Promptfoo vs Weights & Biases: Which is Better in 2026?
Choosing between Promptfoo and Weights & Biases comes down to understanding what each tool does best. This comparison breaks down the key differences so you can make an informed decision based on your specific needs, not marketing claims.
Bottom line: Weights & Biases wins this matchup. Pick Promptfoo if you need security.
Short on time? Here's the quick answer
Based on published vendor pricing and features and on public review data, here's who should pick what:
Promptfoo
Build secure AI applications with AI security testing integrated into your development workflow.
Best for you if:
- • You want LLM eval framework
Weights & Biases
Track, compare, and share ML experiments and models
Best for you if:
- • You want great visualizations
| At a Glance | Weights & Biases | |
|---|---|---|
Starts at | Free Free plan | Free Free plan |
Category | Security Testing & QA | Analytics Data Visualization |
Rating | n/a | 4.6/5 G2 4.6 57 reviews |
Free plan | Yes | Yes |
Watch out for | No public overage pricing for Cloud | Overage fees for storage/Weave data on Free tier |
Choose Promptfoo or Weights & Biases?
Choose Promptfoo if
- You want LLM eval framework
- You want open source
- Budget matters (Free vs Free)
- You work in security, not analytics
Choose Weights & Biases if
- You want great visualizations
- You want team collaboration
- You work in analytics, not security
In-Depth Analysis
Promptfoo
Build secure AI applications with AI security testing integrated into your development workflow.
The pricing for Promptfoo is very generous, especially with a robust free tier offering unlimited local evals and all features.
Watch out
No public overage pricing for Cloud
Strengths
- Pro: LLM eval framework
- Pro: Open source
- Pro: Good for testing prompts
- Pro: Active development
- Pro: Good documentation
Weaknesses
- Con: Learning curve
- Con: CLI focused
- Con: Newer tool
- Con: Limited features
- Con: Still maturing
Key features
Weights & Biases
Track, compare, and share ML experiments and models
The pricing for Weights & Biases is fair, offering a generous Free tier and a competitive Pro tier at $60/month.
Watch out
Overage fees for storage/Weave data on Free tier
Strengths
- Pro: Great visualizations
- Pro: Team collaboration
- Pro: Free tier
Weaknesses
- Con: Learning curve
- Con: Can be slow
Key features
Pricing: Promptfoo vs Weights & Biases
| Plan | Promptfoo | Weights & Biases |
|---|---|---|
| Tier 1 | Free Free | Free Free |
| Tier 2 | $50 month Cloud | $60 Pro |
| Tier 3 | custom Enterprise | Free Academic |
| Tier 4 | N/A | Custom Enterprise |
Pricing verified from each vendor's public pricing page. Compare in detail on Promptfoo pricing and Weights & Biases pricing.
Key Takeaways
Weights & Biases
- Free tier available
- Our pick for this comparison
Promptfoo
- Better fit for security
The Bottom Line
Weights & Biases wins this matchup.
Frequently Asked Questions
Is Promptfoo or Weights & Biases better in 2026?
Weights & Biases wins this matchup. Pick Promptfoo for security workflows (main strength: LLM eval framework). Pick Weights & Biases for analytics workflows (main strength: great visualizations).
What are Promptfoo and Weights & Biases used for?
Promptfoo: Build secure AI applications with AI security testing integrated into your development workflow. Weights & Biases: Track, compare, and share ML experiments and models.
What does Promptfoo cost vs Weights & Biases?
Promptfoo's paid plans start at Free (Cloud). Weights & Biases's paid plans start at Free (Pro).
What's the main difference between Promptfoo and Weights & Biases?
Promptfoo's main strength: LLM eval framework. Weights & Biases's main strength: great visualizations.