range. Always has at most 10 bins. Bins are ordered by ascending `low` edge. items: $ref: '#/components/schemas/HistogramBin' required: - type - histogram CategoricalEvaluatorMetric: title: Categorical Evaluator Metric description: > Evaluator metric for categorical or discrete-numeric scores. Includes a value distribution ordered by descending count. allOf: - $ref: '#/components/schemas/EvaluatorMetricBase' - type: object properties: type: type: string enum: - numeric_categorical - categorical distribution: type: array description: | Per-value bucket counts and ratios, ordered by descending count. items: $ref: '#/components/schemas/DistributionBucket' required: - type - distribution EvaluatorMetricBase: type: object title: Evaluator Metric Base description: Fields common to all evaluator metric types. required: - evaluator_name - score_name - type - count - error_count - mean properties: evaluator_name: type: string description: Name of the evaluator. example: coherence score_name: type: string description: > Name of the specific score within the evaluator. For single-score evaluators this equals evaluator_name. For multi-score evaluators like ftl_prompt_safety, each sub-score (e.g. jailbreak_prob, illegal_prob) gets its own entry. example: coherence type: type: string description: > Auto-detected type of the evaluator output. `numeric_range` — continuous numeric scores with >10 distinct values (rendered as histogram). `numeric_categorical` — discrete numeric scores with <=10 distinct values (rendered as distribution bars). `categorical` — string label scores (rendered as distribution bars). enum: - numeric_range - numeric_categorical - categorical count: type: integer minimum: 0 description: Total number of scored items for this evaluator. example: 50 error_count: type: integer minimum: 0 description: Number of items where the evaluator returned a non-SUCCESS status. example: 2 mean: type: number format: double nullable: true description: > Mean numeric score across all items. Null for purely categorical evaluators that have no numeric score value. example: 0.762 HistogramBin: type: object title: Histogram Bin description: > A single equal-width bin in a numeric-range evaluator histogram. `low` and `high` are the inclusive lower and exclusive upper bin edges. `mean` and `stddev` are computed over the scores that fall in this bin. required: - low - high - count - mean - stddev properties: low: type: number format: double description: Lower edge of the bin (inclusive). example: 0 high: type: number format: double description: Upper edge of the bin (exclusive, except for the last bin). example: 0.1 count: type: integer minimum: 0 description: Number of scores that fall within this bin. example: 12 mean: type: number format: double description: Mean score value for scores within this bin. example: 0.053 stddev: type: number format: double minimum: 0 description: Population standard deviation of scores within this bin. example: 0.028 DistributionBucket: type: object title: Distribution Bucket description: > A single bucket in a categorical or numeric-categorical evaluator distribution. `label` is the display string (the score value cast to string, or the score label). `ratio` is the fraction of total scored items that fall in this bucket. required: - label - count - ratio properties: label: type: string description: >- Display label for this bucket (stringified score value or score label). example: positive count: type: integer minimum: 0 description: Number of scores with this value/label. example: 34 ratio: type: number format: double minimum: 0 maximum: 1 description: Fraction of total scored items represented by this bucket. example: 0.68 responses: '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Resource not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: BearerAuth: type: http scheme: bearer ````