Opik Pricing in 2026 - The Cheapest Cloud, Decoded

Opik is the rare tool where the pricing is the headline feature, not the fine print. Its Pro cloud tier is $19/mo for 100k spans - the cheapest paid cloud of the major eval platforms - and the self-hosted build is free under Apache-2.0 with the full feature set and no gates. That is the whole pitch, and it holds up. But there is one real trap in the meter, and there are cases where paying more for a different tool is the right call. Let me decode it.

The tiers

Tier	Price	Spans	Members	Retention
Open Source	$0	unlimited	unlimited	unlimited
Free Cloud	$0	25k/mo	up to 10	60 days
Pro Cloud	$19/mo	100k/mo	up to 50	60 days
Enterprise	Contact sales	unlimited	unlimited	custom

The quota unit is spans per month, plus members (seats). A span is one step in a trace - an LLM call, a tool execution, an agent action - so a multi-step agent generates several spans per request. That matters for the estimate below.

The Open Source build is the standout. Opik OSS is Apache-2.0, the most permissive license in the category, and Comet states the self-hosted version ships the full feature set with unlimited spans, members and retention - no gates. It is designed to self-host at Kubernetes scale without losing features. So if you can run it, the real product is free. The cloud tiers add managed hosting, compliance certs, SSO and support, not core capability.

On the cloud, the Free tier is a genuine working tier, not a trial - 25k spans a month, up to 10 members, 60-day retention. Enough to run a small production app.

Estimate your Pro bill

This is the part most pricing pages make hard and Opik makes easy, because the overage rate is published: $5 per additional 100k spans above the 100k included in Pro.

Say you run an agent app that averages 5 spans per request and handles 100,000 requests a month. That is 500,000 spans. Pro includes the first 100k, leaving 400k of overage. At $5 per 100k, that is $20 of overage on top of the $19 base.

Your bill: about $39/mo for half a million spans. That is the kind of number that makes Opik the cheapest managed option here - the same span volume on most competitors costs multiples of it.

Two line items to fold in. Retention on the cloud defaults to 60 days; extending it to as far as 400 days costs $29 per 100k spans, so long retention is a real add-on, not free. And the annual discount is not stated on the pricing page, so budget monthly.

The trap: per-seat pricing at scale

The honest weakness is not the span meter - it is the seats. The recurring complaint is that per-seat pricing scales poorly for larger teams. Pro allows up to 50 members, and smaller startups report that the cost gets hard to justify as headcount rises, even though the entry price is low. The $19 headline is the small-team configuration, not the large one.

A few users also report occasional UI slowdown on very large projects. Neither issue undercuts the core value, but the shape of the bill changes as you add people rather than as you add spans. If you are a big team, model the seat cost before you commit - or self-host, which removes the seat meter entirely. That Apache-2.0 build with unlimited members is exactly the escape hatch a growing team wants, and Opik is one of the few tools that gives it to you with no feature loss.

When to pay more for a different tool

Opik is the cheapest, but cheapest is not always right. Two cases where I would spend more.

You want full regression testing and CI quality gates: Braintrust. Braintrust is eval-first, and its CI/CD gates can block a merge on a statistically significant regression, not just log that quality dropped. Opik has real eval - LLM-as-judge, code metrics, online evaluation, guardrails, an Agent Optimizer - but if blocking bad merges is the center of gravity, Braintrust is more turnkey. The cost is real, though: Braintrust bills “processed data” in GB counting every byte, with no hard spending cap, and the $0 Starter jumps straight to $249/mo with nothing in between. Verbose agents and big RAG contexts burn that allowance fastest. Set billing alerts on day one. This is a case where you pay more and accept less predictable billing for a more complete regression workflow.

You want the most transparent open-source default: Langfuse. Langfuse Core is $29/mo for 100k billable units, then $8 per 100k - slightly pricier than Opik’s cloud, but it is MIT-licensed and the reference “self-hostable alternative to LangSmith.” At 1M events a month it runs about $101/mo managed, per Langfuse’s pricing. Its self-host catch is operational: v3 needs Postgres plus ClickHouse, Redis and S3-compatible storage, four services to run. Opik’s self-host is generally simpler to stand up, which is a point in Opik’s favor if ops capacity is thin. But if you want the most established open-source name and MIT specifically, Langfuse is the safer institutional bet.

So which one?

• You want the cheapest managed cloud, full stop - Opik Pro at $19/mo for 100k spans, with published $5 per 100k overage.
• You are a growing team worried about seats - self-host Opik under Apache-2.0, unlimited members, no seat meter.
• Blocking bad merges is the priority - Braintrust, with billing alerts on from day one for the uncapped GB meter.
• You want the MIT-licensed open-source default - Langfuse, if you can run the four-service self-host.

One honest note on the numbers. Every price here is from each vendor’s public pages, and this category ships breaking changes monthly - we re-verify every 30 days. The one figure that decides most budget-led choices, the $19/mo Opik Pro tier against everyone else’s entry cloud, has held for a while. If price is why you are here, Opik is hard to beat - just watch the seats, not the spans.