Prompts change.
Quality shouldn't.

PromptLens helps teams test prompt changes, compare outputs, and prevent regressions before users see them.

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

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
Start free
Recommended

Pro

$29/month

For devs shipping LLM features

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

Team Plan — Coming Soon

Shared workspaces, admin controls, and dedicated support for production teams.

Join the waitlist

Ready to ship prompts safely?

Test prompt changes, compare outputs, and prevent regressions before your users see them.

No credit card required • Free plan available