Honest pros, cons, and verdict on this testing & quality tool
✅ Comprehensive red-teaming fills a critical gap in LLM safety tooling
Starting Price
Free
Free Tier
No
Category
Testing & Quality
Skill Level
Developer
Open-source LLM testing and evaluation framework for systematically testing prompts, models, and AI agent behaviors with automated red-teaming.
Promptfoo is an open-source testing and evaluation framework designed to help developers systematically test LLM applications, prompts, and AI agent behaviors. It provides a CLI-driven workflow for defining test cases, running evaluations across multiple models and prompt variants, and comparing results with automated scoring — essential for building reliable AI agents that behave predictably in production.
The framework supports a wide range of assertion types including exact matching, semantic similarity, model-graded evaluations, and custom JavaScript/Python assertions. Developers can test across multiple LLM providers simultaneously, comparing how different models handle the same prompts and scenarios. This is particularly valuable for agent development where choosing the right model for each task is critical.
per month
per month
AI observability platform with Loop agent that automatically generates better prompts, scorers, and datasets from production data. Free tier available, Pro at $25/seat/month.
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Learn more →LangSmith lets you trace, analyze, and evaluate LLM applications and agents with deep observability into every model call, chain step, and tool invocation.
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Learn more →Former LLMOps platform for prompt engineering and evaluation, acquired by Anthropic in August 2025. Technology now integrated into Anthropic Console as the Workbench and Evaluations features.
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Learn more →Promptfoo delivers on its promises as a testing & quality tool. While it has some limitations, the benefits outweigh the drawbacks for most users in its target market.
Open-source LLM testing and evaluation framework for systematically testing prompts, models, and AI agent behaviors with automated red-teaming.
Yes, Promptfoo is good for testing & quality work. Users particularly appreciate comprehensive red-teaming fills a critical gap in llm safety tooling. However, keep in mind openai acquisition may affect future open-source direction.
Promptfoo starts at Free. Check their pricing page for the most current rates and features included in each plan.
Promptfoo is best for Security teams needing to red-team LLM applications before deployment and Development teams comparing prompt performance across multiple models. It's particularly useful for testing & quality professionals who need advanced features.
Popular Promptfoo alternatives include Braintrust, LangSmith, Humanloop. Each has different strengths, so compare features and pricing to find the best fit.
Last verified March 2026