How to block a deploy when signup or checkout breaks

As a solo founder, you are the builder, the marketer, the support team, and the QA team.

Most founders ignore the last one.

That’s risky.

A small change can break:

Signup
Checkout
Login
Payment
Booking
Upgrade

You might not notice right away.

And if a payment or signup flow breaks in production, you lose money.

The solution

Instead of manually clicking around before every deploy, you can build a small browser QA agent that checks your most important flows automatically.

We’ll build a signup funnel as an example.

But this works for any critical flow.

What this QA Agent does

It goes through your site step by step.

It:

Opens the site
Clicks what users click
Fills what users fill
Submits forms
Checks that it worked
Stops if it didn’t
Save screenshots and logs of what happened

You run it before you deployment.

If it fails, you fix the issue first.

What tools you need

Use a browser automation tool.

For example:

Playwright
Puppeteer
Cypress
Or any no-code browser tester

Make sure it can:

Open a real browser (Chrome, Chromium, etc.)
Click elements
Fill input fields
Wait for pages to load
Take screenshots
Read the current URL
Check if text exists on the page
Capture console errors
Capture failed network requests

If it cannot check results and fail the test, it is not real QA.

Optional: You may also use an AI model for summarizing logs.

That’s all you need.

Step 1 — Pick one critical path

Choose one key user journey.

Something that would hurt if it were to break.

Examples:

Signup
Checkout
Login
Upgrade

Give it a simple name.

Example: Login QA

Step 2 — Add the user steps

Open your browser tool and create a test.

Now, add the same steps a real user takes:

Open your website
Wait for the page to load
Take a full-page screenshot
Click the main CTA
Wait for the next page to load
Take another screenshot
Enter email (use a new one for each test run )
Enter password
Click Submit
Wait for success condition
Take a final screenshot

Now it behaves like a user.

Next, we add checks.

Step 3 — Add PASS / FAIL rules

After the Submit step, add checks.

In most tools, you do this by:

Clicking “Add Step”
Choosing: Assert, Check, Verify, Validate, or Condition

Now add two checks.

Check 1 — URL Check

Add a rule: Current URL contains /welcome

If not:

Mark test as FAIL
Stop test immediately

Most tools have a setting like:

Stop on failure
Abort on error
Fail fast

Turn that on.

Check 2 — Success text check

Add another check.

Rule: Page contains text “Welcome” or “Account created”

If not:

Fail the test
Stop the test

One check is not enough. The page can load, but still fail.

Step 4 — Fail on errors

Now make sure the test fails if there are hidden errors.

First, turn on logging.

In your tool’s settings, enable:

Console logs
Network logs
Failed requests
Error tracking

These are usually found in:

Test settings
Advanced settings
Execution settings
Debug options

Turn them on.

Now decide how errors should behave.

If your tool has options like:

“Fail on console error”
“Fail on network error”

Turn them on.

You’re done.

If your tool does NOT have automatic failure:

Add one more check at the end of your test.
Add a new Assert / Check step.

Create these two rules:

Failed request count = 0
Console error count = 0

If either number is greater than 0 → FAIL the test.

Step 5 — Configure failure behavior

Open test settings (every tool has a version of this).

Turn on these three things:

Stop on first failure
Screenshot on failure
Save logs on failure

If your tool doesn’t have “screenshot on failure”, you fake it by adding:

A screenshot step right before each check
Another screenshot step right after each check

Every failure should leave proof.

Step 6 — Save every run

You need a place to store the results of each test run.

Create a folder called: qa-runs

Where you create it depends on how you run your tests (the folder should live in the same place your test executes):

If you run tests on your computer → create it in your project folder
If you use CI → create it in the project root
If you use a no-code tool → use its Artifacts or Downloads section

Each test run should save:

Screenshots
Console logs
Network logs
Test result (PASS or FAIL)

If your tool allows it, save each run in its own subfolder using a timestamp.

Now you can review history.

Step 7 — (Optional) Use AI to read the logs

Use this when:

Logs are long
There are many warnings
You want severity classification
You are not deeply technical

You can paste logs and results into your AI model of choice and ask it to:

Classify issues (Critical / Major / Minor)
Identify business impact
Suggest next steps

This saves you from manually scanning raw logs.

If you’re technical and your logs are clean, you can skip this step.

Step 8 — Run it before every deploy

This is the most important part.

Change your process from: Code → Deploy

To: Code → Run QA → Deploy

You can connect it to:

GitHub Actions
Any CI system
Your hosting build step
Or a manual deploy script

In all cases: If QA fails → do not deploy.

No exceptions.