OpenAI acquired Promptfoo in March 2026. The core concern for most teams: Promptfoo's primary job was evaluating and red-teaming AI applications — and the company grading your AI outputs is now owned by one of the providers those outputs come from.
Promptfoo is a testing and red-teaming tool — it lets you run automated evals across LLM providers, test prompts against assertions, scan for vulnerabilities, and integrate safety checks into CI/CD pipelines. It runs locally, supports a wide range of LLM providers, and never required a managed service. That combination of vendor neutrality and depth is what the acquisition put in question.
Teams searching for alternatives are usually solving one of two things — or both:
Eval and red teaming
Testing prompt outputs, checking for regressions, scanning for vulnerabilities before production. Promptfoo's core territory.
Production prompt management
Versioning prompts, deploying changes without code releases, tracking what each AI feature costs, observing live behaviour. The layer that comes after testing.
Promptfoo covered the first. Most teams were handling the second with a mix of environment variables, Git, and guesswork. These are different tools for different jobs — and the right answer after the acquisition depends on which problem you're actually solving.
Endprompt is the infrastructure layer that sits between your application and the LLM. Your app calls one stable endpoint; Endprompt handles prompt rendering, the LLM call, caching, and logging. It's built for the part of the lifecycle that comes after your prompts have been tested.
Best for: Teams who want prompts managed as production infrastructure — versioned, observable, and fully decoupled from application code.
Start free trial — 14 days, no card requiredOpen-source vulnerability scanner owned and maintained by NVIDIA. Runs probes across a taxonomy of LLM failure modes — prompt injection, jailbreaking, hallucination, data leakage, and toxicity. CI/CD-compatible and model-agnostic. NVIDIA has no commercial stake in which language model you choose.
Best for: Teams that need independent, automated red teaming with no LLM vendor conflict.
Independent open-source AI red teaming and security platform. Covers hallucination testing, prompt injection detection, and RAG evaluation. European company, no frontier-model parent.
Best for: Teams that want open-source, independent red teaming with strong RAG testing support.
Endprompt
14-day free trial, no card required
Related: Prompt Versioning · Do You Need Evals? · Prompt Management API