8 best Langfuse alternatives for startups: self-hosted, cheaper and open source (2026)

This post compares eight alternatives to Langfuse on self-hosting effort, license, price and the features that need an enterprise plan. For each Langfuse alternative, it lists what the tool adds and what it lacks.

The short answer

• Self-hosted without ClickHouse: AcruxCore runs on Postgres and Redis. MLflow and Arize Phoenix each run as one Python process on SQLite.
• Cheapest paid cloud: Opik, at $19 a month.
• A gateway, prompts, traces and evals in one open-source tool: AcruxCore or MLflow.
• Built for LangChain apps: LangSmith.

Langfuse alternatives: feature comparison

License, hosting and price

Tool	License	Data stores to self-host	Hosted free plan	Cheapest paid plan	Data kept on the paid plan
Langfuse	MIT core; enterprise (ee/) folders commercial	4: Postgres, ClickHouse, Redis, S3	Hobby: 50,000 units, 2 users, 30 days	Core: $29 a month, unlimited users	90 days
AcruxCore	Apache-2.0	2: Postgres, Redis	Free; span content kept 90 days	None; the hosted plan is free	Not applicable
MLflow	Apache-2.0	1: SQLite (Postgres and S3 for production)	None outside Databricks	Through Databricks	You decide
OpenLIT	Apache-2.0; Enterprise Edition commercial	2: ClickHouse, SQLite	No hosted plan yet	No public price	You decide
Laminar	Apache-2.0	3: Postgres, ClickHouse, Quickwit	1 GB, 1 seat, 7 days	Starter: $30 a month, unlimited seats	30 days
Opik	Apache-2.0	5: MySQL, Redis, ClickHouse, ZooKeeper, MinIO	25,000 spans a month, 10 members, 60 days	Pro: $19 a month, 50 members	60 days
Arize Phoenix	Elastic License 2.0	1: SQLite or Postgres	Arize AX Free: 25,000 spans, 15 days	Arize AX Pro: $50 a month	30 days
LangSmith	Closed source	Enterprise plan only	Developer: 5,000 traces, 1 seat, 14 days	Plus: $39 per seat a month	14 days
Braintrust	Closed source	Enterprise plan only	1 GB, unlimited users, 14 days	Pro: $249 a month	30 days

Features

Tool	Prompt versions	Gateway (your model calls pass through it)	Evals on datasets	Evals on live traffic	Status in 2026
Langfuse	Yes	No	Yes	Yes	Active; owned by ClickHouse since January 2026
AcruxCore	Yes	Yes	Yes	Yes	Active; public since August 2026
MLflow	Yes	Yes	Yes	Yes	Active; a Linux Foundation project
OpenLIT	Yes	No	Not in the docs we read	Yes	Active; hosted plan announced, not launched
Laminar	No	No	Yes	Signals (rules in plain English)	Active
Opik	Yes	Beta, for development and testing	Yes	Yes	Active
Arize Phoenix	Yes	No	Yes	Yes	Active
LangSmith	Yes	Beta	Yes	Yes	Active
Braintrust	Yes	Yes, hosted, in public preview	Yes	Yes	Active

A unit on Langfuse is one trace, one step inside a trace, or one score. A span is one step inside a trace. "Data stores" counts databases, caches, queues and file stores, not the application containers. Closed source means the vendor publishes no server code.

Why look for alternatives to Langfuse?

• Self-hosting runs four data stores. A Langfuse install runs Postgres, ClickHouse, Redis and S3-compatible storage, plus a web and a worker container.
• Some features need an enterprise license, even self-hosted. Audit logs, project-level roles, data retention controls, automatic user provisioning (SCIM), protected prompt labels and server-side masking are in the enterprise (ee/) folders.
• Langfuse has no gateway. Langfuse records model calls but does not send them to the provider. The Langfuse docs use LiteLLM as the gateway in front of it.
• Every step is billed. Each step and each score inside a trace counts as one unit. The Hobby plan stops at 50,000 units with no overage, and Core charges $8 per 100,000 units over the included 100,000.
• ClickHouse owns Langfuse. ClickHouse acquired Langfuse in January 2026. The Langfuse core stays MIT, and Langfuse Cloud stays a product separate from ClickHouse Cloud.

Sources: Langfuse license, compose file, self-host pricing, cloud pricing, LiteLLM page, acquisition.

How we picked

• The tool does Langfuse's core jobs: tracing, and at least one of prompts or evals.
• The tool is active today. Each tool had a release or a commit in October 2026.
• The price is public, or the tool is free to self-host.
• Every fact comes from the vendor: the pricing page, the docs, the license file or the repository's compose file, read on 17 October 2026. We do not use other comparison lists as sources.

Self-hosted Langfuse alternatives

These five tools use a license approved by the Open Source Initiative, and each one is free to self-host.

1. AcruxCore

AcruxCore vs Langfuse: both are open source and cover prompts, tracing and evals. AcruxCore also has a gateway. A self-hosted AcruxCore needs only Postgres and Redis.

Best for: small teams that want prompts, a gateway, traces and evals in one self-hosted app.

	AcruxCore	Langfuse
License	Apache-2.0, no enterprise folder	MIT core; enterprise (ee/) folders commercial
Self-host	Postgres, Redis, API, worker, web	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	None; the hosted plan is free to use	Core: $29 a month, 100,000 units
Gateway	Yes	No

Where AcruxCore differs

• The gateway is part of the product. It holds your provider keys, caches responses, falls back to a second model, and stops calls at a spend budget or a rate limit.
• You define the tools a model can call and keep versions of them. AcruxCore runs a tool when your code calls its API.
• Roles and the audit log are free in every AcruxCore install. Langfuse keeps the audit log and project-level roles for its enterprise license.
• A prompt run can rewrite the prompt for you and score the new version against a dataset.

Limits of AcruxCore

• The AcruxCore repository went public in August 2026 and has 11 GitHub stars. Langfuse has 35,957 stars.
• AcruxCore has no SAML or OIDC single sign-on. Sign-in is email or Google.
• AcruxCore deletes span content after 90 days by default. One setting covers the whole install, not each project.
• The SDKs are Python and TypeScript only.

Our hands-on comparison is AcruxCore vs Langfuse.

Sources: license, compose file, pricing.

2. MLflow

MLflow vs Langfuse: MLflow is an Apache-2.0 ML platform with tracing, a prompt registry, judges and a gateway in one server.

Best for: teams that already run MLflow for classic machine learning.

	MLflow	Langfuse
License	Apache-2.0, Linux Foundation	MIT core; enterprise (ee/) folders commercial
Self-host	pip install mlflow and mlflow server on SQLite; Postgres and S3 storage for production	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	No public price; the managed version comes with Databricks	Core: $29 a month
Gateway	Yes	No

Where MLflow differs

• MLflow can run as one Python process with a SQLite file, with no Docker.
• The gateway splits traffic by weight, falls back to another model, and rejects calls over a USD budget.
• User permissions and workspaces are in the open-source version, with no license key.
• The same server holds your training runs and model registry.

Limits of MLflow

• MLflow has no hosted plan of its own. The managed version needs a Databricks workspace.
• Judges that score live traces need a gateway endpoint set up first.

Our comparison: AcruxCore vs MLflow.

Sources: license, GenAI docs, self-hosting, compose file, managed MLflow.

3. OpenLIT

OpenLIT vs Langfuse: OpenLIT is built on OpenTelemetry from the start and self-hosts on ClickHouse plus one app container.

Best for: teams that already run OpenTelemetry or Grafana and also want GPU metrics.

	OpenLIT	Langfuse
License	Apache-2.0; Enterprise Edition commercial	MIT core; enterprise (ee/) folders commercial
Self-host	ClickHouse and one app container	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	No hosted plan yet; Enterprise has no public price	Core: $29 a month
Gateway	No	No

Where OpenLIT differs

• The SDK sends standard OpenTelemetry data, so you can also export it to Grafana, Datadog or any OTLP backend.
• OpenLIT Vault stores your provider keys, and your code fetches the keys at run time.
• A separate collector reports GPU metrics for NVIDIA, AMD and Intel cards.
• The SDKs cover Python, TypeScript and Go.

Limits of OpenLIT

• Roles, audit logs and alerts need the Enterprise Edition.
• OpenLIT Cloud has a waitlist only, so today you must run OpenLIT yourself.

Sources: license, compose file, docs, pricing.

4. Laminar

Laminar vs Langfuse: Laminar is open-source tracing built for agents, with SQL over your traces and no prompt management.

Best for: teams that run agents with many steps, or agents that use a browser.

	Laminar	Langfuse
License	Apache-2.0; Signals and alerts need a license key when self-hosted	MIT core; enterprise (ee/) folders commercial
Self-host	Postgres, ClickHouse, Quickwit, frontend, app server	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	Starter: $30 a month, 3 GB, unlimited seats, 30 days	Core: $29 a month, 100,000 units, 90 days
Gateway	No	No

Where Laminar differs

• Laminar replays a browser agent's session as video, next to the matching steps of the trace.
• You can query traces, spans and metrics with SQL.
• Signals are rules written in plain English, such as "agent is stuck in a loop". Laminar checks every trace against these rules.
• Laminar bills by gigabyte of trace data, not by the number of steps.

Limits of Laminar

• Laminar has no prompt management, so you need another tool to version prompts.
• Laminar's free plan keeps data 7 days and allows 1 seat.

Our comparison: AcruxCore vs Laminar.

Sources: repository, compose file, pricing.

5. Opik

Opik vs Langfuse: the whole Opik platform is Apache-2.0, and Opik has the cheapest paid cloud plan here.

Best for: teams that want open-source evals and automatic prompt optimization.

	Opik	Langfuse
License	Apache-2.0	MIT core; enterprise (ee/) folders commercial
Self-host	MySQL, Redis, ClickHouse, ZooKeeper, MinIO, three app services	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	Pro: $19 a month, 100,000 spans, up to 50 members, 60 days	Core: $29 a month, 100,000 units, 90 days
Gateway	Beta, for development and testing	No

Where Opik differs

• Opik ships an optimizer package that rewrites prompts and agents for you, with six optimization algorithms.
• Opik has guardrails for PII, topics and prompt injection.
• Opik's free cloud plan keeps data 60 days for up to 10 members. Langfuse Hobby keeps 30 days for 2 users.

Limits of Opik

• The self-hosted version has no user management.
• A self-hosted install runs five data stores, one more than Langfuse.

Our comparison: AcruxCore vs Opik.

Sources: README and license, pricing, self-hosting, compose file, gateway, optimizer.

Source-available: Arize Phoenix

6. Arize Phoenix

Phoenix vs Langfuse: Phoenix self-hosts in one container with no feature limits. Its license, the Elastic License 2.0, is not approved by the Open Source Initiative.

Best for: engineers who want free self-hosted tracing and evals built on OpenTelemetry.

	Arize Phoenix	Langfuse
License	Elastic License 2.0	MIT core; enterprise (ee/) folders commercial
Self-host	One container, SQLite or Postgres	Postgres, ClickHouse, Redis, S3, web, worker
Cheapest paid plan	Arize AX Pro: $50 a month, 50,000 spans, unlimited users, 30 days	Core: $29 a month, 100,000 units, 90 days
Gateway	No	No

Where Phoenix differs

• Self-hosted Phoenix has no feature limits and no license fee.
• The Elastic License forbids selling Phoenix to others as a hosted service. Running Phoenix for your own team is allowed.
• Self-hosted Phoenix includes OAuth2, LDAP and role-based access.
• Tracing uses OpenInference, Arize's OpenTelemetry conventions.

Limits of Phoenix

• The hosted plans are small: 25,000 spans on Free and 50,000 on Pro.

Our comparison: AcruxCore vs Phoenix.

Sources: license, self-hosting, compose file, pricing.

Closed-source alternatives

LangSmith and Braintrust publish no server code. Self-hosting either one needs an enterprise contract.

7. LangSmith

LangSmith vs Langfuse: LangSmith is the LangChain team's hosted platform. Langfuse is open source and free to self-host.

Best for: apps built on LangChain or LangGraph.

	LangSmith	Langfuse
License	Closed source; SDKs MIT	MIT core; enterprise (ee/) folders commercial
Self-host	Enterprise plan only	Free
Cheapest paid plan	Plus: $39 per seat a month, 10,000 traces, 14 days	Core: $29 a month, unlimited users, 90 days
Gateway	Beta	No

Where LangSmith differs

• LangSmith has a gateway in beta, with spend and rate limits.
• LangSmith has SDKs for Go and Java as well as Python and TypeScript.
• Startups with venture funding can get up to $10,000 in credits.

Limits of LangSmith

• LangSmith keeps base traces 14 days. Keeping traces 180 days costs extra.
• Plus costs $39 per seat, so three people pay $117 a month before they pay for extra traces.

We compared both on one app in Langfuse vs LangSmith. For more options starting from LangSmith, see 8 LangSmith alternatives.

Sources: pricing, billing, gateway, self-hosting.

8. Braintrust

Braintrust vs Langfuse: Braintrust is a closed-source, hosted platform built around evals, with a flat price and unlimited users.

Best for: teams whose main work is evals and experiments.

	Braintrust	Langfuse
License	Closed source; SDKs Apache-2.0	MIT core; enterprise (ee/) folders commercial
Self-host	Enterprise only; your data stays in your cloud, Braintrust hosts the UI	Free
Cheapest paid plan	Pro: $249 a month, 5 GB, unlimited users, 30 days	Core: $29 a month, 90 days
Gateway	Yes, hosted, in public preview	No

Where Braintrust differs

• Loop is an agent inside Braintrust. It reads your logs and experiments, then edits prompts, scorers and datasets after you approve.
• The gateway caches responses for up to 7 days and falls back to another provider on errors.
• Braintrust gives Pro free for 6 to 12 months to startups that qualify.

Limits of Braintrust

• Braintrust's free plan keeps data 14 days.
• Self-hosting any part of Braintrust needs an Enterprise contract.

Our comparison: AcruxCore vs Braintrust.

Sources: pricing, self-hosting, gateway, Loop.

Tools other lists still recommend

Older lists of Langfuse alternatives still include these six tools. Their status on 17 October 2026:

• Lunary is no longer open source. Its server repository returns 404 on GitHub, and Docker self-hosting needs the Enterprise Edition. (source)
• Agenta now calls itself "the open-source workspace for your agents". Its current docs no longer cover prompts, evaluation or observability; those pages are in an archived v1.0 section. (source)
• Helicone was acquired by Mintlify in March 2026. The service runs in maintenance mode: it gets security fixes, bug fixes and new models, but no new features. (source)
• Portkey was acquired by Palo Alto Networks in May 2026. The open-source gateway repository has had no merged code since 25 May 2026. (source)
• Galileo was acquired by Cisco and is now sold as Splunk Agent Observability. (source)
• Traceloop announced in March 2026 that it is joining ServiceNow. Its OpenLLMetry library stays open source and active. (source)

We left out Pydantic Logfire: its platform is closed source, and self-hosting it needs an enterprise contract. (source)

Which Langfuse alternative should you pick?

Best Langfuse alternative for a startup

• AcruxCore if you want one self-hosted app for prompts, gateway, traces and evals, and the hosted plan is free to use.
• Opik if you want a paid cloud plan: $19 a month for up to 50 members.
• MLflow if you already use MLflow and want a gateway in the same server.

Cheaper alternatives to Langfuse

Tool	Cheapest paid plan	What it includes	Data kept
Langfuse	$29 a month	100,000 units, unlimited users	90 days
Opik	$19 a month	100,000 spans, up to 50 members	60 days
Laminar	$30 a month	3 GB, unlimited seats	30 days
Arize AX Pro	$50 a month	50,000 spans, unlimited users	30 days
LangSmith	$39 per seat a month	10,000 traces	14 days
Braintrust	$249 a month	5 GB, 50,000 scores, unlimited users	30 days
AcruxCore	Free	Every feature	90 days of span content

Best free Langfuse alternative

• AcruxCore, MLflow or Arize Phoenix to self-host without ClickHouse. AcruxCore runs on Postgres and Redis. MLflow and Phoenix each run as one Python process on SQLite. Phoenix's license forbids selling it as a hosted service.
• Opik for a free cloud plan that keeps data 60 days for up to 10 members.

For AI agent observability

• Laminar replays browser-agent sessions and checks every trace against plain-English rules.
• Opik and Phoenix trace OpenAI Agents SDK runs and score them with LLM judges.

If your app is built on LangChain

• LangSmith is built by the LangChain team. LangChain and LangGraph runs send traces to LangSmith once LANGSMITH_TRACING and LANGSMITH_API_KEY are set.

Langfuse alternatives for enterprises

• LangSmith Enterprise and Braintrust Enterprise include self-hosting, single sign-on and an uptime guarantee (SLA).
• Langfuse Enterprise costs $2,499 a month on the cloud. It adds audit logs, automatic user provisioning (SCIM) and an uptime SLA.

FAQ

Is Langfuse Apache 2.0?

No. The Langfuse core is under the MIT license. The ee/ folders are under a separate commercial license and need a Langfuse Enterprise agreement. (license)

Is Langfuse free?

The self-hosted core is free. The Hobby cloud plan is free for 50,000 units a month, 2 users and 30 days of data. (pricing)

What does self-hosting Langfuse take?

A web container, a worker container, Postgres, ClickHouse, Redis or Valkey, and S3-compatible storage. (self-hosting)

Who owns Langfuse now?

ClickHouse acquired Langfuse in January 2026. The core stays MIT-licensed. (announcement)

Does Langfuse have an LLM gateway?

No. Langfuse records model calls but does not send them to the provider. The Langfuse docs use LiteLLM as the gateway. AcruxCore and MLflow include a gateway. LangSmith and Opik have one in beta, and Braintrust has a hosted one in preview.

Related posts

• AcruxCore vs Langfuse: the same prompt built and run on both, with screenshots and a latency benchmark.
• Langfuse vs LangSmith: one app run end to end on both.
• 9 LLM observability tools tested hands-on: nine tools tested hands-on, with screenshots of each.
• AcruxCore vs Langfuse vs LangSmith: the same app run on all three.
• Langfuse hands-on walkthrough: every Langfuse screen, step by step.
• 8 LangSmith alternatives for startups: the same comparison, starting from LangSmith.
• Self-hosting AcruxCore: the docker compose setup.