How an Agency Could Catch a Checkout Bug Before It Costs a Client $50K

For Shopify agencies, every missed bug is a potential crisis — not just for the client’s bottom line, but for the agency’s reputation. This is a hypothetical scenario, not a customer case study. It walks through how an agency could turn a near-disaster into a retention win with proactive QA and automation.

The scenario

Imagine an established Shopify Plus brand launching a flash promotion. A last-minute theme update introduces a small JavaScript conflict that breaks the mobile checkout button on certain devices. Conversion starts falling, but the store still loads, so nothing looks wrong at a glance.

Now imagine the agency managing the store gets an alert shortly after the deployment, before the client even knows something is wrong.

The catch

In this scenario the agency runs scheduled Shoptest journeys that cover cart and checkout on desktop and mobile. When the mobile checkout test fails, Shoptest sends an alert with screenshots and logs to the agency’s Slack channel.

The team diagnoses the conflict, ships a fix and re-runs the test to confirm checkout works again, ideally before the client starts their day.

What is at stake

During a flash promotion, a broken mobile checkout can cost a large store tens of thousands in a single day. For a store at that scale, losses in the region of $50,000 are plausible if the problem runs unnoticed for long enough. Catching it early changes the outcome:

• Less revenue lost during the promotion

• A client who hears about the problem from the agency, with a fix already in place, instead of from customers

• A stronger case for keeping monitoring in the retainer

The lesson for other agencies

This wasn’t just about saving money — it was about preventing escalation and preserving client confidence. When agencies catch issues before the client or end-customer experiences them, they not only protect revenue but also elevate the perception of their service. They become proactive partners, not just vendors. This shift repositions QA from being a back-office technical cost to a strategic, high-impact differentiator that directly contributes to client retention and long-term value.

How Shoptest makes this possible

What would let an agency catch a bug like this quickly? Continuous monitoring built into its QA workflow. Here is what Shoptest gives an agency team:

• Run tests on key store flows automatically and frequently

• Catch broken journeys early, not after customer complaints

• Get alerts by Slack, email or webhook, with screenshots and logs

• Prove your agency’s value with client-ready monitoring reports and run history

Final thoughts

In high-velocity eCommerce environments, mistakes happen — but they don’t have to become disasters. Agencies that arm themselves with proactive QA tools like Shoptest are better equipped to deliver stability, trust, and long-term growth for their clients.

Related reading: testing your checkout flow after every theme update, reducing client complaints with automated QA and using monitoring reports to justify a retainer.

Want to protect your clients this way? See Shoptest for agencies →