What is automated testing?

utomated testing means software runs your tests instead of a person. Scripts execute predefined steps, check the results, and report pass or fail, all without human involvement. It handles repetitive regression checks faster and more consistently than manual testing, but it isn't a replacement for it: each approach handles different problems well.

At a glance

• Automated testing uses scripts to run checks without human involvement, so it's fast and consistent for repetitive scenarios
• It doesn't replace manual testing: automation only finds problems you anticipated, humans find the rest
• Automate when the time investment pays back: regression checks you run many times, cross-browser checks, stable API flows
• Manual testing is the better choice for new features, exploratory work, and visual or usability judgment
• Start small: automate one test you repeat often before building a full suite

The rest of this post covers how automated testing works, how it compares with manual testing, and when each one is worth using.

How does automated testing work?

Automated testing runs pre-written test scripts that interact with your software and check the results.

Here's a typical automated test in action:

1. Setup: The script launches your application and sets up any necessary test data
2. Execute: It performs specific actions – clicking buttons, entering text, navigating pages
3. Verify: It checks if the actual results match what you expected
4. Report: It logs what passed, what failed, and any errors encountered

Take a login test as an example. An automated script might open your login page, enter a username and password, click submit, then verify the user lands on the dashboard. Run that script, and you'll know within seconds if login still works. Run it across ten different browsers simultaneously, and you've just saved hours of checking.

The script executes the exact same steps every time. That consistency means it catches regressions reliably, but it also means the test only checks what you explicitly told it to check.

Automated testing vs manual testing: what's the difference?

The difference between automated testing and manual testing comes down to execution. Manual testing relies on human testers clicking, typing, and observing. Automated testing uses scripts to do the same work without human involvement.

Each approach has distinct strengths:

Automated tests will never notice that surprising edge case a manual tester might stumble across. But manual testers can't match automation's speed for repetitive regression checks. DORA's research points out that manual regression testing is slow and expensive enough to become a bottleneck in delivery, and finds that teams whose developers create and maintain their own automated test suites deliver software better.

Most teams use both. The question is less automated vs manual testing and more about what approach fits which situation. We talk more about manual vs automated testing here if you’re interested.

When should you use automated testing?

Use automated testing for tests that run frequently, follow predictable patterns, and would be tedious to repeat manually. Automation needs significant upfront time investment: writing automated tests takes much longer than writing a manual checklist, and maintaining them as your software changes takes ongoing effort. It only pays off when you'll run those tests often enough to make back that investment. The best candidates for automation:

• Regression tests: When you fix a bug or add a feature, you need to know existing functionality still works. Automated regression tests catch problems efficiently, and they can run continuously during development so the release process keeps moving.

• Repetitive scenarios: If you're testing the same login flow, search function, or checkout process for the twentieth time, automation saves considerable effort.

• Cross-browser and cross-device testing: Manually testing on Chrome, Firefox, Safari, Edge, plus various mobile devices takes days. Automated testing runs these checks in parallel.

• Performance and load testing: Simulating thousands of concurrent users isn't feasible manually. Automation reveals how your system behaves under pressure.

• API testing: APIs need testing with numerous parameter combinations. Automated testing handles this more efficiently than making manual API calls.

• Data-driven tests: When you need to run the same test with multiple data sets – different user types, payment methods, or input variations – automation makes sense.

When should you use manual testing?

Manual testing works better for tests that change frequently, require human judgment, or involve exploration and discovery.

Choose manual testing for:

• New or unstable features: Features under active development change too quickly for automation. Manual testing provides faster feedback without the overhead of maintaining brittle scripts.

• Exploratory testing: Testing without a predetermined script lets you follow interesting paths as you discover them. If clicking a button produces an odd result, you can immediately investigate why – something automated tests can't do. This adaptability helps uncover problems you didn't know to look for.

• Visual and usability checks: Does the page look right? Does the workflow make sense? These subjective evaluations need human eyes and judgment.

• Complex user workflows: Some scenarios involve too many variables and decision points to script effectively. Manual testers can adapt as they go.

• One-off tests: If you'll only run a test once or twice, manual testing is faster than writing and maintaining automation.

• Initial verification: Before investing in automation, manually test new functionality to ensure it's stable and worth the automation effort.

A useful rule of thumb: if maintaining automated tests takes more effort than just running the tests manually, you're automating the wrong things.

What are the benefits of automated testing?

Automated testing saves time on repetitive tasks, gives faster feedback, and allows for more thorough coverage for regression checks. The main advantages of automated testing:

• Speed for repetitive checks: Automated tests run in minutes instead of hours or days. Computers can run tests 24 hours a day, seven days a week, transforming the scale at which testing operates. What takes a manual tester a week might finish overnight.

• Consistency: Scripts execute identically every time. No variation from tester fatigue, distraction, or forgetfulness. This reliability catches regressions systematically.

• Broader coverage for stable features: Automation lets you test scenarios that would be impractical manually – 50 different data combinations, 20 browser versions, overnight regression runs.

• Faster feedback on code changes: Automated tests integrated into your development pipeline give immediate feedback. Developers learn about problems within minutes, not days.

• Better resource allocation: Automation handles repetitive regression checks, freeing your testing team for exploratory testing, complex scenarios, and cases requiring human judgment.

• Cost efficiency over time: The upfront investment in automation tools and script development pays off when you run tests repeatedly.

What are the limitations of automated testing?

Automated testing solves specific problems well, but it has real limitations including:

• High upfront investment: Writing automated tests takes considerably longer than creating manual test scripts. You'll spend weeks or months building a test suite before seeing returns.

• Maintenance burden: Every time your software changes, your automated tests need updating. Features that change frequently means constant test maintenance.

• Can't evaluate user experience: Automated tests check if functionality works, but can't judge whether something feels right to use or if the interface makes sense. They miss unclear error messages, confusing workflows, and visual inconsistencies.

• Lacks human intuition: Automated tests only find problems you anticipated. They can't explore interesting paths, react to unexpected behavior, or spot the kinds of issues that make a tester say "that's weird."

• Technical skills required: Building and maintaining automated tests often needs some level of technical or even development expertise. Not everyone on your team can contribute.

The pragmatic approach to automated testing

Automated testing has its place, but it's only as effective as the time and money you put into setting it up – and it won't help you find the problems you didn't anticipate.

Our advice is to automate when it's cost-effective. Don't treat automation as the goal. Use it strategically where the time investment actually pays off, and keep manual testing as your primary tool for discovering the unexpected.

If you're going to automate, focus your efforts on:

• Core business functionality that absolutely can't break
• Tests you'll run dozens of times per release
• Checks requiring multiple configurations or large datasets
• Stable features that follow predictable patterns

This is the same reasoning behind Martin Fowler's test pyramid: write lots of cheap, low-level automated tests, and far fewer of the slow, brittle end-to-end kind that break every time the UI changes.

Start small. Pick one repetitive test and see if automation saves you time. Don't build an automation suite because you think you should – build one because the math makes sense.

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