OpenAI Evals vs Promptfoo
If you are wiring up LLM tests, you have probably found both of these. OpenAI Evals is a registry-based framework. You define evals and run them against a model, and the design grew up around OpenAI's own ecosystem. Promptfoo is a config-driven runner that stays model-agnostic. You point one config file at many providers and compare outputs side by side.
| Dimension | OpenAI Evals | Promptfoo |
|---|---|---|
| What it is | An eval framework with a shared eval registry | A config-driven, model-agnostic eval runner |
| License | Open source | Open source |
| You write evals as | Registry entries plus Python | YAML config, with JS/TS when needed |
| Model coverage | OpenAI-centric by design | Many providers, built to compare |
| Feels like | Contributing to an eval library | A CLI you point at prompts and models |
| CI integration | Workable, less turnkey | Strong, built to run as a gate |
| Red-teaming | Not the focus | Yes, a real strength |
| Best for | Deep OpenAI eval work and shared benchmarks | Cross-model comparison and a fast CI gate |
You build mainly on OpenAI, you want to write evals in Python, or you want to draw on a shared registry of eval templates. OpenAI Evals fits teams who live inside that ecosystem and want their evals close to it.
You want to compare several models against the same prompts, or you need an eval gate running in CI this week without committing to one vendor. Promptfoo gets you from a config file to a passing gate fast, and the red-teaming is a real bonus.
For most teams starting evals today, I reach for Promptfoo. The config-first workflow and cross-model comparison get you to a real CI gate faster, and staying model-agnostic matters because most teams end up testing more than one model. OpenAI Evals is the better home if your world is OpenAI and you want Python evals plus the shared registry. The common mistake is picking by whose logo is on the box instead of by how the tool actually works. What moves the needle is writing ten honest test cases and wiring them into CI. Either tool does that.