---
title: Overview
seoTitle: "Open Source LLM API & Data Platform"
description: Langfuse is designed to be extensible and flexible. People using Langfuse are building all kinds of workflows and customizations on top of it. This is powered by our open data platform.
---

# API & Data Platform

**Langfuse is designed to be open, extensible and flexible** (see [_why Langfuse?_](/why)). People using Langfuse are building all kinds of workflows and customizations on top of it. This is powered by our open data platform.

Example use cases:

- Billing based on LLM costs tracked in Langfuse
- Reporting of online evaluations in external dashboards
- Fine-tuning based on raw exports of traces
- Correlation of LLM Evals with observed user behavior in Data Warehouse

## Start here

```mermaid
graph LR
    LF["Langfuse<br/><br/>• Traces<br/>• Prompts<br/>• Scores<br/>•Experiments<br/>•Evaluators"]

    LF --> API["Public API"]
    LF --> Dash["In-app Dashboards"]
    LF --> Metrics["Metrics API v2"]
    LF --> Observations["Observations API v2"]
    LF --> Export["Exports to S3 / DWH"]
```

Choose the data access path based on what you want to build:

| Goal                                                           | Recommended path                                                                   |
| -------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| Work with Langfuse from a terminal or coding agent             | [CLI](/docs/api-and-data-platform/features/cli)                                    |
| Connect an AI tool that cannot run shell commands              | [MCP Server](/docs/api-and-data-platform/features/mcp-server)                      |
| Query aggregate cost, usage, latency, volume, or score metrics | [Metrics API v2](/docs/metrics/features/metrics-api#v2)                            |
| Retrieve experiment runs, items, and evaluation scores         | [Experiments API](/docs/api-and-data-platform/features/experiments-api)            |
| Retrieve row-level spans, generations, or events               | [Observations API v2](/docs/api-and-data-platform/features/observations-api#v2)    |
| Use the API from Python or JS/TS                               | [Query via SDKs](/docs/api-and-data-platform/features/query-via-sdk)               |
| Export large volumes on a schedule                             | [Blob Storage Export](/docs/api-and-data-platform/features/export-to-blob-storage) |
| Download a filtered one-off export                             | [Export from UI](/docs/api-and-data-platform/features/export-from-ui)              |
| Manage prompts, datasets, projects, and other resources        | [Public API](/docs/api-and-data-platform/features/public-api)                      |

## Features

- [Langfuse for Agents](/agents)
- [CLI](/docs/api-and-data-platform/features/cli)
- [MCP Server](/docs/api-and-data-platform/features/mcp-server)
- [Public API](/docs/api-and-data-platform/features/public-api)
- [Query via SDKs](/docs/api-and-data-platform/features/query-via-sdk)
- [Observations API](/docs/api-and-data-platform/features/observations-api)
- [Experiments API](/docs/api-and-data-platform/features/experiments-api)
- [Metrics API](/docs/metrics/features/metrics-api)
- [Export from UI](/docs/api-and-data-platform/features/export-from-ui)
- [Export to Blob Storage](/docs/api-and-data-platform/features/export-to-blob-storage)
- [Export to PostHog](/integrations/analytics/posthog)
- [Export to Mixpanel](/integrations/analytics/mixpanel)

<!-- agent-instructions -->

---

## Agent Instructions

This page is part of the [Langfuse](https://langfuse.com) documentation, published as plain Markdown for AI agents. Every page is available as Markdown by appending `.md` to its URL, or by sending an `Accept: text/markdown` header. This page: `https://langfuse.com/docs/api-and-data-platform/overview.md`.

### Querying these docs

If the answer is not on this page, query the documentation instead of guessing:

- **Semantic search** across all Langfuse docs, returning an answer with the relevant pages and excerpts. Ask a specific, self-contained question:

  ```bash
  curl -sG "https://langfuse.com/api/search-docs" --data-urlencode "query=How do I trace a LangGraph agent?"
  ```

- **Index of every page**: <https://langfuse.com/llms.txt>, with per-section indexes [llms-docs.txt](https://langfuse.com/llms-docs.txt), [llms-integrations.txt](https://langfuse.com/llms-integrations.txt), and [llms-self-hosting.txt](https://langfuse.com/llms-self-hosting.txt).

### Before writing Langfuse code

- **Install the [Langfuse Agent Skill](https://langfuse.com/docs/api-and-data-platform/features/agent-skill).** It encodes Langfuse's own best practices for instrumentation, prompt management, and evaluation, and materially improves results.
- **Read [What does a good trace look like?](https://langfuse.com/docs/observability/best-practices.md)** before instrumenting an application.
- **Verify endpoints, parameters, and response fields** against the [API reference](https://api.reference.langfuse.com) instead of inferring them from code examples.
- **Use the [Langfuse CLI](https://langfuse.com/docs/api-and-data-platform/features/cli)** (`npx langfuse-cli api <resource> <action>`) to read or write traces, prompts, datasets, and scores from the terminal.

Found an error in these docs? Please open an issue at <https://github.com/langfuse/langfuse-docs/issues>.