Promptfoo

In 2026, choosing the wrong LLM evaluation tool is as costly as shipping bad code. The LLM observability market hit $2.69 billion this year and is projected to reach $9.26 billion by 2030. Gartner estimates that 50% of all GenAI deployments will rely on LLM observability platforms by 2028. Three tools dominate the conversation: DeepEval, a Python-native open-source framework with 14 built-in research-backed metrics; Braintrust, a production monitoring and eval lifecycle platform fresh off an $80M Series B at an $800M valuation; and PromptFoo, a security-focused testing tool that OpenAI acquired in March 2026. Each solves a genuinely different problem, and picking the right one depends entirely on where your evaluation gaps actually are. ...

OpenAI acquiring PromptFoo is not a talent grab — it is a strategic acknowledgment that AI security testing is no longer optional infrastructure. With 93% of organizations now shipping AI-generated code and only 12% applying equivalent security standards, the attack surface is enormous and growing. PromptFoo was the most mature open-source tool purpose-built for LLM red-teaming, and OpenAI buying it means the company is betting that security evaluation needs to be a first-class part of the developer workflow, not an afterthought bolted on by a third-party CLI. ...