Braintrust vs Evidently
Both are eval frameworks tools. Here is how they actually differ on price, billing model and deployment.
Braintrust
The most complete eval-first platform - evals, experiments, CI/CD quality gates and observability in one system. The catch is a processed-data-GB billing meter that's uncapped and punishes verbose agents.
Evidently
An open-source ML and LLM evaluation framework with 100+ metrics spanning tabular data through to GenAI. Notably, release 0.7.17 moved previously closed functionality into open source - the opposite of the usual direction.
| Braintrust | Evidently | |
|---|---|---|
| Category | Eval Frameworks | Eval Frameworks |
| Our rating | 4/5 | 4/5 |
| Starting price | $249/mo | Not published |
| Billing meter | span | No usage metering |
| Free plan | Yes | Yes |
| Free self-hosting | No or paid tier only | Yes, free |
| Best for | Teams that want turnkey regression testing and CI/CD quality gates without assembling the eval orchestration themselves | Teams evaluating classical ML and LLM systems together, especially where data drift and data quality matter as much as output quality, and who want CI-integrated declarative testing. |
Our verdict on Braintrust
The best turnkey eval platform of the four - if regression testing and blocking bad merges is your priority, nothing else is this complete out of the box. The gotcha is the billing model - processed data is metered by the byte with no spending cap, so the verbose agents and large RAG contexts that most need observability are exactly what blows up the bill. Watch the meter, or the $249 plan won't stay $249.
Full Braintrust review →Our verdict on Evidently
Evidently is the broadest evaluation framework in this category and the only one that treats data quality, classical ML performance and LLM output as one continuous problem. That breadth is the reason to choose it. A team running recommender systems and a RAG assistant gets drift detection, ranking metrics and hallucination checks from one library with 100+ built-in metrics, where a purely LLM-native tool would cover a third of the surface. The design is also good - any Report becomes a Test Suite by adding pass/fail conditions, which makes CI gating a natural extension rather than a separate product. And release 0.7.17 moved previously closed functionality into open source, including the service for storing run logs and LLM-judge workflows, which is the opposite of the direction open-core vendors normally travel and deserves credit. The clear weakness is agents. There is no span-level evaluation for scoring individual steps like tool calls, no graph visualisation of execution paths, and agent evaluation needs custom work. If agents are your primary workload, look elsewhere.
Full Evidently review →Frequently Asked Questions
What is the main difference between Braintrust and Evidently?
Braintrust: Teams that want turnkey regression testing and CI/CD quality gates without assembling the eval orchestration themselves Evidently: Teams evaluating classical ML and LLM systems together, especially where data drift and data quality matter as much as output quality, and who want CI-integrated declarative testing. Both sit in Eval Frameworks, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Braintrust or Evidently?
It depends entirely on your workload shape, because they meter differently - Braintrust bills on span and Evidently bills on no usage metering. Published starting prices are $249/mo and Not published respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Braintrust or Evidently?
Braintrust: No or paid tier only. Evidently: Yes, free. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.