letta vs promptfoo

Side-by-side comparison of two AI agent tools

lettaopen-source

Letta is the platform for building stateful agents: AI with advanced memory that can learn and self-improve over time.

promptfooopen-source

Test your prompts, agents, and RAGs. Red teaming/pentesting/vulnerability scanning for AI. Compare performance of GPT, Claude, Gemini, Llama, and more. Simple declarative configs with command line and

Metrics

lettapromptfoo
Stars21.8k18.9k
Star velocity /mo367.51.7k
Commits (90d)
Releases (6m)1010
Overall score0.74668152545311320.7957593044797683

Pros

  • +Advanced persistent memory system that allows agents to learn and self-improve across sessions
  • +Dual deployment options with both local CLI tool and cloud API for different use cases
  • +Model-agnostic platform with comprehensive SDKs for Python and TypeScript development
  • +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

Cons

  • -Requires Node.js 18+ for local CLI usage, limiting accessibility for some users
  • -Cloud API requires API key and external service dependency for full functionality
  • -Platform complexity may present learning curve for developers new to stateful agent concepts
  • -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

Use Cases

  • Building long-term coding assistants that remember project context and user preferences across sessions
  • Creating customer service agents that maintain conversation history and learn from interactions
  • Developing research assistants that accumulate domain knowledge and improve recommendations over time
  • 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