Braintrust Experiments API

openapi: 3.0.3
info:
  title: Braintrust REST ACL Experiments API
  description: The Braintrust REST API for building, evaluating, and observing AI applications. The API is organized around REST, uses predictable resource-oriented URLs under https://api.braintrust.dev/v1, accepts and returns JSON, and authenticates with a Bearer API key. This specification covers the core documented resource surface - projects, experiments, datasets, logs/spans, prompts, functions and scorers, evals, project configuration, organization/ACL management, credentials, and the OpenAI-compatible AI proxy.
  termsOfService: https://www.braintrust.dev/legal/terms-of-service
  contact:
    name: Braintrust Support
    email: support@braintrust.dev
    url: https://www.braintrust.dev/docs
  version: '1.0'
servers:
- url: https://api.braintrust.dev
  description: US data plane (default)
- url: https://api-eu.braintrust.dev
  description: EU data plane
security:
- bearerAuth: []
tags:
- name: Experiments
paths:
  /v1/experiment:
    get:
      operationId: getExperiment
      tags:
      - Experiments
      summary: List experiments
      description: List out all experiments, optionally filtered and paginated.
      parameters:
      - $ref: '#/components/parameters/Limit'
      - $ref: '#/components/parameters/StartingAfter'
      - $ref: '#/components/parameters/EndingBefore'
      - name: project_id
        in: query
        schema:
          type: string
          format: uuid
        description: Filter experiments to a project.
      - name: experiment_name
        in: query
        schema:
          type: string
        description: Filter to an experiment with the given name.
      responses:
        '200':
          description: Returns a list of experiments.
          content:
            application/json:
              schema:
                type: object
                properties:
                  objects:
                    type: array
                    items:
                      $ref: '#/components/schemas/Experiment'
        '401':
          $ref: '#/components/responses/Unauthorized'
    post:
      operationId: postExperiment
      tags:
      - Experiments
      summary: Create experiment
      description: Create a new experiment. If there is an existing experiment with the same name as the one specified in the request, will return the existing experiment unmodified.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateExperiment'
      responses:
        '200':
          description: Returns the new experiment object.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Experiment'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v1/experiment/{experiment_id}:
    parameters:
    - $ref: '#/components/parameters/ExperimentId'
    get:
      operationId: getExperimentId
      tags:
      - Experiments
      summary: Get experiment
      responses:
        '200':
          description: Returns the experiment object.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Experiment'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    patch:
      operationId: patchExperimentId
      tags:
      - Experiments
      summary: Partially update experiment
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                name:
                  type: string
                description:
                  type: string
                metadata:
                  type: object
                  additionalProperties: true
      responses:
        '200':
          description: Returns the updated experiment object.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Experiment'
        '401':
          $ref: '#/components/responses/Unauthorized'
    delete:
      operationId: deleteExperimentId
      tags:
      - Experiments
      summary: Delete experiment
      responses:
        '200':
          description: Returns the deleted experiment object.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Experiment'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v1/experiment/{experiment_id}/insert:
    parameters:
    - $ref: '#/components/parameters/ExperimentId'
    post:
      operationId: postExperimentIdInsert
      tags:
      - Experiments
      summary: Insert experiment events
      description: Insert a set of events into the experiment. Events are upserted by id; equivalent to the SDK's logging interface.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - events
              properties:
                events:
                  type: array
                  description: A list of experiment events to insert.
                  items:
                    $ref: '#/components/schemas/InsertEvent'
      responses:
        '200':
          description: Returns the row ids of the inserted events.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/InsertEventsResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v1/experiment/{experiment_id}/fetch:
    parameters:
    - $ref: '#/components/parameters/ExperimentId'
    post:
      operationId: postExperimentIdFetch
      tags:
      - Experiments
      summary: Fetch experiment (POST form)
      description: Fetch the events in an experiment. Use the POST form to express complex filters, limits, and cursors in the request body.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/FetchEventsRequest'
      responses:
        '200':
          description: Returns the fetched events.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FetchEventsResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
    get:
      operationId: getExperimentIdFetch
      tags:
      - Experiments
      summary: Fetch experiment (GET form)
      parameters:
      - $ref: '#/components/parameters/Limit'
      - name: max_xact_id
        in: query
        schema:
          type: string
      - name: max_root_span_id
        in: query
        schema:
          type: string
      responses:
        '200':
          description: Returns the fetched events.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FetchEventsResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v1/experiment/{experiment_id}/feedback:
    parameters:
    - $ref: '#/components/parameters/ExperimentId'
    post:
      operationId: postExperimentIdFeedback
      tags:
      - Experiments
      summary: Feedback for experiment events
      description: Log feedback for a set of experiment events.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - feedback
              properties:
                feedback:
                  type: array
                  items:
                    $ref: '#/components/schemas/FeedbackItem'
      responses:
        '200':
          $ref: '#/components/responses/Empty'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v1/experiment/{experiment_id}/summarize:
    parameters:
    - $ref: '#/components/parameters/ExperimentId'
    get:
      operationId: getExperimentIdSummarize
      tags:
      - Experiments
      summary: Summarize experiment
      description: Summarize the scores and metrics of an experiment.
      parameters:
      - name: summarize_scores
        in: query
        schema:
          type: boolean
      - name: comparison_experiment_id
        in: query
        schema:
          type: string
          format: uuid
      responses:
        '200':
          description: Returns the experiment summary.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SummarizeExperimentResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    InsertEvent:
      type: object
      description: A single event (trace span, experiment row, or dataset record). Events are merged/upserted by id.
      properties:
        id:
          type: string
          description: A unique identifier for the event. If omitted, one is generated.
        input:
          description: The arguments that uniquely define a test case or trace input.
        output:
          description: The output of your application for the given input.
        expected:
          description: The ground-truth value to compare against.
        scores:
          type: object
          additionalProperties:
            type: number
            nullable: true
          description: A map of score names to score values between 0 and 1.
        metadata:
          type: object
          additionalProperties: true
        tags:
          type: array
          items:
            type: string
        metrics:
          type: object
          additionalProperties: true
        span_attributes:
          type: object
          additionalProperties: true
        _is_merge:
          type: boolean
          description: If true, this event is merged into an existing event with the same id.
    Experiment:
      type: object
      properties:
        id:
          type: string
          format: uuid
        project_id:
          type: string
          format: uuid
        name:
          type: string
        description:
          type: string
          nullable: true
        created:
          type: string
          format: date-time
          nullable: true
        repo_info:
          type: object
          nullable: true
          additionalProperties: true
        base_exp_id:
          type: string
          format: uuid
          nullable: true
        dataset_id:
          type: string
          format: uuid
          nullable: true
        public:
          type: boolean
        metadata:
          type: object
          nullable: true
          additionalProperties: true
    FeedbackItem:
      type: object
      required:
      - id
      properties:
        id:
          type: string
          description: The id of the event to provide feedback for.
        scores:
          type: object
          additionalProperties:
            type: number
            nullable: true
        expected:
          description: The ground truth value the event should have produced.
        comment:
          type: string
        metadata:
          type: object
          additionalProperties: true
        source:
          type: string
          enum:
          - app
          - api
          - external
    FetchEventsResponse:
      type: object
      properties:
        events:
          type: array
          items:
            type: object
            additionalProperties: true
        cursor:
          type: string
          nullable: true
          description: A pagination cursor to pass to fetch the next page of events.
    Error:
      type: object
      properties:
        error:
          type: string
          description: A human-readable error message.
    FetchEventsRequest:
      type: object
      properties:
        limit:
          type: integer
          description: Maximum number of events to return.
        max_xact_id:
          type: string
          description: Pagination cursor - the maximum transaction id from a previous page.
        max_root_span_id:
          type: string
          description: Pagination cursor - the maximum root span id from a previous page.
        version:
          type: string
        filters:
          type: array
          description: A list of filters to apply, using path-lookup style.
          items:
            type: object
            additionalProperties: true
    SummarizeExperimentResponse:
      type: object
      properties:
        project_name:
          type: string
        experiment_name:
          type: string
        project_url:
          type: string
        experiment_url:
          type: string
        comparison_experiment_name:
          type: string
          nullable: true
        scores:
          type: object
          nullable: true
          additionalProperties:
            type: object
            properties:
              name:
                type: string
              score:
                type: number
              diff:
                type: number
                nullable: true
              improvements:
                type: integer
              regressions:
                type: integer
        metrics:
          type: object
          nullable: true
          additionalProperties: true
    InsertEventsResponse:
      type: object
      properties:
        row_ids:
          type: array
          description: The ids of all rows that were inserted, aligning with the input order.
          items:
            type: string
    CreateExperiment:
      type: object
      required:
      - project_id
      properties:
        project_id:
          type: string
          format: uuid
        name:
          type: string
        description:
          type: string
        base_exp_id:
          type: string
          format: uuid
        dataset_id:
          type: string
          format: uuid
        dataset_version:
          type: string
        public:
          type: boolean
        metadata:
          type: object
          additionalProperties: true
        repo_info:
          type: object
          additionalProperties: true
  parameters:
    EndingBefore:
      name: ending_before
      in: query
      description: Pagination cursor id. Together with limit, returns the previous page before the object with this id.
      schema:
        type: string
        format: uuid
    Limit:
      name: limit
      in: query
      description: Limit the number of objects to return.
      schema:
        type: integer
        minimum: 0
    ExperimentId:
      name: experiment_id
      in: path
      required: true
      description: Experiment id, the unique identifier of the experiment.
      schema:
        type: string
        format: uuid
    StartingAfter:
      name: starting_after
      in: query
      description: Pagination cursor id. Together with limit, returns the next page after the object with this id.
      schema:
        type: string
        format: uuid
  responses:
    Empty:
      description: Success.
      content:
        application/json:
          schema:
            type: object
    Unauthorized:
      description: Authentication failed - missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: The requested resource was not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: API key or JWT
      description: 'Authenticate requests with your Braintrust API key in the Authorization header, e.g. `Authorization: Bearer $BRAINTRUST_API_KEY`.'