Choosing a web developer is one of the most important business decisions an entrepreneur can make. A bad choice costs you twice – first for the development, then for the rebuild. In this article, we walk through eight specific tests and questions you can use to assess a web developer’s real level before signing a contract.
Test 1: Core Web Vitals – Google measures whether your site is fast
Page load speed is no longer just a user experience question – it’s a direct SEO ranking factor. Google uses Core Web Vitals metrics when ranking search results:
- LCP (Largest Contentful Paint) – how quickly the largest visible element on the page loads. Good: under 2.5 seconds.
- INP (Interaction to Next Paint) – how quickly the page responds to a user action (a click, an input). Good: under 200 ms. In 2024, INP replaced the old FID metric.
- CLS (Cumulative Layout Shift) – how much elements on the screen “jump around” while the page loads. Good: under 0.1.
How to test: Go to pagespeed.web.dev and enter one of the developer’s previous projects. A score below 50 (on mobile) is a red flag. Ask the developer how they optimize Core Web Vitals – if the question draws a blank stare, that’s an answer in itself.
Test 2: Mobile comes first, not as an afterthought
In Estonia, over 60% of web traffic comes from mobile devices. “Mobile-first” is no longer a trend – it’s the standard. Yet many developers still build the desktop view first and “fix up” mobile later – the result is inevitably a compromise.
How to test: Take a site from the developer’s portfolio and open it on an actual mobile phone (not just in the “mobile view” of the browser’s developer tools). Check:
- Are the buttons large enough to tap with a finger (min 44×44 px)?
- Is the text readable without zooming?
- Is the page free of horizontal scrolling?
- Are the forms usable – does the keyboard avoid covering important content?
Test 3: Code quality – W3C and beyond
The W3C Validator (validator.w3.org) is a good starting point. It checks whether the HTML is semantically correct. A rough guide:
- 0–5 errors – excellent
- 6–25 errors – acceptable
- Hundreds of errors – a serious problem
But W3C is only the beginning. Today, these matter too:
- Semantic HTML – are the right elements used (article, section, nav, main, an h1-h6 hierarchy)? This affects both SEO and accessibility.
- Clean CSS – can the code be maintained sensibly later on? Ask whether they use CSS variables (custom properties) and a methodology (BEM or similar).
- JavaScript loading strategy – are scripts loaded with defer/async? Render-blocking scripts slow down page rendering.
Test 4: Security – what a good developer does by default
Security holes aren’t visible from the outside. But poor development practices mean your site is an easy target for hackers. Ask the developer about:
- HTTPS and SSL – the self-evident minimum in 2026
- WordPress updates – do they set up automatic security patches?
- Security plugins – Wordfence, Sucuri or similar
- Backups – is there an automatic daily backup on an external server?
- SQL injection and XSS protection – is user input sanitized? Especially important for contact forms and search functions.
- File permissions on the server – wp-config.php must be protected (chmod 600 or 640)
A good test: ask the developer, “How do you protect the site against hacking?” A professional answers specifically. A vague answer is a red flag.
Test 5: SEO readiness already during development
Adding SEO after the site is finished is ten times harder than building it in from the start. Ask whether the developer accounts for:
- URL structure – short, descriptive URLs with keywords (not /page?id=123)
- H1-H6 hierarchy – exactly one H1 per page, a logical heading hierarchy
- Schema markup – structured data (Organization, LocalBusiness, BreadcrumbList, FAQ) helps Google understand the page better
- XML sitemap – generated automatically and submitted to Google Search Console
- Canonical URLs – to avoid duplicate content problems
- Open Graph and Twitter Card meta – the correct preview when shared on social media
- robots.txt – configured correctly, with admin and duplicate results blocked
Test 6: Ready-made theme vs. custom build – an honest answer
Both are legitimate choices – it depends on the goal and the budget. What matters is that the developer explains the difference honestly.
- Premium theme (e.g. Divi, Avada, Elementor) – faster, cheaper. Suitable for a simple brochure website. Downsides: bloated code, slower, harder to customize, ties you to the theme’s developer.
- Custom build (custom theme) – more expensive, but cleaner code, better performance, full control over the design. Suitable for companies with specific needs.
- Page builder solution (Gutenberg + ACF) – a good compromise: flexible, yet cleaner than heavy page builders. Marketing Sharks uses this approach.
Ask the developer: “Why are you choosing this particular solution?” A good developer explains the trade-offs instead of just selling what they know best.
Test 7: Accessibility – often forgotten, but increasingly important
The European Union’s Web Accessibility Directive requires public sector websites to comply with the WCAG 2.1 AA standard. It isn’t mandatory for the private sector yet, but that is changing – and besides, an accessible site is better for all users.
Ask the developer whether they account for:
- Sufficient color contrast between text and background (min 4.5:1 for normal text)
- Alt text on images
- Keyboard navigability (the Tab key)
- ARIA markup on more complex components
- Focus indicators (a visible cursor during keyboard navigation)
Quick test: Go to one of the developer’s portfolio sites and press the Tab key. Can you see where the focus is at any given moment? If not, accessibility is a problem.
Test 8: Project management and communication
Technical competence is only half the story. The best code won’t help if the project drags on, communication is poor, and the end result differs from what was promised.
Ask before signing the contract:
- What does the workflow look like? Are there wireframes and design mock-ups before development starts?
- Who is my point of contact? How often do we get updates?
- What happens if we discover mid-development that something needs to change?
- What are the exact payment milestones and delivery dates?
- Can I edit the content myself after handover? Is training included?
- What are the warranty terms after handover?
A professional agency answers all of these questions clearly and puts them into a written contract.
Quick checklist: 5 things to check right away
- pagespeed.web.dev – test the developer’s previous work. The mobile score should be above 60.
- validator.w3.org – check that the HTML validates
- Google search “site:their-portfolio-site.ee” – you’ll see how many pages Google has indexed (it should be a sensible number, not 0)
- Ask for 2–3 references – actually call them, don’t just send an email
- Read the contract – who owns the final code and the domain? What happens if the developer goes bankrupt?
Marketing Sharks has built and maintained dozens of websites and online stores over more than ten years – from small businesses to complex B2B portals. We know what works and what doesn’t. Check out our web development service or ask for a free consultation – we’ll review the current state of your site.
If your project is an online store, be sure to also check out our service for building an online store.
Quality web development goes hand in hand with search engine optimization, so take a look at our SEO service as well.
When planning a new site, an overview of how building a website works will also help you move forward.
