Promptfoo vs UpTrain
Both are eval frameworks tools. Here is how they actually differ on price, billing model and deployment.
Promptfoo
The de-facto open-source CLI for LLM eval and red-teaming, driven by declarative YAML. MIT-licensed, ~23.5k stars, and acquired by OpenAI in March 2026 - still open source, now part of OpenAI Frontier.
UpTrain
An Apache-2.0 evaluation library with a hosted grading API and dashboard. Its distinguishing feature is root cause analysis on failures rather than just scoring them - but the commercial signals around it are thin.
| Promptfoo | UpTrain | |
|---|---|---|
| Category | Eval Frameworks | Eval Frameworks |
| Our rating | 4/5 | 3/5 |
| Starting price | $0 | $0 (open source) |
| Billing meter | No usage metering | No usage metering |
| Free plan | Yes | Yes |
| Free self-hosting | Yes, free | Yes, free |
| Best for | Security and CI teams who want config-driven LLM eval plus serious red-teaming, from an OSS tool with no seat cost | Teams who want a permissively licensed eval library with a broad named check set and value failure explanations over raw scores, and who are comfortable adopting a smaller project. |
Our verdict on Promptfoo
The clearest pick if red-teaming and security testing are part of your eval story, and its YAML-in-git approach fits CI cleanly. The OpenAI acquisition in March 2026 is the thing to weigh - the commitment to stay MIT is on the record, but you are now betting on OpenAI's stewardship of the project. For the free tier alone it is still an easy yes.
Full Promptfoo review →Our verdict on UpTrain
UpTrain has one genuinely good idea and a thin commercial story around it. The good idea is root cause analysis - rather than reporting that a factual accuracy check scored 0.4, it attempts to explain why, which is the difference between a metric and a diagnosis. That is a real gap in the category, since the standard output of an eval framework is a number that tells you something is wrong but not what to change. The named check set is also broad and sensibly chosen, covering context relevance, factual accuracy, completeness, conciseness, tonality, prompt injection and hallucination, with tonality being unusual and genuinely useful for consumer products. The concerns are around adoption and clarity. A G2 profile claiming over a million responses evaluated but carrying zero reviews is a weak signal, the managed API's pricing is listed as not applicable rather than published, and the API sits at version 0.7.1, which is pre-1.0. It is Apache 2.0, so the downside is bounded, but Ragas and DeepEval are safer defaults.
Full UpTrain review →Frequently Asked Questions
What is the main difference between Promptfoo and UpTrain?
Promptfoo: Security and CI teams who want config-driven LLM eval plus serious red-teaming, from an OSS tool with no seat cost UpTrain: Teams who want a permissively licensed eval library with a broad named check set and value failure explanations over raw scores, and who are comfortable adopting a smaller project. Both sit in Eval Frameworks, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Promptfoo or UpTrain?
It depends entirely on your workload shape, because they meter differently - Promptfoo bills on no usage metering and UpTrain bills on no usage metering. Published starting prices are $0 and $0 (open source) 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 Promptfoo or UpTrain?
Promptfoo: Yes, free. UpTrain: Yes, free. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.