Opik vs Promptfoo: Observability, Prompts & Evals Comparison
Compare Opik and Promptfoo side by side. Both are tools in the Observability, Prompts & Evals category.
Updated March 10, 2026
The short answer
Choose Opik if production-ready.
Choose Promptfoo if completely free and open source (MIT license).
Want to compare Opik 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 250+ models through one gateway. Free tier covers 10K traces per month. Setup in 5 minutes, no credit card.
Quick Comparison
| Category | Observability, Prompts & Evals | Observability, Prompts & Evals |
| Website | comet.com | promptfoo.dev |
Pros & Cons: Opik vs Promptfoo
- +Production-ready
- +Good performance
- +Active development
- −Pricing varies
- −Setup required
- +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
- −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
Pricing: Opik vs Promptfoo
- · Core features
- · Community support
- · Advanced features
- · Priority support
- · Custom solutions
- · SLA guarantees
- · MIT license
- · Up to 10k probes/month
- · All core features
- · CLI and browser UI
- · Hosting costs
- · Database expenses
- · LLM API calls
- · Variable by usage
- · Advanced features
- · Higher probe limits
- · Priority support
- · Custom security
About Opik
AI platform providing comprehensive solutions for enterprise applications. The platform provides essential capabilities for modern AI applications with focus on scalability and reliability.
About Promptfoo
Promptfoo is an open-source tool for testing prompts, agents, and RAGs, with AI red teaming, pentesting, and vulnerability scanning for LLMs. Built under MIT license, Promptfoo was originally developed for LLM apps serving over 10 million users in production. The platform compares performance across GPT, Claude, Gemini, Llama, and more with simple declarative configs supporting command line and CI/CD integration. The Community version includes up to 10,000 probes monthly at no charge, with infrastructure costs typically USD 50-500 monthly for hosting and LLM API calls. Developers praise Promptfoo for its speed, quality-of-life features like live reloads and caching, security features including red teaming, and budget-friendly open-source model. However, the CLI-focused approach creates friction for non-technical team members, and the platform lacks end-to-end observability, version control for prompts, and test management features needed for complex production agents.
What is Observability, Prompts & Evals?
Tools for monitoring LLM applications in production, managing and versioning prompts, and evaluating model outputs. Includes tracing, logging, cost tracking, prompt engineering platforms, automated evaluation frameworks, and human annotation workflows.
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