Flakestorm vs PromptFoo
Comparing chaos engineering for AI agents with comprehensive AI security testing
Quick Comparison
| Feature | Flakestorm | PromptFoo |
|---|---|---|
| Primary Focus | Chaos engineering and robustness testing for AI agents | Comprehensive AI security testing (red teaming, guardrails, model security, evaluations) |
| Pricing | Open-source (free) + Pro ($49/month) + Team ($299/month). Transparent, affordable pricing. | Open-source Community plan (free) + Enterprise (custom pricing, contact sales) |
| Best For | Agent robustness validation, mathematical reliability scoring, local testing | Enterprise AI security, red teaming, real-time guardrails, comprehensive vulnerability testing |
| Testing Approach | Chaos engineering: automatic adversarial mutation generation | Red teaming: context-aware attacks tailored to your application |
| Vulnerability Coverage | 5 mutation types (open-source), 15 types (cloud): paraphrase, noise, tone shift, prompt injection, PII detection | 50+ vulnerability types: prompt injections, jailbreaks, data leaks, business rule violations, insecure tool use, toxic content |
| Scoring System | Mathematical robustness score (0.0-1.0) based on invariant violations | Pass/fail with custom assertions (JavaScript, regex, contains), security findings |
| Agent Testing | Complete agent systems (HTTP, Python callables, LangChain) | Agents, RAGs, workflows, MCP, API endpoints |
| Additional Features | Robustness scoring, local execution, CI/CD blocking | Real-time guardrails, code scanning, MCP proxy, model security monitoring |
| Local Execution & Costs | Runs entirely on your machine with Ollama, zero API costs, unlimited testing, complete privacy | Can run locally but typically requires external LLM APIs (costs money per test, data sent to third parties) |
| CI/CD Integration | Built for blocking PRs when robustness scores drop below thresholds (mathematical quality gates) | Full CI/CD integration with GitHub, GitLab, Jenkins; security findings in PRs (pass/fail based) |
| Test Case Creation | Fully automatic - generates 50+ mutations per prompt from a single golden prompt, no manual work required | Can generate custom attacks but requires configuration and test case setup |
Why Choose Flakestorm Over PromptFoo?
Cost-Effective & Transparent Pricing
Flakestorm: Open-source is completely free. Pro ($49/month), Team ($299/month). Transparent pricing, no hidden costs, no API fees. PromptFoo:Community plan is free, but Enterprise requires contacting sales for custom pricing (not publicly disclosed).
Mathematical Robustness Score
Flakestorm provides a quantifiable 0.0-1.0 robustness score you can track over time, set CI/CD thresholds, and prove reliability to stakeholders. PromptFoo gives pass/fail results without a unified reliability metric.
Zero API Costs & Complete Privacy
Run Flakestorm entirely locally with Ollama - no data leaves your machine, no API costs, unlimited testing. PromptFoo can run locally but typically uses external LLM APIs for testing, which may incur costs and send data to third-party services.
Automatic Mutation Generation
Flakestorm automatically generates 50+ adversarial mutations per prompt - no manual test case creation needed. PromptFoo can generate custom attacks, but still requires configuration and test case setup, while Flakestorm's mutations are fully automatic from a single golden prompt.
Focused & Simple
Flakestorm does one thing exceptionally well: prove agent robustness. Simple setup, clear results. PromptFoo is a comprehensive platform with many features you may not need, adding complexity.
Built for CI/CD Quality Gates
Flakestorm is designed specifically to block PRs when robustness scores drop below thresholds. The mathematical score makes it easy to set and enforce quality gates.PromptFoo can integrate with CI/CD but lacks a unified scoring system for automated gates.
When to Choose Flakestorm
- You need mathematical proof of agent reliability (robustness score)
- You want zero API costs and complete privacy (local execution)
- You need automatic adversarial mutation generation (no manual test cases)
- You want affordable, transparent pricing ($49-$299/month vs custom enterprise pricing)
- You need CI/CD integration with score-based quality gates
- You're testing complete agent systems (HTTP, Python, LangChain)
- You want a focused, simple tool that does one thing well
- You need to track robustness over time with quantifiable metrics
When to Choose PromptFoo
- You need enterprise-grade AI security with 50+ vulnerability types
- You want real-time guardrails and protection in production
- You need comprehensive red teaming for agents and RAG systems
- You require code scanning for LLM vulnerabilities in your IDE
- You need model security monitoring and compliance (HIPAA, FINRA, SOC2)
- You're building at enterprise scale and need proven solutions
- You want MCP proxy and advanced integrations
Key Differences
Testing Philosophy
Flakestorm takes a chaos engineering approach with mathematical robustness scoring, focusing on proving agent reliability through systematic adversarial testing. PromptFootakes a comprehensive security approach with red teaming, real-time guardrails, and enterprise-grade protection, covering 50+ vulnerability types.
Scope & Features
Flakestorm specializes in agent robustness testing with automatic mutation generation and mathematical scoring. It excels at local execution and CI/CD blocking based on robustness scores.PromptFoo offers a complete AI security platform including red teaming, guardrails, model security monitoring, code scanning, MCP proxy, and enterprise compliance features.
Key Differentiators
Flakestorm is ideal for teams wanting mathematical proof of agent reliability, zero-cost local testing, automatic mutation generation, and affordable transparent pricing ($49-$299/month). The unique robustness score (0.0-1.0) enables quantifiable quality gates in CI/CD pipelines.
PromptFoo is ideal for large enterprises needing comprehensive security coverage, real-time guardrails, and compliance features. Enterprise pricing requires contacting sales (custom pricing, not publicly disclosed). Both tools test agents and RAGs, but Flakestorm emphasizes mathematical robustness scoring and cost-effectiveness, while PromptFoo emphasizes comprehensive security coverage and enterprise-scale features.
Complementary Use Cases
These tools can work together: Use Flakestorm for rapid local development testing and robustness validation, then use PromptFoo for comprehensive security testing, real-time guardrails, and enterprise compliance before production deployment.