Which is more popular, Guardrails or Promptfoo?

Promptfoo has more GitHub stars (25,665 vs 7,237).

Which is more actively developed, Guardrails or Promptfoo?

Promptfoo had more commits in the last 90 days (920 vs 122).

Compare their capabilities, limitations and "best for" notes above. Trying each on a small task is the fastest way to decide.

Side-by-side comparison of two AI agent tools

Promptfoo is growing faster: +1,110 GitHub stars in the last 30 days vs +217 for Guardrails.
Pick Guardrails for: neMo Guardrails is an open-source toolkit for easily adding programmable guardrails to LLM-based. Pick Promptfoo for: open-source CLI and library for evaluating and red-teaming prompts, agents, RAG systems, and LLM apps.

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NeMo Guardrails is an open-source toolkit for easily adding programmable guardrails to LLM-based conversational systems.

Promptfooopen-source

Open-source CLI and library for evaluating and red-teaming prompts, agents, RAG systems, and LLM apps

+Open-source toolkit backed by NVIDIA with comprehensive documentation and active development
+Flexible programming model supporting multiple types of guardrails from content filtering to structured data extraction
+Production-ready with multi-platform support (Linux, Windows, macOS) and extensive testing infrastructure

+Comprehensive testing suite covering both performance evaluation and security red teaming in a single tool
+Multi-provider support with easy comparison between OpenAI, Anthropic, Claude, Gemini, Llama and dozens of other models
+Strong CI/CD integration with automated pull request scanning and code review capabilities for production deployments

-Requires C++ dependencies (annoy library) which may complicate deployment in some environments
-Additional complexity layer that may impact response latency in high-throughput applications
-Learning curve for configuring effective guardrails rules and understanding the programming model

-Requires API keys and credits for multiple LLM providers, which can become expensive for extensive testing
-Command-line focused interface may have a learning curve for teams preferring GUI-based tools
-Limited to evaluation and testing - does not provide actual LLM application development capabilities

•Content moderation for customer service chatbots to prevent discussions of sensitive topics like politics or inappropriate content
•Enforcing specific dialog flows and response formats for structured interactions like form filling or guided troubleshooting
•Extracting and validating structured data from conversational inputs while maintaining consistent output formatting

•Automated testing and evaluation of prompt performance across different models before production deployment
•Security vulnerability scanning and red teaming of LLM applications to identify potential risks and compliance issues
•Systematic comparison of model performance and cost-effectiveness to optimize AI application architecture

Which is more popular, Guardrails or Promptfoo?: Promptfoo has more GitHub stars (25,665 vs 7,237).
Which is more actively developed, Guardrails or Promptfoo?: Promptfoo had more commits in the last 90 days (920 vs 122).
Should I use Guardrails or Promptfoo?: Compare their capabilities, limitations and "best for" notes above. Trying each on a small task is the fastest way to decide.