Promptfoo is an open-source platform designed to help developers test, evaluate, and secure large language model (LLM) applications. It offers tools for automated red teaming, vulnerability scanning, and continuous monitoring, enabling users to identify issues such as prompt injections, data leaks, and harmful content. With a command-line interface and support for declarative configurations, Promptfoo integrates seamlessly into development workflows, allowing for efficient testing across various LLM providers. Trusted by over 75,000 developers, including teams at Shopify, Discord, and Microsoft, Promptfoo emphasizes local operation to ensure privacy and is supported by an active open-source community.