Langfuse · LLM observability platform

Langfuse

Open-source tracing, prompt management and evaluation for LLM applications, self-hosted or in the cloud.

Provider: Langfuse
Latest confirmed model: Not applicable / not verified
Pricing: Open source
Free plan: Yes
API: Yes · free quota
Status: Generally available
Last verified: Oct 19, 2026

Visit official website Pricing page API docs

What is Langfuse?

Langfuse records what your LLM app does, including model calls, retrieval steps and agent actions, so you can debug, measure cost and quality, and improve prompts. It also offers prompt versioning, datasets, evaluations and a playground. The core is MIT-licensed and free to self-host; Langfuse Cloud is a hosted version with usage-based plans.

Understanding and improving LLM app behaviour, cost and quality in production.

Why use Langfuse?

Practical benefits

MIT-licensed core, free self-hosting
Free cloud Hobby plan without a credit card
Integrations with LangChain, LlamaIndex, OpenAI, CrewAI and more
Typed Python and JS/TS SDKs

Who it suits

Teams running LLM apps in production
Developers evaluating prompts
Companies needing self-hosted observability

When another tool may fit better

Single-user experiments with no need for tracing
Teams wanting all enterprise features free when self-hosting (ee folders are excluded from MIT)

Learning curve: Some experience helps
Skills needed: Programming; DevOps for self-hosting.

Example workflows

Add the Langfuse SDK, trace each request, review traces and scores in the dashboard

What can it do?

Tracing and observabilityTraces LLM calls, retrieval and agent actions.
Prompt managementVersioned prompts.
EvaluationsLLM-as-a-judge, code evaluators, user feedback and manual labelling.
Datasets and playgroundTest sets and prompt iteration.
Self-hostingDocker Compose, Kubernetes (Helm) and Terraform templates for AWS, Azure, GCP.
Data retention management Depends on planAvailable on Pro and Enterprise cloud plans.

Good for

Debugging agents
Tracking LLM cost and latency
Prompt A/B testing
Quality evaluation

Where it runs

Web (cloud)DockerKubernetesPython SDKJS/TS SDK

Pricing and plans

Open source Self-hosting the open-source core is free. Langfuse Cloud: Hobby free (50k units/month), Core $29/month, Pro $199/month and Enterprise $2,499/month, each with 100k units included and graduated overage from $8 per 100k units.

Plan	Price	Billing	Free trial / tier	Usage limits	Main inclusions	Model access	API access	Restrictions
Self-hosted (open source)	Free	per month	Free tier	Your infrastructure	Core platform	—	Yes	Enterprise features need a licence
Hobby	Free	per month	Free tier	50k units/month; 30-day data access; 2 users	Tracing Prompts Evals	—	Yes	No overage
Core	$29/mo	per month	—	100k units included; $8 per 100k overage (lower at volume); 90-day data access	Unlimited users	—	Yes	—
Pro	$199/mo Teams add-on $300/month	per month	—	100k units included; 3-year data access	Data retention management Unlimited users	—	Yes	—
Enterprise	$2,499/mo Custom yearly pricing also available	per month	—	100k units included; 3-year data access	Data retention management Unlimited users	—	Yes	—

Prices in USD · Global list price · Taxes may apply · Verified Oct 19, 2026

Official pricing page (opens in a new tab)

API and developer access

Official API: Yes
Documentation: API docs (opens in a new tab)
Authentication: API keys (public/secret)
Pricing model: per 100k units
Free API quota: Hobby: 50k units per month
Rate limits: Not documented
Context / input limits: Not documented
SDKs: Python, JavaScript/TypeScript
Streaming: Not documented
Batch processing: Not documented
Structured output: Not documented
Tool / function calling: Not documented
Commercial use: MIT except ee folders
Data retention & privacy: Data access 30 days (Hobby), 90 days (Core), 3 years (Pro/Enterprise)

Published API rates

Item	Price	Unit
Overage 100k-1M units	$8	per 100k units
Overage 1M-10M units	$7	per 100k units
Overage above 50M units	$6	per 100k units

A free Langfuse account is not the same thing as free API access. The API allowance above is the provider's documented developer quota.

Verified Oct 19, 2026

Advantages and disadvantages

Advantages

Open source with full self-hosting
Broad integrations
Transparent usage pricing

Disadvantages

Enterprise (ee) features are outside the MIT licence
Hobby plan limited to 2 users and 30-day data access
Self-hosting requires infrastructure work

Privacy: Self-hosting keeps all trace data on your infrastructure.

Real-world examples

A solo developer tracing a chatbot

Sign up for the free Hobby plan (no card)
Add the SDK to the app
Inspect up to 50k units per month

free plan works

A company self-hosting for privacy

Deploy with the Helm chart on Kubernetes
Point the SDK at your instance
Keep all traces in-house

free plan works

A team evaluating prompt changes

Create a dataset of test inputs
Run two prompt versions
Score with LLM-as-a-judge and compare

free plan works

Langfuse alternatives

LangChain

Open-source framework for building LLM apps and agents that work with many model providers.

has a free plan · offers an API · open source / open-weight

Langfuse vs LangChain

LlamaIndex

Open-source framework for connecting LLMs to your data, plus the commercial LlamaParse document platform.

has a free plan · offers an API · open source / open-weight

Langfuse vs LlamaIndex

CrewAI

Open-source Python framework for teams of role-based AI agents, with a hosted platform for building and running them.

has a free plan · offers an API · open source / open-weight

Langfuse vs CrewAI

Compare Langfuse with these side by side

Frequently asked questions

Is Langfuse free?

Yes. The open-source core can be self-hosted for free, and Langfuse Cloud has a free Hobby plan with 50k units per month and no credit card.

What licence does Langfuse use?

MIT, except for code in the ee folders, which is excluded from the MIT licence.

How much does Langfuse Cloud cost?

Core is $29/month, Pro $199/month and Enterprise $2,499/month, each including 100k units, with overage starting at $8 per 100k units.

How do I self-host Langfuse?

Use Docker Compose locally or on a VM, Helm on Kubernetes for production, or Terraform templates for AWS, Azure and GCP.

Does Langfuse work with LangChain and LlamaIndex?

Yes, both are listed among its core integrations, along with OpenAI, LiteLLM, Vercel AI SDK and others.

How long is data kept?

Cloud data access is 30 days on Hobby, 90 days on Core and 3 years on Pro and Enterprise.