Web site testing - Tools and best practices

Introduction - Why site testing is an investment, not a cost

One mistake in a contact form can cost a company dozens of potential customers a month. A page that takes more than 3 seconds to load loses up to half of its visitors before they can see the offer.

Baymard Institute research shows that 69.8% of users abandon shopping carts, and in 18% of cases the reason is technical errors or usability problems. Amazon estimates that every second of delay costs them $1.6 billion a year. These are numbers that may seem abstract - but they translate into real losses, including for smaller players.

Examples from life help to understand this. The owner of a small sporting goods store didn't know for a month that the contact form didn't work on phones. He lost about 40 potential orders before a customer brought the problem to his attention. It took 15 minutes to fix, but the cost of the error probably amounted to several thousand zlotys in lost revenue. This shows that the difference between detecting a glitch before publication and responding after the fact is not just the cost of the programmer - it's also the lost trust and opportunity for future purchases.

Systematic testing can suggest greater reliability of the site and bring tangible benefits: higher conversions, better positions in Google, fewer complaints and greater customer satisfaction. The cost of a programmer's hour rarely exceeds $200-300, while a single lost customer can generate revenue many times higher. In addition, early detection of a problem usually means simpler and cheaper repair.

In practice, it makes sense to think of testing as an investment that builds competitive advantage. A company that regularly tests performance, functionality and safety earns a reputation as a more reliable partner. This likely translates into lower claims handling costs and more stable revenues.

In this article, you'll find specific tools for testing site performance, functionality and security. I'll also show you how to create a testing process that will save you time and increase profits without committing a large budget.

Basics of website testing - What to test and when to test

You already know why you should test. Now it's time to move on to practice. You don't have to test everything right away - some elements are critical, others can wait. The key is to take a systematic approach and be aware of which areas have the greatest impact on the business. Prepare a priority list and focus first on the things that are most painful for users and conversions.

Key areas in need of testing

Forms are the heart of conversion. Contact, order, newsletter signup - one error can mean losing a customer. Check whether forms are sending data at all, whether confirmations are going to email, whether validation is working properly and whether error messages are understandable. Examples: payment rejected after entering a card number, no confirmation of newsletter signup (no double opt-in), or a file upload box blocking the order process. A customer who can't complete a purchase often simply leaves for a competitor.

Responsiveness determines the first impression. More than 60% of traffic can come from mobile devices. A site that displays poorly on a phone is like a store with the door closed. Test different resolutions and orientations - e.g. iPhone SE, mid-range Android, tablet - and click with your finger, not a mouse. Make sure menus don't disappear off-screen, that form fields are easy to fill in, and that interactive elements are the right touch size.

Loading speed affects everything - conversion, SEO and user satisfaction. Google emphasizes this, and users are impatient. Check first-view loading times, interaction latency and whether images are optimized. Common sources of problems include suboptimal images, external scripts (such as social widgets) and lack of caching. Even a 1-2 second difference can significantly change the abandonment rate.

Compatibility with browsers may seem like a small matter, but the differences can sometimes be costly. 5% of users in an older version of Safari or IE is not the same as 5% in Chrome - their behavior and expectations may differ. Test popular browser versions and key features (JS, CSS Grid/Flexbox, forms). Sometimes a simple CSS fallback solves a problem that is critical for a certain group of users.

Security is the foundation of trust. Lack of SSL, vulnerable plug-ins, an outdated CMS - any vulnerability can end in data leakage or downtime. Hackers don't just target big companies; small stores fall prey to attacks, too. Check certificates, updates, access rights, and basic SQL-i XSS-type tests. It's also a good idea to monitor logs and have an incident response plan.

Site lifecycle test schedule

Test everything twice before launching. It's better to delay the launch by a week than to fix bugs with the first users. Prepare a checklist and go through each point methodically: forms, payment process, SSL, responsiveness, backups. An end-to-end test involving real scenarios (e.g., purchase with coupon, return, account registration) is a good practice.

Check the working website regularly - preferably every month. System updates, browser changes, server crashes - problems pop up unexpectedly. A monthly review can include basic testing: uptime, forms testing, plugin updates and a quick performance audit. If you have a high volume of changes, consider more frequent reviews.

Do a quick test after each shift. Have you added a new product? Test the entire shopping cart and order process, check promotional prices and coupons. Changed the template? Test responsiveness and all visible components. Even minor modifications can cause big problems - for example, adding an analytics script can slow down the site, or a CSS conflict can hide CTA buttons. Short, targeted tests after each change will likely save a lot of time later.

Tools for automated performance testing

Manually checking each subpage quickly consumes time. Automation allows you to monitor performance systematically and react to dips before customers notice them. Modern tools don't just measure speed - they also indicate specific steps worth taking to realistically improve the user experience.

Google PageSpeed Insights and Core Web Vitals.

PageSpeed Insights is a starting point for any company. Free tool from Google, regularly updated and linked to search engine ranking signals. Just enter a site address to get a rating from 0 to 100 and a list of recommendations.

Not every suggestion is of equal importance. First, focus on Core Web Vitals - metrics that Google officially takes into account. Largest Contentful Paint (LCP) measures how long it takes for the main content to load; a high LCP may suggest heavy images or a slow server. First Input Delay (FID) determines how quickly a page responds to a user's first interaction, and Cumulative Layout Shift (CLS) shows whether elements "jump" during loading - this is particularly troublesome in forms or when finalizing purchases.

Red indicators indicate critical problems - fix them first. Orange notes can be put off if they require a lot of technical effort. Practical example: optimizing images (converting to WebP, enabling lazy-loading) will probably give a faster and more noticeable effect than rebuilding the entire CSS system.

Combine PageSpeed with Google Analytics and Search Console. Analytics will show speed reports in the context of real traffic - which pages are generating the most page views and conversions. Search Console, in turn, will indicate which sub-pages are having problems with Core Web Vitals. This combination of data allows you to prioritize work according to real business impact - for example, fix the product pages with the most traffic first.

GTmetrix and other speed analysis tools

GTmetrix offers deeper technical analysis than PageSpeed. Waterfall chart shows step by step which resources load the slowest - it could be an improperly configured server, too large images or an excessive number of plugins.

Pingdom and WebPageTest give similar results, but testing from different geographic locations can reveal differences. If the majority of your users are from Poland, test from European servers rather than US servers - the difference can be a few seconds and significantly affect conversions. Waterfall may also suggest DNS or TTL problems if delays are already appearing at the connection stage.

Automatic monitoring saves time and nerves. Set up weekly reports in GTmetrix or alerts in UptimeRobot. Getting an alert when a site slows down below a set threshold is much better than responding to a complaint call on Friday night. Example: an alert at LCP > 3s will allow you to react earlier and prevent conversion rate drops.

Interpreting waterfalls takes practice, but the basics are simple: red blocks are critical errors, yellow blocks are warnings, and long bars indicate slow items. Look first for the biggest "win" - resources that take the most load time, such as a huge hero image, a heavy font or an external ad script. In practice, it is often enough to optimize 1-2 of the largest files to get a significant improvement.

Responsiveness testing tools

Responsinator shows the page on 15 popular resolutions simultaneously. It's a quick way to detect obvious layout problems. BrowserStack goes further - it allows you to test on real devices and operating systems through a browser, which can reveal minor bugs that emulators won't show.

Emulators in Chrome or Firefox developer tools are convenient for everyday use, but they are no substitute for testing on physical devices. A finger touch works differently than a mouse click, and a real 3G or 4G network can slow things down differently than a simulation. Minor scrolling, gestures or delays in loading interactive elements can seem trivial in an emulator, but in reality hinder the user experience.

In 2024, test primarily: 390×844 (iPhone), 360×640 (Android), 768×1024 (tablet), 1920×1080 (desktop). These resolutions cover about 70% of users. Also check the landscape orientation on phones - more and more people are browsing by holding the device horizontally, and the layout in such a mode can cause shifting of elements or difficulties with forms. For example, in an online store, payment form fields may obscure at the keyboard, which seems like a minor inconvenience, but can lower the purchase completion rate.

Testing functionality and user experience

A fast site is a must, but speed alone is not enough - the user still has to find what to look for and perform the intended action. The technically best site can have a terrible UX. Here you need tools that show actual visitor behavior, not just our assumptions.

Usability testing tools

Hotjar is like a CCTV camera for your site. Session recordings reveal how people actually navigate the site - where they click, how they scroll, where they stop. You can see the frustration in real time: someone trying to click an item that isn't a link, or looking for a button where there isn't one. Example: a user clicks on a product image thinking it's an add to cart button - a lightbox opens instead of a shopping cart, and abandons the process.

Heat maps reveal even more. Red areas show attention-grabbing areas - is that really where you want to lead your eyes? Sometimes we find that users ignore the main CTAs and click on decorative graphics. This can suggest that the site design is misleading, or the content priorities are unreadable.

Crazy Egg works similarly, but has better segmentation tools. You can compare the behavior of users from different traffic sources - those from Google behave differently than those from Facebook or email. This is important when planning campaigns: ads directing traffic from social often need a different page layout than organic traffic.

Heatmap interpretation requires common sense. A lot of clicks does not always mean success - it could be where people get lost. Conversely, a lack of clicks on an important button is an alarm signal. Look at the data in the context of the user's path: a single indicator rarely gives the full picture.

A/B testing concludes the optimization process. Google Optimize lets you test different versions of elements on live traffic. Change the color of a button, header or form position - and see which version converts better. VWO and Optimizely offer more features (better segmentation, multivariate testing), but their cost is often higher - it's worth comparing this with the expected profit.

Testing forms and conversion processes

The purchasing path is a chain - a weak link spoils the whole. Go through each step as a regular customer. How many clicks away from the order? Does each page clearly tell you what to do next? Are there no hidden costs at the end? A small change, like a precise description of delivery costs or the addition of lead time information, can significantly reduce abandoned shopping carts.

Abandonment points will be indicated by Google Analytics in conversion funnels. If 50% of users leave on the payment page, the problem lies there. It could be an overly complicated form, a lack of a popular payment method (e.g., no BLIK/Apple Pay/PayU), or simply a gateway that doesn't work. In one project, a simpler payment form and the addition of mobile payment reduced rejections by several percent.

Contact forms require special attention. Microsoft Clarity offers free session recordings - you'll see if people are struggling with specific fields. Maybe email validation is too restrictive (blocking addresses with a plus, for example), or CAPTCHA doesn't load on older phones. Sometimes just changing the order of fields, adding a password hint or enabling autocomplete can raise the number of completed forms.

Also test automated emails - order confirmations, newsletters, reminders. Do they end up in spam? Do they display correctly in Gmail and Outlook? Tools like Litmus or Email on Acid show previews of messages in different email clients and on devices. A practical example: an order confirmation that looks good on desktop may not display the logo in the mobile app or be marked as spam due to SPF/DKIM deficiencies. Check this before you send hundreds of messages.

Safety and regulatory compliance

A user enters personal information in a form. Are they safe? A hacker attacks the site in the middle of the night. Will the system hold up? These are not questions just for large corporations. Every company collects customer data, so any company can become a target - even a small online store with a simple order form.

Website security audit

Basic safety tests do not require a specialist. Tools such as Mozilla Observatory can scan a site for free and pinpoint major vulnerabilities. They check HTTP headers, SSL configuration and basic protection against XSS attacks. The result can suggest where to start patching.

SSL is an absolute minimum in 2024. However, not every certificate gives the same protection. Qualys SSL Labs tests encryption configurations and gives a grade from F to A+. A grade below B probably indicates serious problems - such as using outdated versions of TLS or weak ciphers - that need to be fixed immediately.

Sucuri SiteCheck helps detect malware and injected code. It scans files and highlights when a site gets blacklisted by Google. VirusTotal additionally lets you analyze files manually, which is sometimes useful when you suspect specific infected files.

Basic penetration testing can be commissioned for as little as a few hundred zlotys. A specialist will check forms (e.g. SQL injection vulnerability), user session management, and administrator account permissions. It's an investment that can save a company's reputation - better to pay now than to clean up after a data leak later. A practical example: a simple pentest can detect the absence of a limit on login attempts, which seems insignificant, but in practice enables brute force attacks.

RODO compliance and accessibility

Accessibility for people with disabilities is not an option, it's an obligation. Tools such as WAVE detect basic problems: missing image descriptions (alt), bad color contrast, or incorrect header structure. These errors make it difficult for people using screen readers to use the site.

axe DevTools integrates with the browser and checks accessibility in real time as you browse the site. Lighthouse in Chrome has a built-in accessibility audit - usually enough for a first diagnosis. But automated tests won't catch everything; it's worth checking the site manually with NVDA or VoiceOver to see how the site behaves in real life.

RODO requires a data-conscious approach. CookieBot scans cookies and helps generate privacy policies. It also checks that consents are collected in a legal manner - for example, separate marketing consents from essential cookies. Automated tools are a good start, but they are no substitute for an expert review. A lawyer will check the terms and conditions, and a UX specialist will test accessibility with a screen reader; together they can identify specific changes. The approximate cost of such a review is 2-5 thousand zlotys.

The penalty for non-compliance with RODO can be up to 4% of a company's annual turnover, so the financial risk is real. Privacy International offers free privacy policy templates, but every company has different needs - it is better to customize documents for a specific business than to use a ready-made one without modifications.

Creating a testing process in the company

The best tools are half the battle. The other half is an orderly process that works regardless of who is currently handling the site. Without such a system, it's easy for chaos to occur - and it usually ends in missed errors and wasted time.

Building a check-list of tests

The checklist is your autopilot in testing. It's a simple document - Excel or Google Sheets - where you check off each item you've checked off. When you're working under pressure, without a list, it's easy to miss something important.

The template for an online store will be different from that for a corporate site. The store needs to test shopping cart, payment, email notifications and returns processes. The service site should focus on contact forms, a booking calendar or CRM integration.

An example of a basic list:

• Contact form works on desktop and mobile
• All links lead to the right places
• Page loads in under 3 seconds
• SSL active on the entire site
• Meta descriptions filled in on the main pages

Add practical points: e.g., testing payments on a sandbox, verifying webhooks for payments, checking the sending of emails under different scenarios (order confirmation, password reset). Such a concrete description of steps makes testing easier and reduces the risk of missing important elements.

Assign specific tasks to specific people. Marketing checks content and SEO, the technical person tests forms and performance, and the business owner evaluates the whole thing from the customer's perspective. In practice, this helps avoid the "everyone thinks someone else checked" situation.

Determine the frequency of testing: a new site should be tested before publication, a working one is worth checking monthly, and after any major change - immediately. Document the results in a spreadsheet with dates, comments and a list of problems found - this creates a history that is easy to analyze later.

When it's a good idea to outsource testing

Custom testing has limitations. Knowing the site by heart, it's easy to automatically miss places that may cause problems. An outside specialist will take a fresh look and may find errors you overlooked.

An external audit is worth considering before a major ad campaign, after a migration to a new server, when security issues are suspected, or when conversions are dropping for no apparent reason. An outside firm is likely to detect subtle UX errors, problems with user sessions or misconfigured caches that seem normal to an internal team.

How to choose a good agency? Ask for examples of audits for similar companies and the specific tools they use - not just a general "we'll check manually." A good contractor will provide a list of items to review (e.g., security testing: SAST/DAST, performance testing, UX, accessibility), and an estimate of the work time.

The cost of a professional audit is usually 2-8 thousand zlotys, depending on the size and complexity of the site. Sound like a lot? Compare that to the potential consequences: a store crash during Black Friday can mean lost revenue of tens of thousands, and sometimes much more.

Budget testing like insurance - It is better to pay smaller amounts on a regular basis than to fix a disaster at one time. Monthly monitoring of basic functions (payments, forms, uptime) is usually £200-500. Rebuilding a reputation after a major hack can be costly or even impossible to fully recover from.

Monitoring and responding to problems

You already have a testing process in place, but what happens between checks? A website may crash in the middle of the night, a form may stop sending submissions over the weekend, and you only find out about it on Monday from an email from a frustrated customer. Continuous monitoring instead of firefighting allows you to manage problems before they grow.

UptimeRobot checks site availability every 5 minutes for free. It pings the main site and subpages and can send an SMS when something stops working. Site24x7 goes a step further - it also monitors performance, checks the operation of forms and tests entire user paths (e.g. from entering the site to finalizing payment).

StatusCake and Pingdom offer monitoring from multiple geographic locations. A server in Poland may work flawlessly, while connections from Germany or the US will have problems. If you're selling internationally, it's a good idea to know about such differences before your customers do.

Alert systems must be balanced. Too many alerts mean you start ignoring them. Too few alerts, on the other hand, means you only find out about the failure after the damage is done. Set thresholds: an alert when response time increases beyond 5 seconds, an immediate notification when total unavailability. You could also consider different channels - SMS for critical failures, Slack or email for less urgent ones.

A crisis plan saves nerves and reputation. Who contacts the web host at 3 in the morning? What phone numbers are on hand? Is the backup up to date and can it be restored quickly? These questions are better asked before a crisis. Prepare a list of contacts, panel permissions and rolling procedures (who does what on the first, second and third).

Prepare a communication template for customers, too. Brief: "Sorry for the technical problems, we are working on a solution" sounds better than radio silence. A consistent message on your homepage, social media and newsletter will reduce uncertainty. Practical example: during a payment failure, publish information about alternative payment methods and expected repair time.

Google Analytics allows you to observe traffic drops in real time. A sudden drop may suggest an ad problem, a deployment error or a DDoS attack. The sooner you identify the source (e.g., a bug in one of the plugins after deployment), the lower the losses. Probably the best strategy is a combination of tools - synthetic monitoring, server logs and user behavior analysis - to get the full picture.

Summary and next steps

Start with the basics: PageSpeed Insights, UptimeRobot, checklist. These three tools probably cover about 80% of common problems and are available for free. Add to that Hotjar - heatmaps and session recordings will quickly show where users are getting lost. For example: if PageSpeed indicates slow loading images, and Hotjar shows that users are not scrolling further, you have a clear course of action.

The first step is to audit the current site. Check loading times, test forms on mobile and go through the purchase process as a customer would. Make note of any errors - such as lack of validation on mobile devices or incorrect redirects after form submission - and prioritize fixes that are most likely to increase conversions.

Long-term systematic testing builds competitive advantage. Regular testing usually translates into higher conversions, better visibility in Google and fewer technical problems. Satisfied customers are less likely to churn and more likely to recommend the company to friends - a cumulative effect that can return the investment many times over.

Get started today. Enter your site address into PageSpeed Insights. Test at least one form on your phone - even a brief check can reveal a critical error. It's a small step toward greater reliability and real revenue growth.

Need help implementing a testing process? Contact us - we can show you how to implement systematic testing and corrections without spending your budget wastefully on unnecessary tools.