Manual testing: Everything you need to know

In this post, we’ll look at what manual testing is, its benefits, its drawbacks, and how it compares with and complements automated tests.

Say you’re testing a checkout flow for a shopping app when you notice that the payment button hides behind the keyboard. It works perfectly in code, but users would struggle to tap it. This is manual testing’s strength: catching the issues automation misses.

In this post, we’ll look at what manual testing is, its benefits, its drawbacks, and how it compares with and complements automated tests.

Manual testing is the process where testers execute test cases manually without the assistance of automation tools

What is manual testing?

Manual testing is the only form of testing where the tool is a human being, and that’s exactly why it still matters.

As IBM defines it, “Manual testing is the process where testers execute test cases manually without the assistance of automation tools.”

In simpler terms, that means testers go through the software by hand. They click buttons, fill out forms, and try to break things. They’re looking for bugs, sure, but also checking if the flow makes sense for users.

How did this all start?

Manual testing’s been around since the 1940s. Back then, programmers would mostly test their code by debugging (as noted by IBM’s “History of software testing”) until proper test cases and structured methods began emerging in the 1980s.

By that time, testing became its own discipline, focused on ensuring quality instead of just fixing bugs.

After that, automation was introduced in the 1990s, and finally, we could let machines handle repetitive checks while testers focused on user experience and complex workflows.

Characteristics of manual testing

Here are the key features of manual testing that make it unique.

1. It’s driven by observation

In manual testing, testers use the product, and from this, they observe what is wrong, like confusing flows or layouts that affect users, which automated tests would typically miss.

2. It’s flexible and unscripted

Since there’s no fixed path, testers can explore, change direction, and follow new ideas as they test. And when requirements change, they can adjust instantly without rewriting anything.

3. It depends on human judgment

Since testers are humans, they bring their own unique perspective. One might see a serious issue, another might not. This variety adds depth, even if it sometimes creates inconsistency.

4. It requires understanding real users

Manual testing works best when testers think and act as a normal user would. They try to figure out what would happen if someone got stuck or what would frustrate them. This kind of insight goes beyond scripts.

5. It’s not repeatable in the exact same way as automation is

One key theme of manual testing is inconsistency, which makes your testing results vary on every run. Even something like your state of mind while doing the tests can make you see and report something different from another tester.

Why is manual testing important?

People often call manual testing old-fashioned, but it’s still one of the most practical ways to find issues and catch edge cases that tools could miss, plus it also helps teams see the product the way users experience it. Here’s why it is important:

1. Leaves room for human judgment

Manual testing leaves more space for human judgment and observation. A tester can easily notice small things like clicking a button while it’s still loading, or when the onboarding flow is confusing for first-time users, both situations that automation mostly won’t cover.

2. Easily adapts to changing requirements

Manual testers don’t need scripts, so they can quickly adapt when requirements shift. A new feature dropped? They jump in and explore the flow to find issues. This makes manual testing invaluable for MVPs and fast-paced projects where everything’s still evolving.

3. Tests real user behavior

Manual testing lets you explore actual user patterns, not just ideal scenarios. Take a payment page, for example, where users can sometimes get distracted. They might fill in their card details, then answer a phone call, and then return 15 minutes later to submit.

Does their session expire for security reasons? Or worse, does it still allow them to submit after such a long time? These unexpected situations are rarely covered in automated test scripts.

4. Catches UI and usability issues

Manual testers notice when things seem wrong, like when buttons are too close together, text overlaps, or popups block your clicks.

If a payment button gets covered by the keyboard, automation would still pass the test because it only checks if the button works in code, not how it looks or behaves on a real device. But in manual testing, you’d spot right away that users can’t even tap the button.

Automation tells you if the button works. Manual testing tells you if anyone can find it.

5. Works better for complex interactions

Dragging, dropping, resizing, and scrolling through nested menus are painful interactions to automate. Manual testing works better here because you immediately notice when something’s clunky. If there’s a slight lag or awkward gesture, you can catch it instantly while using it.

Manual testing complements other testing approaches rather than replacing them

6. Where does manual testing fit into the broader testing strategy?

Manual testing complements other testing approaches rather than replacing them. Teams typically run automated tests with each code deployment to catch bugs quickly.

However, before major releases, manual testers review the application to verify end-to-end workflows and examine things that automation often overlooks (such as text alignment issues, color contrast, performance lag, and navigation flow).

This becomes valuable during UAT (user acceptance testing), where human evaluation matters. Overall, the automated and manual combination ensures that both technical accuracy and practical usability are addressed before the software reaches end users.

An application can pass every test and still ship a bad experience. That gap is where manual testing lives.

Why perform manual testing on real devices?

Remember the payment button that hides behind the keyboard in the example we saw earlier? How could a tester catch that without using a real device? These incidents, and many others, are why manual testing on a real device is crucial. Let’s take a look.

1. Testing performance on real devices

Running heavy animations and gestures on your emulator could give misleading performance results, as it uses your laptop’s resources. But your users with mid-range Android phones would experience something laggy on their devices.

2. Testing under an unstable network

Users deal with weak signals, slow Wi-Fi, and network switches/interruptions, and you can’t reliably test how your app would react to these problems with an emulator.

3. Testing hardware interruptions

Calls, notifications, low battery, or sudden rotation can break your app. With real devices, you can see how your app handles these everyday interruptions.

4. Validating hardware features

Things like GPS, camera, fingerprint pads, and other sensors don’t work properly on emulators. You need physical devices to test them properly.

5. Testing app behavior across devices

Because on native devices like Android, manufacturers can customize the OS and how it feels, which could change how your apps run on these platforms. You need to test across different devices to catch device-specific issues.

Types of manual testing

Manual testing comes in many forms; some are planned, some are instinctive, and they often overlap. For instance, you might do exploratory testing during UAT or run test cases in an end-to-end flow.

1. Manual test case execution

In this testing approach, you work through a written checklist of steps and inputs, then compare results against expectations.

For example, when testing a login form, you try incorrect credentials, wrong passwords, or invalid emails.

Then, you check if error messages show up properly and also click the Forgot Password link to confirm that it works. It’s a straightforward, methodical test that follows a plan.

2. Exploratory testing

Here, you test with just your curiosity, trying different paths to see what happens. You might type some special characters into a search bar or open five tabs at once and identify if the app freezes or if any other unexpected issue occurs.

Usability testing checks how easy and natural the app feels for users.

3. Usability testing

Usability testing checks how easy and natural the app feels for users. Testers might move through the onboarding flow, for example, and if they can’t easily find the Next button, something’s wrong, and they will report it.

4. End-to-end testing

In end-to-end testing, you test like a real user, going through the whole flow from start to finish. For example, in an online store, you might add items to the cart, apply a coupon, pay, and check if the confirmation email arrives. Everything should connect smoothly.

5. Regression testing

In fast-moving projects or early stages where automation scripts aren’t stable yet, regression testing is often done manually to quickly check that existing features haven’t broken after an update or bug fixes.

For example, a dashboard update might stop your notifications from showing because the new code overwrote a shared function or altered the data-loading mechanism.

6. Ad-hoc testing

Ad-hoc testing is more random and based on instinct. For instance, while testing a food delivery app, a tester might add the same meal three times, then remove one after applying a coupon (something mostly unexpected). Actions like this often show subtle bugs that most formal tests might not cover.

7. Compatibility testing

Here, you’re checking if your app works everywhere users might use it. A page might look perfect in Chrome, but doesn’t load in Safari because of how Safari processes cookies. With compatibility testing, you test everywhere to catch these inconsistencies.

8. User acceptance testing (UAT)

In UAT testing, users or clients test the app to see if it meets their needs. Although it’s manual, its focus is on the business value, not bugs.

A manager might test an expense system by submitting a claim and checking if it shows up in his reports. It’s done before release to confirm that the system works for the people who’ll use it.

Skills required for manual testing

To accomplish a reliable manual test, you need certain skills, including:

1. Analytical thinking

This is one of the most important skills in manual testing because it helps you go beyond basic checks and really understand how a feature can break.

You don’t just test features, you try to break them in your head. On a login page, for example, you think about wrong inputs, empty fields, spam clicking, and even expired sessions.

2. Attention to detail

Another key skill you need for manual testing is having an eye for the slightest of details, especially those relating to critical user flows.

3. Domain knowledge

You also need to understand what you’re testing and the industry. For example, a banking app is not the same as an e-commerce app, and you have to look out for different things.

While one deals with transfers and savings, the other deals with carts, discounts, and checkout. If you don’t understand the domain, you miss real user issues.

4. Communication skills

As a tester, communicating is everything. If you can’t report your bug clearly, all your work will be a total waste of time, and at the end of the day, it will most likely not be fixed or be deprioritized.

5. Understanding the development process

You also need to know where testing fits in the whole development process. When to test, what starts it, and how your work affects others. It helps you stay in sync with the team and not slow down the work.

6. Test case writing

Although you don’t need to code, you should be able to write simple test cases that others can follow, which help guide testing.

7. Curiosity and break-it mindset

Good testers are naturally curious. They don’t just follow instructions; they try different inputs and unexpected actions just to see what breaks.

How to perform manual testing

Now we have the foundation skills down. Next, we’ll break down the steps you need to consistently track down bugs.

Step 1: Understand the requirements

Before you begin, digest any existing documentation to understand the application. A vast proportion of defects testers miss comes from not fully grasping what the feature is supposed to do.

Step 2: Make a test plan

Here’s when you map out what will get tested, what you will ignore, who will test what, plus an estimated time of delivery. Skipping this now can cause friction down the road.

Step 3: Write test cases

Write simple and clear test cases that someone else can follow. Something clear will cut out unnecessary back-and-forth questions.

Step 4: Set up the testing environment

Next, get your testing devices and your browsers ready, especially those used by the majority of your users.

Step 5: Execute the test

Now you can run the tests, carefully compare what happens against what should happen, and document everything.

Step 6: Log defects

Document defects so they can be fixed. Be very specific for each issue, too. Include your title, steps to reproduce, environment details, screenshots, and severity. Vague reports like “login broken” make it hard for developers and delay fixes.

Step 7: Verify fixes and check for regression

Don’t assume a fix worked; retest it. And don’t assume the fix didn’t break something else; be sure to run regression tests on connected features.

Step 8: Summarize results

Finally, summarise your report on the test. It should cover your code coverage, defects, quality, and lessons learned to make your next cycle less stressful.

Tools used for manual testing

To reliably do your manual tests, some tools can help keep you organized and get reliable results. These tools include:

Test management tools

Once you’re handling many tests, it’s easy to lose track. Tools help you stay organized. Tricentis qTest lets you create, manage, and run tests in one place, while also using AI to detect repeated steps and reduce duplicate tests.

You log what’s broken and assign a developer to work on the fix.

Bug tracking tools

Tools like GitHub Issues are there to organize your bug-tracking process. You log what’s broken and assign a developer to work on the fix. You can add comments, share updates, and clearly see what is still open, in progress, or already fixed.

Screen capture and recording tools

These tools help you present bugs visually to developers, which makes it easier to fix. With Loom, you can record a quick screen video showing exactly what broke, and Snagit lets you put arrows and notes on your screen record.

Browser dev tools

Chrome DevTools allow you to inspect your web application with just a click, so you can check UI elements, view console errors, and monitor network requests, giving you a proper understanding of the issue.

Real-device cloud platforms

Instead of managing multiple physical phones, you get access to real devices on demand with device cloud platforms. This provides you with different devices and OS, helping you test across these different environments.

Manual testing vs. automated testing

Manual and automated testing both aim to find bugs and make software reliable, but they do it in very different ways. Here is how they compare:

When to use manual testing

1. Use manual testing when you’re expecting a lot of changes in the application. It’s easier to adjust and test things by hand instead of updating scripts all the time.
2. It works best for ad-hoc or exploratory testing, where you’re just trying different things to see what breaks.
3. Also, if it’s a small project like a demo app, or there’s not much time or resources for automation, go for manual testing.

When to use automation testing

1. Go for automation when the same tests need to be run again and again, like regression or smoke tests. Once you set it up, it saves a lot of time.
2. It’s perfect for big projects with many features, since testing everything by hand would be time-consuming.
3. If you need quick feedback from your tests, go for automation.

In manual testing, testers can adapt easily when features or requirements change

Benefits of manual testing

Manual testing is flexible and helps catch issues that tools can’t easily spot. Here are some key benefits:

1. Finds user interface (UI), user experience (UX), and usability bugs that automation might miss.
2. In manual testing, testers can adapt easily when features or requirements change.
3. It has a lower setup cost, as there is no need for tools or test scripts.
4. It’s great for exploratory or ad-hoc testing where scenarios aren’t predefined.
5. It helps improve test coverage when combined with automated tests to find subtle bugs.

Drawbacks of manual testing

Manual testing is useful, but it also has some downsides you should know about. It can be slow, tiring, and sometimes less consistent. Here are some common drawbacks:

1. Different testers may interpret requirements or UI differently. So what one tester sees as a Pass, another may see as a Fail.
2. It’s prone to human error because, as testers get tired, they may miss details, skip steps, or misinterpret requirements.
3. It’s repetitive and becomes boring. Doing the same tests over and over is monotonous, which increases the chances of mistakes or oversight.
4. Running tests by hand for each scenario takes a lot of time, especially in a big project with many features.
5. Sure, manual testing costs less upfront, but if you keep doing it release after release on a large application, it ends up being expensive, costing you a lot of time and money.

Manual testing best practices

Here are some key practices that make manual testing reliable and efficient:

1. Always read and understand the product requirements and user stories, if available.
2. Link test cases to requirements to avoid repetitive or missing tests for important features.
3. Prioritize your testing. Your login flow, payment flow, or any other integral flow should always come first.
4. Ensure someone else reviews your test cases before you run them, because you might miss something or skip some edge cases.
5. Your bug reports should be specific—with reproduction steps, environment details, and a screenshot if possible.
6. Run regression tests after every fix to ensure everything else still works fine.
7. Keep updating your test cases, especially when there are changes to the product requirements.

How agentic AI is augmenting manual testing

With the rise of AI and agentic AI now, teams are figuring out how to use it to support testers and make things faster. Here’s how that looks.

1. Faster test case creation

Agentic AI tools can turn requirements into test cases in minutes. What used to take 30 to 60 minutes per ticket can now take under 2 minutes.

2. Test creation from natural language

With agentic AI, you can type something like “create a sales order for customer 1175,” and the system builds a full test case. This helps new tests get started faster and reduces manual effort.

3. Smarter test selection

Agentic systems can analyze your code changes and past bugs to decide what to test first. So that instead of running 200 regression tests, it can suggest the 5-10 that truly matter based on your recent changes.

4. Self-healing tests

With an agentic system, your tests can adjust when UI elements change, like a button moving or a label updating. This reduces time spent fixing broken tests.

Agentic testing handles the repetitive tasks, so human testers can focus on what requires human judgment.

How Tricentis supports agentic testing

At Transform 2025, Tricentis CEO Kevin Thompson dropped a stat worth sitting with: “Over 40% of code written last year was generated by AI.”

That doesn’t make testing easier. More code produced faster means more edge cases, more integration risks, and more gaps that manual testers simply can’t cover at scale.

Tricentis uses agentic quality intelligence to close the testing gaps that this speed and scale create.

Tricentis Tosca handles end-to-end test automation, SeaLights maps code changes to coverage in real time, qTest manages test planning and results across the team, and NeoLoad confirms systems performance holds up under real traffic.

Together, they cover the full testing life cycle and cut down the manual work of stitching everything together across teams.

Use case: How VodafoneZiggo cut testing time by 90% and saved 75% on performance costs with Tricentis

VodafoneZiggo runs telecom services across 200+ connected systems in the Netherlands. Testing was slow, manual, and expensive. Here’s what they did.

Problem

Manual testing was slowing down releases, and the automation attempts with Selenium failed. Also, their test plans lived in Excel, and their performance testing was outsourced and costly.

Solution

They brought in Tosca for automation, qTest to replace Excel, and NeoLoad to handle performance testing internally.

Outcome

Here’s what changed:

• Automation runs became 90% faster.
• Performance testing costs dropped by 75%.
• 400+ test scenarios automated across 15+ applications.
• 4500 webpages accessibility-tested in under two hours.

Conclusion

Automation handles a lot and does it quickly, but it doesn’t think like an actual person using your software. Human testers spot things that look off or awkward.

They catch usability issues that automation completely misses, like confusing layouts, slow responses, or unexpected user behavior.

The next evolution of this balance is agentic testing, where AI handles repetitive tasks in a smarter way, so testers can focus on things that need human judgment.

That’s where Tricentis comes in. As a leading agentic testing platform, Tricentis bridges the gap between manual and automated testing. It helps teams balance speed and quality better. You can move fast and still build something reliable for people.

Ready to see agentic testing in practice? Explore Tricentis agentic testing tools.