Langfuse

About Langfuse

Financials

Dated, source-cited figures. Estimates are marked.

Products by Langfuse

All products by Langfuse reviewed by our AI panel of experts.

LangfuseLLM Platforms

Open-source LLM engineering platform for debugging, evaluating, and improving AI applications

From $29/mo8.0/10

How Our Review Panel Scores Langfuse

Six independent reviewer personalities assessed Langfuse's product on their own terms. They landed within 0.6 points of each other, an unusually strong consensus.

Averaged across 1 reviewed product in our catalog. Scores are out of 10.

Competitive Landscape

Who Langfuse competes with, and how they differ.

LangSmith8.1/10

LangChain's tracing, prompt-management, and eval platform overlaps almost feature-for-feature with Langfuse, but it is tightly coupled to the LangChain/LangGraph ecosystem while Langfuse is framework-agnostic and OSS-first.

2 products reviewed on TopReviewed

Helicone7.9/10

Closest OSS-first peer: a proxy-based (one-line integration) LLM observability tool versus Langfuse's SDK/OpenTelemetry-based tracing, with a smaller evaluation and prompt-management feature set.

1 product reviewed on TopReviewed

Arize AI (Phoenix)8.1/10

Open-source LLM tracing and evaluation rooted in Arize's traditional ML-monitoring product; its paid Arize AX tier targets larger enterprise observability budgets more aggressively than Langfuse's self-serve model.

1 product reviewed on TopReviewed

Braintrust8.0/10

Enterprise-focused LLM evaluation and observability platform with no self-hosted open-source option, relying on a higher-touch, sales-led go-to-market versus Langfuse's open-source, self-serve motion.

1 product reviewed on TopReviewed

Weights & Biases (Weave)8.0/10

Extends an established ML experiment-tracking platform into LLM tracing/eval via Weave, leaning on incumbent ML-team relationships rather than Langfuse's LLM-native, OSS-first design.

1 product reviewed on TopReviewed

Datadog LLM Observability7.0/10

Bundles LLM tracing and evaluation into its broader enterprise APM/observability suite, selling to existing Datadog customers on usage-based pricing rather than serving LLM-native or self-hosted developers directly.

1 product reviewed on TopReviewed

Company Timeline

Key milestones in Langfuse's history, with sources.

1. March 2026Launch

   Langfuse v4 — observations-centric ClickHouse data model

   Langfuse shifted to a single wide, mostly immutable ClickHouse table that eliminates joins and read-time deduplication, cutting dashboard load times by at least 10x after 19x growth in data processed over the prior year.

   langfuse.com
2. Jan 16, 2026Acquisition

   Acquired by ClickHouse

   ClickHouse acquired Langfuse (terms undisclosed) alongside the close of its $400M Series D; the Langfuse team joined ClickHouse while the product continues operating as open-source (MIT license) and self-hostable, with Langfuse Cloud unchanged.

   clickhouse.com
3. June 2025Milestone

   Open-sourced all product features under MIT license

   Langfuse moved LLM-as-a-Judge evaluations, annotation queues, prompt experiments, and the playground from its commercial tier to the open-source MIT license, leaving only enterprise security/platform features (SCIM, audit logs, data retention) commercial.

   langfuse.com
4. December 2024Milestone

   Shipped Langfuse v3 — migrated core infrastructure from Postgres to ClickHouse

   The largest infrastructure upgrade in company history at the time, moving Langfuse from a Postgres-backed prototype to a ClickHouse-backed platform able to ingest hundreds of millions of records.

   langfuse.com
5. April 2024Launch

   Launch Week 1 — rebranded as "The AI Engineering Platform"

   Langfuse introduced the LLM Playground, Datasets, and LLM-as-Judge evaluations, expanding beyond observability and prompt management; the launch was featured a second time as Product Hunt Product of the Day.

   langfuse.com
6. Nov 7, 2023Funding

   Seed round — $4M led by Lightspeed Venture Partners and La Famiglia

   Langfuse raised a $4M seed round led by Lightspeed Venture Partners and La Famiglia, with participation from Y Combinator and angel investors.

   langfuse.com
7. July 2023Launch

   Public launch as "Product Analytics for LLM Apps"

   Langfuse launched publicly via Show HN, Y Combinator's Launch YC, and Product Hunt, where it won Product of the Day and a Golden Kitty Award.

   langfuse.com
8. 2022Founded

   Langfuse founded in Berlin

   Marc Klingen, Max Deichmann, and Clemens Rawert began working together in Berlin in 2022, initially building a usage-based billing product (Finto) before pivoting to LLM application tooling.

   langfuse.com