Know what a change did before it ships.

Install the Molar GitHub App and pick the scenarios that protect a change. When a pull request gets a Vercel preview deployment, Guard finds its URL, waits until it responds and runs those scenarios against it. With other hosts, pass the preview URL to the GitHub Action.

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Preview checkExample

Pull request01

Update checkout confirmation

pull/48 · 3 files changed

- status: pending+ status: confirmed+ receipt: attached

Preview browser02

preview.northstar.test

Three browser tests

Signup and verificationPassed

Invite a teammatePassed

Payment confirmationNeeds review

Result03

Trace attachedOne check needs review before merge.trace_48_checkoutExplore Trace

Check the changed app

Run selected journeys against the environment created for a pull request.

Open the changed step

Use the status, screenshot, and Trace link to see where the preview diverged.

Attach the result to review

Give reviewers the scenario status and available run files alongside the code change.

A preview test in practice

A pull request changes checkout. The run opens the preview, selects the plan, verifies the callback, and reports the order state.

Preview URL
Critical path scenario
Order and callback result

Release check resultIllustrative example

Pull requestcheckout copy updatepreview / pr-184

Payment completePayment confirmed

Guard checkPassedPayment and order confirmedtrace_91c · 3 steps

Browser path Payment callback Order state

Gate the paths that changed

Choose the journeys where a regression matters most, then add signup, checkout, or invitation coverage as the team learns.

Signup and login
Checkout and payment
Invites and webhooks

The branches behind the Pay buttonExample checks to include

Card declined

No paid order; show a useful retry.

Authentication required

Keep the order pending until authentication finishes.

Callback delayed

Do not grant access before confirmation.

Callback delivered twice

One payment should create one order.

Frequently asked questions

Have a specific workflow in mind?
Talk to us

Does Molar test every pull request automatically?

Once the GitHub App is installed and you’ve picked the scenarios, Guard checks each pull request that has a preview deployment. With the GitHub Action instead, pass the preview URL as base-url.

Can previews use Clones?

Supported workflows can pair a preview with available service clones.

What happens when a check fails?

The run records a failed or blocked outcome with the available status, screenshots, and Trace references.

Test a preview deployment.

Create a free workspace and describe the first flow to test. Or check a public page first, no account needed.

Get started free Check a public page

Free during the beta. No card.