Braintrust Review (2026)

What Braintrust actually is

Braintrust is an eval-first platform. Most tools in this category start as observability and add evals later. Braintrust started with evals and built observability around them, and it shows in the product.

It covers evals and experiments, tracing, a prompt playground, dataset management, and CI/CD quality gates. The distinctive thing is that all of it lives in one system - human review, automated scorers, LLM-as-judge, tracing and dataset management under a single roof, wired to your test pipeline. If your core problem is “did this change make the model worse, and can I block the merge if it did,” this is the platform built for that question.

The company is well-backed. Founded in August 2023 in San Francisco by Ankur Goyal, Braintrust raised a $36M Series A led by a16z in October 2024, then an $80M Series B led by Iconiq in February 2026 at a roughly $800M valuation. So it’s growing fast and funded to stay.

Regression testing is the reason to pick it

Here’s the capability that separates Braintrust from the observability crowd.

The autoevals library ships working scorers out of the box - exact match, embedding similarity, LLM-as-judge factuality - and you can drop in custom scorers as plain functions. That’s more than the primitives most tools hand you. Then the CI/CD quality gates can block a merge when a change causes a statistically significant regression. Not just log that quality dropped - actually stop the bad code from shipping.

That combination is rare. LangSmith has strong evals too, but Braintrust is the one most consistently described as the turnkey choice for regression testing. If you want quality gates in your pipeline without assembling the orchestration yourself, start here.

Pricing: watch the meter

The plans look simple. The billing model is where you need to pay attention.

Tier	Price	Included	Overage	Retention
Starter	$0	$10 credits, 1 GB data, 10k scores	$4/GB data, $2.50/1k scores	14 days
Pro	$249/mo	$249 credits, 5 GB data, 50k scores	$3/GB data, $1.50/1k scores	30 days
Enterprise	Custom	Custom	Custom	Custom

There’s no per-seat charge, which is genuinely nice - users are unlimited on every tier. But the quota unit is “processed data” in GB, and it counts every byte - inputs, outputs, prompts, metadata, traces, spans, attachments, all of it.

Two things bite here.

The meter punishes exactly the workloads that need observability most. A verbose multi-step agent or a RAG pipeline stuffing large contexts into every call generates a lot of bytes. Those are precisely the apps you most want to trace, and they burn the GB allowance fastest.

There’s no hard spending cap. As one review put it, the $0 Starter “jumps straight to $249/month with nothing in between, and no hard spending cap means you’ll exceed that amount without realizing it.” The $249 is a floor, not a ceiling. If you don’t watch the processed-data meter, the bill watches you.

Self-hosting: hybrid only, and not open source

This is the section that catches people who assume “developer tool” means “self-hostable for free.” It isn’t.

The SDKs are open source, but Brainstore - the storage and query backend - is closed. And self-hosting is a hybrid arrangement available only on Enterprise. You run the data plane inside your own VPC via Terraform: the Braintrust API, Postgres, Redis, object storage and Brainstore. Braintrust hosts the control plane for UI, metadata and auth.

The upside is real - your data never traverses Braintrust’s servers, which is exactly what a compliance-sensitive team wants. But be clear about what it isn’t. It’s not a free, open, run-it-yourself deployment like Langfuse or Helicone. You never fully own the stack, and you need an Enterprise contract to get even the hybrid version.

Braintrust versus Langfuse

The honest comparison. Braintrust is more turnkey for evals and regression testing; Langfuse is more open and cheaper.

Langfuse gives you free, MIT-licensed self-hosting and lower costs, but for full regression testing you assemble the orchestration yourself. Braintrust hands you that orchestration - autoevals, CI gates, one unified system - but you pay for it, the backend is closed, and the processed-data billing is unpredictable.

If regression testing and blocking bad merges is the job, Braintrust does it better out of the box. If open-source self-hosting and predictable cost matter more, Langfuse wins.

Should you use it?

Use Braintrust if evals and regression testing are your priority, you want CI/CD quality gates without building them yourself, and you’d rather have one unified system than stitch observability and evals together.

Don’t use Braintrust if you need free open-source self-hosting, you run verbose agents or large RAG contexts on a tight budget, or you need predictable billing - the uncapped processed-data meter is a real risk there.

Bottom line: it’s the best turnkey eval platform of the group, and if regression testing is what you came for, nothing else is this complete. Just set up billing alerts on day one. The processed-data meter has no cap, and the workloads that need Braintrust most are the ones that run it up.

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Pricing and features verified against braintrust.dev on 23 July 2026. This category ships breaking changes monthly - we re-verify every 30 days.