Catch prompt regressions
before your users do.

Build regression test suites for your prompts. Compare outputs across versions. Block bad releases automatically.

Evaluation Results
v12 → v13
Regression detected

Before

84%

After

71%

−13%
50 test cases8 failed

"How do I reset my password?"

Missing password reset link in response

Works with your favorite LLM providers

OpenAI
Anthropic
Google AI
Features

Everything you need to ship prompts safely

A purpose-built toolkit for teams who need prompt QA they can trust.

Regression Suites

Build test datasets with expected outputs. Run them on every prompt change to catch regressions before they ship.

Quality Scoring

Set pass/fail thresholds for your evals. Block releases that don't meet your quality bar automatically.

Prompt & Output Diff

See exactly what changed between prompt versions. Visual diffs show where outputs broke and why.

Model Matrix

Test the same prompt across OpenAI, Anthropic, and Google side-by-side. Find the best model for your use case.

Shareable Reports

Generate links for PRs, Slack, or stakeholder reviews. Everyone can see test results without an account.

BYOK + Secure Storage

Bring your own API keys. They're encrypted at rest, never logged, and stay under your control.

How it works

From setup to quality gate in minutes

No complex configuration. No steep learning curve. Just reliable prompt QA.

1

Create a regression suite

Start a project and define your test scenarios. Group related prompts, models, and test cases together.

2

Add test cases

Build your eval set with FAQs, edge cases, and expected outputs. Import from JSON or create directly in the app.

3

Run on every prompt version

Test each prompt change against your full dataset. Compare outputs side-by-side across models.

4

Set a quality gate

Define pass/fail thresholds. Block releases that regress below your quality bar.

5

Share the report in PRs

Generate shareable links for code reviews. Stakeholders see results without needing an account.

Bring your own API keys (encrypted)
We don't train on your data
Share reports without accounts
Pricing

Simple, transparent pricing

Start free, upgrade when you need more.

Free

$0

Best for trying out PromptLens

  • 1 project
  • 10 prompts
  • Quick testing (10 test cases)
  • All LLM providers
Get started
Recommended

Pro

$99/month

For teams shipping LLM features

  • 10 projects
  • Unlimited prompts
  • Comprehensive testing
  • Email support
Start testing free
FAQ

Frequently asked questions

Everything you need to know about PromptLens.

How is this different from writing unit tests?

Unit tests check if code runs correctly. PromptLens checks if LLM outputs are actually good. You define expected behaviors, and we evaluate whether prompt changes maintain or improve output quality across your entire test suite.

How long does setup take?

Most teams run their first evaluation within 5 minutes. Create a project, add a few test cases, and run your prompt against them. No complex configuration or infrastructure required.

Does it work with my LLM provider?

Yes. PromptLens supports OpenAI, Anthropic, Google AI, and any OpenAI-compatible API. Bring your own API keys—they're encrypted and never logged.

Is my data secure?

Your API keys are encrypted at rest and never logged. We don't train on your data or store outputs longer than needed for your evaluations. You maintain full control over your prompts and test cases.

Can I test across multiple models?

Yes. Run the same prompt and test cases across different models side-by-side. Compare GPT-4 vs Claude vs Gemini to find the best model for your specific use case.

Do I need to change my existing workflow?

No. PromptLens fits into your existing process. Generate shareable report links for PRs, Slack, or stakeholder reviews. No one needs an account to view results.

Stop shipping broken prompts

Run your first evaluation in under 5 minutes. Catch regressions before they reach production.

No credit card required • Set up in 5 minutes