Introduction

With your test cases authored and your Jira board set up, the next phase of the QA lifecycle shifts from planning to action. This is where the real detective work begins. Manual test execution is the process of running your designed test cases against a live application: observing actual behavior, comparing it to expected behavior, and documenting every discrepancy you find.

This reading explains what happens during manual execution, how two specific tools help you verify and isolate different types of defects, and what a professional bug ticket looks like once evidence is in hand.

Manual Execution: More Than Just Clicking Through

Manual execution is not random exploration. You are working through the test cases you already designed, following each step deliberately, and recording what the application actually does at each point. When behavior matches the expected result, the test passes. When it does not, you have found a defect, and your job shifts to proving it.

Exploratory testing sits alongside scripted execution as a complementary technique. While scripted testing follows a predetermined path, exploratory testing encourages you to investigate the application freely, using your judgment to probe areas that feel unstable or inconsistent. In a real-world engagement, experienced testers combine both approaches, following the plan while staying alert to anything unexpected.

You will run all of this directly inside your lab VM (Virtual Machine), the Linux environment where GreenLeaf Grocers is hosted locally and ready for you to test against. In the GreenLeaf Grocers checkout flow, two defects have been seeded into the application. Each one requires a different tool to verify and isolate properly.

Verifying UI Defects With BrowserStack

A UI (User Interface) bug is a visual or interactive problem that affects how an application appears or behaves on screen, for example, a layout issue that only surfaces on certain screen sizes. BrowserStack lets you test on real mobile devices to catch exactly these kinds of problems.

BrowserStack is a cloud-based device testing platform that gives you access to real mobile devices without needing physical hardware. This distinction matters: simulators and emulators approximate device behavior, but real devices reflect the actual rendering environment your end users experience. Running your checkout flow on a real mobile device through BrowserStack and capturing a screenshot of the overlapping buttons produces concrete, reproducible evidence that belongs in a professional defect report.

Isolating API Defects With Postman

An API (Application Programming Interface) bug is a failure in the communication layer between the application's front end and its back end. When certain inputs are submitted in GreenLeaf Grocers, the server may return an error response instead of a graceful message. Postman allows you to send direct requests to the server and inspect the raw response to understand exactly what went wrong, information that the browser interface alone does not always reveal.

Postman is an API testing tool that allows you to send direct HTTP (Hypertext Transfer Protocol) requests to a server and inspect the raw response, completely independent of the browser interface. By sending a targeted POST request to the promo code endpoint in Postman and capturing the 500 response, you isolate the failure at the API layer.

This is a critical skill: it separates a front-end display problem from a genuine back-end failure, and it gives developers the precise information they need to fix it.

Writing a Flawless Bug Ticket

Finding a defect is only half the job. Documenting it clearly is what makes it actionable. A well-formatted bug ticket in Jira includes:

• Summary : a concise, specific title describing the defect

• Steps to Reproduce : the exact sequence that triggers the issue

• Expected Result : what should have happened

• Actual Result : what actually happened

• Severity and Priority : how serious the defect is and how urgently it needs fixing

• Evidence : screenshots, screen recordings, or API response captures attached directly to the ticket

For the two defects in GreenLeaf Grocers, your BrowserStack screenshot and your Postman screenshot serve as the evidence. Attaching them directly to their respective Jira tickets transforms a verbal description into a verifiable, professional-grade defect report.

Conclusion

Manual execution, cross-device verification, and API isolation are three distinct but connected skills that define a well-rounded QA Tester. Together, they ensure that defects are not just noticed, but proven, documented, and ready for a development team to act on.