Langfuse

Langfuse is an open-source LLM engineering platform offering tracing, evaluations, prompt management, datasets, and metrics. The Langfuse API supports both self-hosted and multi-region cloud deployments (US, EU, Japan, HIPAA-compliant US) and integrates with LangChain, LlamaIndex, OpenTelemetry, and any LLM stack.

9 APIs 0 Features

AILLMObservabilityOpen SourceEvaluations

APIs

Langfuse Tracing API

Ingest traces, observations (spans, generations, events), and scores into Langfuse. Recommended path is the OpenTelemetry endpoint; legacy ingestion API is also supported. Trace...

Langfuse Observations API

Read and query observations (spans, generations, events) attached to traces. Supports filtering by trace, time range, name, and metadata.

Langfuse Metrics API

Aggregated metrics across traces, observations, scores, and costs. Supports custom dimensions, time series, and project-scoped queries for dashboarding.

Langfuse Prompt Management API

Create, version, label, and retrieve prompts with client-side caching. Supports text and chat prompt types, configuration variables, and label-based deployment (e.g. production,...

Langfuse Datasets API

Manage datasets and dataset items (input/expected-output pairs) for offline evaluation runs and regression testing.

Langfuse Evaluations API

CRUD operations for evals: define evaluators (LLM-as-judge, code, human), trigger evaluations on traces or dataset runs, and read back scores and reasoning.

Langfuse Scores API

Attach numeric, categorical, or boolean scores to traces, observations, or sessions. Supports user feedback, model-graded scores, and custom-defined score schemas.

Langfuse Organizations & Projects API

Organization-level provisioning APIs to create projects, manage users, and configure project membership programmatically.

Langfuse Instance Management API

Instance-management endpoints for self-hosted Langfuse deployments. Used to administer organizations, license, and platform-wide configuration.

Resources

Sources

aid: langfuse
url: https://raw.githubusercontent.com/api-evangelist/langfuse/refs/heads/main/apis.yml
name: Langfuse
x-type: company
description: >-
  Langfuse is an open-source LLM engineering platform offering tracing, evaluations, prompt management, datasets, and metrics. The Langfuse API supports both self-hosted and multi-region cloud deployments (US, EU, Japan, HIPAA-compliant US) and integrates with LangChain, LlamaIndex, OpenTelemetry, and any LLM stack.
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
tags:
  - AI
  - LLM
  - Observability
  - Open Source
  - Evaluations
created: '2026-05-08'
modified: '2026-05-08'
specificationVersion: '0.19'
apis:
  - aid: langfuse:langfuse-tracing-api
    name: Langfuse Tracing API
    tags:
      - Tracing
      - OpenTelemetry
      - Ingestion
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/tracing
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/tracing
        type: Documentation
      - url: https://api.reference.langfuse.com/
        type: API Reference
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Ingest traces, observations (spans, generations, events), and scores into Langfuse. Recommended path is the OpenTelemetry endpoint; legacy ingestion API is also supported. Traces are the unit of usage billing.
  - aid: langfuse:langfuse-observations-api
    name: Langfuse Observations API
    tags:
      - Observations
      - Spans
      - Generations
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/api
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/api
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Read and query observations (spans, generations, events) attached to traces. Supports filtering by trace, time range, name, and metadata.
  - aid: langfuse:langfuse-metrics-api
    name: Langfuse Metrics API
    tags:
      - Metrics
      - Analytics
      - Reporting
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/analytics
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/analytics
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Aggregated metrics across traces, observations, scores, and costs. Supports custom dimensions, time series, and project-scoped queries for dashboarding.
  - aid: langfuse:langfuse-prompts-api
    name: Langfuse Prompt Management API
    tags:
      - Prompts
      - Versioning
      - Prompt Management
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/prompts
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/prompts
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Create, version, label, and retrieve prompts with client-side caching. Supports text and chat prompt types, configuration variables, and label-based deployment (e.g. production, staging).
  - aid: langfuse:langfuse-datasets-api
    name: Langfuse Datasets API
    tags:
      - Datasets
      - Test Data
      - Evaluations
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/datasets
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/datasets
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Manage datasets and dataset items (input/expected-output pairs) for offline evaluation runs and regression testing.
  - aid: langfuse:langfuse-evaluations-api
    name: Langfuse Evaluations API
    tags:
      - Evaluations
      - Scoring
      - LLM-as-Judge
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/evaluation
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/evaluation
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      CRUD operations for evals: define evaluators (LLM-as-judge, code, human), trigger evaluations on traces or dataset runs, and read back scores and reasoning.
  - aid: langfuse:langfuse-scores-api
    name: Langfuse Scores API
    tags:
      - Scores
      - Feedback
      - Quality
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/scores
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/scores
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Attach numeric, categorical, or boolean scores to traces, observations, or sessions. Supports user feedback, model-graded scores, and custom-defined score schemas.
  - aid: langfuse:langfuse-organizations-api
    name: Langfuse Organizations & Projects API
    tags:
      - Organizations
      - Projects
      - Provisioning
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/docs/api
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/docs/api
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Organization-level provisioning APIs to create projects, manage users, and configure project membership programmatically.
  - aid: langfuse:langfuse-instance-api
    name: Langfuse Instance Management API
    tags:
      - Self-Hosted
      - Administration
      - Instance
    image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://langfuse.com/self-hosting
    baseURL: https://cloud.langfuse.com/api/public
    properties:
      - url: https://langfuse.com/self-hosting
        type: Documentation
      - url: openapi/langfuse-openapi.yml
        type: OpenAPI
    description: >-
      Instance-management endpoints for self-hosted Langfuse deployments. Used to administer organizations, license, and platform-wide configuration.
common:
  - type: Website
    url: https://langfuse.com/
  - type: Documentation
    url: https://langfuse.com/docs
  - type: API Reference
    url: https://api.reference.langfuse.com/
  - type: Pricing
    url: https://langfuse.com/pricing
  - type: GitHub
    url: https://github.com/langfuse/langfuse
  - type: Plans
    url: plans/langfuse-plans-pricing.yml
  - type: RateLimits
    url: rate-limits/langfuse-rate-limits.yml
  - type: FinOps
    url: finops/langfuse-finops.yml
maintainers:
  - FN: Kin Lane
    email: [email protected]