Langfuse vs Helicone vs Opik in 2026 - And Why One Is Off the Table

Langfuse, Helicone and Opik are all open-source LLM observability tools, all self-hostable, all pitched as the affordable alternative to closed platforms. On paper they look interchangeable. They are not - and one of them should not be on your shortlist at all in 2026.

Langfuse is the MIT-licensed default. Opik is the cheapest managed cloud with the most permissive license. Helicone is in maintenance mode after its acquisition, and Mintlify is helping customers leave. Let me take the hard call first, then the real choice.

The short version

	Langfuse	Opik	Helicone
License	MIT	Apache-2.0	Apache 2.0
Self-host	Free, near-complete	Free, full features, no gates	Free, but frozen codebase
Cheapest cloud	$29/mo	$19/mo	$79/mo
Status	ClickHouse subsidiary, active	Comet-backed, active	Maintenance mode, no roadmap
Verdict	Safe default	Cheapest, cleanest license	Do not start here

Helicone: do not start here

I am including Helicone mainly to tell you not to build on it. It was a clean, open-source, proxy-based observability tool. Then Mintlify acquired it on 3 March 2026 and put it in maintenance mode - security patches, bug fixes and new-model support only, no roadmap, and Mintlify is actively helping customers migrate off.

For a new buyer, that single fact overrides everything else. The Apache 2.0 self-host still works, but self-hosting a frozen codebase whose own creator is pointing people to the exit is a weak bet - you would be maintaining software that only gets security fixes. The proxy model was also a structural single point of failure - if Helicone is down, your LLM calls fail even when the provider is healthy, and every proxied call adds latency, which Helicone cites at around 10ms. There is an async SDK logging mode that dodges both, but then you lose the zero-code convenience that was the main reason to pick Helicone in the first place. At acquisition it had processed 14.2 trillion tokens across roughly 16,000 organizations, so it was a real product. It is just not one to start on now. If you are already on it, plan your exit.

Langfuse: the safe open-source default

Langfuse is the open-source default because self-hosting gets you the real product. Only three features are enterprise-gated in the self-host build - Organization Creators, the Instance Management API, and UI customization. Tracing, evals, prompt management, human annotation and RBAC are all free under MIT. The economics are the other draw - at 1M events a month it runs about $101/mo managed, and self-hosting removes the per-trace cost entirely. It is framework-agnostic and runs as an OpenTelemetry backend.

The catch is operational, not commercial. Langfuse v3 needs Postgres plus ClickHouse, Redis and S3-compatible storage - four services - and the migration to that architecture is where self-hosters get stuck. OTLP is HTTP only, no gRPC yet. It is now a ClickHouse subsidiary after the 16 January 2026 acquisition, which preserved the MIT license and self-host but is worth weighing for a multi-year bet. The $29/mo Core cloud tier sidesteps the four-service stack if you cannot spare the ops time. This is the most battle-tested pick of the three - founded in 2022, with over 2,000 paying customers at acquisition.

Opik: the cheapest cloud, cleanest license

If the appeal of Langfuse is the openness but you would rather not run four services, Opik is the move. It is Comet’s open-source observability and eval platform, and it does something no one else here quite matches - the OSS build is Apache-2.0 with the full feature set self-hosted, unlimited spans, members and retention, no gates. That is the most permissive setup in this trio.

On the cloud, Pro is $19/mo for 100k spans, the cheapest paid tier of the major platforms, with $5 per additional 100k. The Free cloud tier gives you 25k spans a month, up to 10 members and 60-day retention. It is also the fastest-growing project of its peers at roughly 20.8k GitHub stars, and it is backed by Comet, an established company since 2017 with roughly $63M raised - so this is not a solo side project.

The gotcha is per-seat pricing at scale. The $19 headline is the small-team configuration, and the recurring complaint is that seat costs climb as the team grows. A few users also report occasional UI slowdown on very large projects. And OpenTelemetry is one ingestion path here, not the native architecture - fine for most stacks, worth noting if you are standardizing strictly on OTel. None of that undercuts the core value - just model the seat cost if you are a big team.

Which should you pick?

• You want the safe, battle-tested open-source default and can run the self-host stack - Langfuse. Biggest install base, clearest self-host feature line, and the MIT license means you are never stranded.
• You want managed hosting for the least money, with a clean license - Opik at $19/mo. Also the pick if you want a full-featured self-host with no gates and no license asterisk.
• You are a large team sensitive to per-seat cloud pricing - model Opik’s seat cost first, and consider Langfuse Core at $29/mo with unlimited users as a hedge.
• You are on Helicone today - use the runway to plan your exit. Do not start there fresh.
• You are evaluating observability tools right now in 2026 - it is a two-horse race between Langfuse and Opik. Helicone is out.

The honest close - Langfuse and Opik are both genuinely good, genuinely open, and genuinely cheap, and you would be well served by either. Pick Langfuse for maturity and the deepest self-host track record. Pick Opik for the cheapest cloud and the most permissive license. And whatever you do, do not start a new project on Helicone - its own owner is helping people leave. Prices here were read from each vendor’s own pages, and this category ships breaking changes monthly, so re-verify before you commit.