Laminar vs Langfuse in 2026 - Which Open-Source Tracer Wins for Your Stack

Laminar and Langfuse are the two names that come up when someone wants LLM tracing they can actually own. Both are open-source. Both self-host. Both let you keep your data on your own infrastructure. So why do people pit them against each other?

Because the resemblance ends at “open source.” Langfuse is the mature, framework-agnostic default with a huge install base. Laminar is the younger, Rust-based, OpenTelemetry-native option built specifically for AI agents - especially browser agents. They solve the same problem from opposite ends. This is the honest split.

The short version

	Laminar	Langfuse
Pricing model	Data GB + Signals (tokens spent reading traces)	Billable units (traces + observations + scores)
Starting paid tier	$30/mo	$29/mo
Self-host	Whole platform, open source	Free, MIT, only 3 features gated
OpenTelemetry	Native, built on OTel	OTLP backend, HTTP only
Best for	Browser agents, long-running agents	The all-round open-source default
Maturity	2024, YC S24, $3M seed	2022 Berlin, 2,000+ paying customers

Where Laminar wins: agents, and self-hosting the whole thing

Laminar is open-source, OpenTelemetry-native, and written in Rust for low overhead. Its two real bets are performance and a deep focus on agents.

The standout feature is browser-agent observability. Laminar auto-captures browser session recordings synced with agent execution steps on a shared timeline. One line - Laminar.initialize() - and it traces the agent steps and the browser session together. Browser Use, one of the most popular open-source browser agents, documents Laminar as its observability integration. If you are building an agent that clicks around a browser, nothing else here is this targeted.

The other bet is self-host. Laminar is the only platform in this set you can self-host in full - the whole stack is open source, not just a gateway or a hobbled core. For an OTel-native tool, the credibility signal is notable too - OpenTelemetry co-creator Ben Sigelman is an angel investor, and Supabase CTO Ant Wilson is on the cap table.

The gotcha is the bill. Laminar meters on two axes - data in GB, and Signals. Signals is the feature where you describe an outcome in plain language and Laminar extracts structured events across your traces. And Signals are billed by the tokens spent reading your traces, not the tokens your agent spends. Laminar says it compresses traces to roughly 10 percent of original size to keep that cost down. The practical effect is that your bill depends on how much you interrogate your own data plus a vendor compression claim, which makes a monthly forecast genuinely hard. It is the least predictable pricing model in the category. Self-hosting removes the usage bill entirely.

One more caveat before you commit to the self-hosted build - the exact feature delta between self-host and cloud is not clearly enumerated in the docs. Managed retention and Signals billing are cloud constructs, so self-hosting clearly removes the usage bill, but confirm your must-have features survive first.

Where Langfuse wins: maturity, price you can predict, feature-complete self-host

Langfuse is the open-source default for a reason. It does four things - tracing, evals, prompt management and human annotation - without locking you to any framework. If you have asked “what is the self-hostable alternative to LangSmith,” the answer was almost certainly Langfuse.

In the self-hosted build, only three features are enterprise-gated - Organization Creators, the Instance Management API, and UI customization. Everything you actually need is free under MIT. That is far more generous than closed platforms, and unlike Laminar, the feature line is clearly drawn.

The economics are the other draw. At 1M events a month, Langfuse runs about $101/mo managed - and self-hosting removes the per-trace cost entirely. The quota unit is “billable units,” meaning traces plus observations plus scores, billed at $8 per 100k with the rate stepping down to $6 at higher volume. That is a number you can forecast, which is exactly what Laminar’s Signals model struggles with.

The catch is operational, not commercial. Langfuse v3 moved from “just Postgres” to Postgres plus ClickHouse plus Redis plus S3-compatible storage. That is four services to run, and the migration to that architecture is where self-hosters get stuck - GitHub has a string of migration threads reporting memory errors and timeouts. Also worth filing away - Langfuse was acquired by ClickHouse on 16 January 2026. The MIT license and self-host survived, but you are now betting a multi-year stack on a database company’s subsidiary. And OTLP is HTTP only - no gRPC yet.

What about Opik?

If neither fits, there is a middle path. Opik is Comet’s open-source platform, Apache-2.0, with the full feature set self-hosted and no gates - the most permissive license of the three. Its cloud Pro tier is $19/mo for 100k spans, the cheapest managed cloud in the category, which sidesteps both Laminar’s unforecastable Signals and Langfuse’s four-service self-host. The trade-off is that per-seat pricing scales poorly as your team grows, and OpenTelemetry is one ingestion path here rather than the native architecture. If you want managed hosting for the least money and a clean license, it is worth a look before you commit to either of the two above.

Laminar vs Langfuse - which should you pick?

• You are building browser agents or long-running multi-step agents - Laminar. The synced browser recordings and OTel-native tracing are purpose-built for exactly that, and self-hosting sidesteps the Signals meter.
• You want the safe, mature, framework-agnostic default - Langfuse. Bigger install base, clearer self-host feature line, and pricing you can actually forecast.
• You need pricing you can predict to the dollar on a managed tier - Langfuse over Laminar, or Opik at $19/mo if you want managed and cheap.
• Data residency is your top constraint - either one self-hosts, but Langfuse is the more battle-tested full self-host, with Laminar close behind if you confirm the feature delta first.
• You are placing a conservative multi-year bet - Langfuse for maturity, with the ClickHouse-ownership question filed away.

Both are genuinely good, and both let you self-host your way out of the vendor relationship if it sours - which is more than most of this category offers. Pick Laminar if agents are your world and you value the OTel-native, Rust-performance angle. Pick Langfuse if you want the broad default that has already been battle-tested by thousands of teams. Prices here were read from each vendor’s own pages and this category ships breaking changes monthly, so verify before you commit.