Navigation Product How it works Pricing Docs Open PromptLab →
v1.9 · Create · Library · Evaluate

Turn rough prompts into reusable, tested workflows.

Prompt Lab gives you one focused place to shape a draft, keep the version that works, and compare results when the work needs proof.

Free editor Local library storage Connect a provider when ready

One rough prompt, three strategies.

This transparent sample uses fixed example content. It never reads or sends your text.

Preview the three strategies on the same rough prompt
Sample result

Shape it. Save it. Prove it.

One repeatable loop keeps prompt work from disappearing into chat history: improve the instruction, save the useful version, and compare outcomes when quality matters.

Create

Sharpen drafts without losing the point

  • Choose a task type and destination, then Expanded, Refined or Rebuilt
  • Ask for alternatives to see all three strategies side by side
  • Every result shows a diff, its assumptions, and edits you can revert
  • Prompt scoring and lint checks surface weak spots early
Library

Keep and import the prompts worth reusing

  • Import preset packs, library exports, starter bundles and raw prompt arrays
  • Full-text search across your entire library
  • Compose longer prompts from saved fragments
  • Scratch notes stay beside the editor, out of your saved versions
Evaluate

Review runs instead of guessing

  • Run timeline with provider, model, latency and status
  • Diff of every improvement on every plan; Compare in Pro
  • Extension and desktop support Claude, OpenAI, Gemini, OpenRouter and Ollama
  • The browser extension keeps the workbench beside ChatGPT, Claude and other AI tools

Local by default. Checked before it’s sent.

The editor keeps prompts and libraries in local browser storage. Before a prompt goes to a provider, Prompt Lab scans it and offers to redact what it finds.

  • Local by defaultDrafts and saved library items remain in this browser unless you export or connect another service.
  • Provider choiceA provider receives content only when you connect it and run a provider-backed action.
  • Exportable workKeep reusable prompts portable with library import and JSON export.
Read the privacy policy →

What the check looks for

  • Email addresses
  • Phone numbers
  • US Social Security numbers
  • Payment card numbers
  • IPv4 addresses
  • API keys
  • Bearer tokens
  • Passwords and secrets
Example, redacted before send2 found

Summarise this support thread from [EMAIL]. The webhook fails with Authorization: Bearer [BEARER_TOKEN]

The check is pattern-based. It does not recognise names, street addresses or other free-text personal details, so review those yourself.

Start free. Upgrade when useful.

The editor is free to use. Pro unlocks the comparison and organization tools that matter when prompt work becomes a repeatable practice.

Choose a Pro billing period
Free
$0
Free account
  • Expanded, Refined and Rebuilt strategies
  • Diff of every improvement
  • Sensitive data check before send
  • Prompt library with search
  • Preset pack and library import
  • JSON library export
  • Composer for saved prompt blocks
  • Extension setup guide
  • Local browser storage
Get started free

Know what happens before you open the app.

Do I need an account?

The hosted web app currently asks you to sign in. This landing-page sample does not, and it never sends example content to a provider.

What does the sensitive data check catch?

Email addresses, phone numbers, US Social Security numbers, payment card numbers, IPv4 addresses, API keys, Bearer tokens, and password or secret assignments. It is pattern-based, so it does not detect names, street addresses or other free-text personal details.

Are AI provider costs included in Pro?

No. Provider usage is separate from Prompt Lab Pro and remains subject to the provider account or local model you choose.

Where are my prompts stored?

The web editor keeps prompts and libraries in local browser storage. A provider receives content only when you intentionally connect it and run a provider-backed action.

Where are provider API keys stored?

Configured keys stay in browser or extension storage. Hosted web requests pass through Prompt Lab's domain-allowlisted proxy for browser compatibility, but the keys are not persisted server-side.

How do I cancel Pro?

In Prompt Lab, open Settings → Manage Billing → Manage Purchases to reach Stripe's customer portal, where you can manage or cancel the subscription.

Will choosing Pro charge me immediately?

No. The pricing choice opens Prompt Lab with your monthly or annual preference. You still review and confirm the billing flow inside the app.

Is there a desktop installer?

The repository includes desktop source and build notes. This page does not claim a packaged installer; use the web app unless you specifically want to build the desktop surface.

Build a prompt workflow,
not a prompt pile.

Open Prompt Lab on the web, install the extension when you want it beside the page, and keep a library that can move with you.

Try PromptLab free