Langfuse

license

MIT(core:tracing/integrations/API/data-model/exports/evals/playground/SSO)

commercial

enterprise-security(SCIM,audit-logs,data-retention)

source

public

core-gated

gated(the root LICENSE carves ee/, web/src/ee/ and worker/src/ee/ out of MIT and under ee/LICENSE, the Langfuse Enterprise License

An MIT core with a commercially licensed enterprise directory in the same repository. The gating is read directly from the repository and does not rest on Langfuse Cloud or on the ClickHouse acquisition. The root LICENSE splits the repo itself: "All content that resides under the 'ee/', 'web/src/ee/', and/or 'worker/src/ee/' directories of this repository, if these directories exist, is licensed under the license defined in 'ee/LICENSE'", and everything outside them is MIT Expat. ee/LICENSE opens by calling Langfuse "an open core project" and requires "a valid Langfuse Enterprise License". The carve-out is not a stub: ee/src holds a license-check module, and web/src/ee/features holds admin-api, audit-log-viewer, billing, multi-tenant-sso, sfdc-sync, sso-settings, ui-customization and verified-domains. That is genuine open core rather than fully open source. One correction the read forces: single sign-on is not in the MIT core, despite what the license detail recorded beside this note says - multi-tenant-sso and sso-settings both sit under web/src/ee/.

• https://langfuse.com/blog/2025-06-04-open-sourcing-langfuse-product recorded 2026-08-15

  Langfuse's own post on open-sourcing the remaining product surface under the MIT licence, while retaining a commercially licensed enterprise edition. Establishes both halves of the open_core reading.

• https://clickhouse.com/blog/clickhouse-acquires-langfuse-open-source-llm-observability recorded 2026-08-15

  ClickHouse's acquisition announcement, describing Langfuse as MIT-licensed open-source LLM observability. Context for ownership; the score explicitly does NOT rest on the acquisition, so this establishes no dimension.

• https://raw.githubusercontent.com/langfuse/langfuse/main/LICENSE recorded 2026-08-12

  Root LICENSE body, read rather than assumed. It opens "Portions of this software are licensed as follows:" and splits the repository: "All content that resides under the 'ee/', 'web/src/ee/', and/or 'worker/src/ee/' directories of this repository, if these directories exist, is licensed under the license defined in 'ee/LICENSE'", while "Content outside of the above mentioned directories or restrictions above is available under the 'MIT Expat' license", whose full text follows. So the tier-setting license is MIT and the gate is a carve-out named in the license itself.

• https://raw.githubusercontent.com/langfuse/langfuse/main/ee/LICENSE recorded 2026-08-12

  The Langfuse Enterprise License. Its preamble states "Langfuse is an open core project. Langfuse's core is permissively licensed (MIT license). Certain parts of the periphery of Langfuse are commercially licensed and governed by this Enterprise License." The grant itself: the software "may only be used, if you (and any entity that you represent) have agreed to, and are in compliance with, the applicable Langfuse Terms of Service ... or other agreement governing the use of the Software, as agreed by you and Langfuse, and otherwise have a valid Langfuse Enterprise License."

• https://api.github.com/repos/langfuse/langfuse/contents/web/src/ee/features recorded 2026-08-12

  What the carve-out actually withholds, listed rather than characterized: admin-api, audit-log-viewer, billing, multi-tenant-sso, sfdc-sync, sso-settings, ui-customization, verified-domains. These are features of the Langfuse product, not a separate hosted service beside it, which is the distinction the core_gated dimension turns on.

• https://api.github.com/repos/langfuse/langfuse/contents/ee/src recorded 2026-08-12

  The enforcement point. ee/src contains ee-license-check, env.ts and index.ts - a license check module in the enterprise-licensed half of the tree, which is the rubric's own wording for a gate.

• https://api.github.com/repos/langfuse/langfuse/contents/ recorded 2026-08-12

  Repository root. The published tree is the whole platform - web, worker, packages, fern, and docker-compose files for dev and prod - so self-hosting the MIT core needs nothing outside the repo and the source dimension is public. `ee` sits beside them as its own top-level directory.

The band rests on the PyPI package langfuse, the product's own client SDK: where a hosted platform has no other countable channel, its client SDK's downloads band the platform, the same way qdrant is banded on qdrant-client. pypistats answers 26,611,793 downloads in the last month for langfuse (6,315,194 in the last week, 1,118,108 in the last day), which clears the >10M floor for level 5. This is instrumentation traffic rather than a seat count, which is exactly what an observability platform's reach looks like. Langfuse is described as the most widely adopted open source LLM engineering platform, and was acquired by ClickHouse in March 2026.

• https://pypistats.org/api/packages/langfuse/recent recorded 2026-08-14

  last_month = 26,611,793 downloads for langfuse (last_week 6,315,194, last_day 1,118,108).

• https://github.com/langfuse/langfuse recorded 2026-08-15

  Repository page for langfuse/langfuse: 33.1k stars, 3.6k forks, MIT licence, public and unarchived. Corroboration only — the band is a measured PyPI count, not a star reading.

• https://clickhouse.com/blog/clickhouse-acquires-langfuse-open-source-llm-observability recorded 2026-08-15

  The acquisition announcement, read for a usage figure and containing none — no customer count, no trace volume, no user count.

End-to-end tracing, prompt management, evaluations including LLM-as-judge, datasets, annotation queues and a playground, with OpenTelemetry plus LangChain, OpenAI and LiteLLM integrations. There is no standard benchmark for observability, so the score is set on the feature matrix, and this 4 is the reference point the rest of this category is compared against.

• https://github.com/langfuse/langfuse recorded 2026-08-13

  Repository overview. The README still describes tracing, prompt management, evaluations, datasets and a playground as one platform, with OpenTelemetry and framework integrations.

• https://langfuse.com/docs/observability/overview recorded 2026-08-13

  Observability & Application Tracing. "The core of this is application tracing - structured logs of every request that capture the exact path", with Products in the sidebar listing Observability, Prompt Management, Evaluation and Playground.