kitio.aiPromptfoo vs TruLens
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. TruLens is completely free, while Promptfoo is freemium.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Config-based test cases
- Model comparison
- Red-team scans
- CI integration
- Web results viewer
- OpenTelemetry tracing
- LLM judge evaluations
- RAG triad metrics
- Custom rubrics
- Multi-turn conversation evals
| Feature | Promptfoo | TruLens |
|---|---|---|
| Best for | Open-source CLI for testing prompts and red-teaming AI apps | Open-source evals and OpenTelemetry tracing for AI agents and RAG |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Free |
| Starting price | See pricing page | Free |
| Free plan | Yes | Yes, fully free |
| Made by | OpenAI | Snowflake |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
TruLens is completely free, while Promptfoo is freemium.
Free plan
Cheapest paid plan
Top plan
Free trial
2 plans
Community
Free
- Open source
- All LLM evaluation features
- Red teaming (10k probes/month)
- Run locally or self-host
Enterprise
Contact sales
- Reports and continuous monitoring
- Issue tracking and remediation
- Dedicated runner
- Assigned deployment engineer
Prices in USD, checked Oct 28, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Promptfoo
- Free and works with any provider
- Strong security testing
- Fits developer workflows
- Owned by a model vendor now
- CLI-first may not suit everyone
- Enterprise pricing not public
TruLens
- Free and open source
- Judges explain each score
- Standard OpenTelemetry traces
- Python library, not a hosted product
- Judge scoring adds LLM costs
- Custom metrics require writing code
Which one should you choose?
Choose Promptfoo if you want:
- Free and works with any provider
- Strong security testing
- Fits developer workflows
Watch out: owned by a model vendor now.
Choose TruLens if you want:
- Free and open source
- Judges explain each score
- Standard OpenTelemetry traces
Watch out: python library, not a hosted product.
Promptfoo vs TruLens FAQ
What is the difference between Promptfoo and TruLens?
Promptfoo: Open-source CLI for testing prompts and red-teaming AI apps. TruLens: Open-source evals and OpenTelemetry tracing for AI agents and RAG. Both are models & apis tools.
Is Promptfoo or TruLens cheaper?
TruLens is completely free, while Promptfoo is freemium.
Do Promptfoo and TruLens have free plans?
Promptfoo: Yes. TruLens: Yes, fully free.
Who makes Promptfoo?
Promptfoo is made by OpenAI, based in United States.
Who makes TruLens?
TruLens is made by Snowflake, based in United States.
Which should I choose, Promptfoo or TruLens?
Choose Promptfoo if you value free and works with any provider and strong security testing. Choose TruLens if you value free and open source and judges explain each score.