Portkey vs Promptfoo (2026)
Updated March 10, 2026
Overview
Portkey provides LLM observability alongside its gateway capabilities, offering detailed logging, metrics, and tracing for LLM API calls. Teams can monitor latency, costs, token usage, and error rates across providers, with request-level debugging and analytics dashboards for production AI applications.
Promptfoo is an open-source tool for testing and evaluating LLM prompts. It lets developers define test cases, run them against multiple models, compare outputs side-by-side, and catch regressions before deployment. Supports custom scoring functions, red-teaming, and CI/CD integration for automated prompt testing.
Strengths and tradeoffs
What each tool does well, and the limitations to keep in mind.
Pros
- Enterprise-scale monitoring (10B requests/month)
- Sub-40ms overhead
- Comprehensive analytics and tracing
- Strong security certifications
Cons
- Professional tier expensive (USD 2-5k/mo)
- Open-source has limited features
- Complex for small teams
Pros
- Completely free and open source (MIT license)
- Fast with quality features like live reloads and caching
- Built-in red teaming and security vulnerability scanning
- Trusted by large companies with strong community
Cons
- CLI-focused creates friction for non-technical users
- Limited observability for complex production agents
- No version control for prompts, data, or metrics
- Offline nature hits ceiling for production scale
Compare Portkey and Promptfoo on your own traffic
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.
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