A landing page build checklist for developers and marketers

Most landing page problems aren't design problems. They're handover problems.

The marketer assumes the developer set up tracking. The developer assumes the marketer tested the form. The page launches, ad spend starts, and a week later someone notices the conversions report is empty, or the form has been sending leads to an inbox nobody reads.

A shared checklist fixes most of this. Not a long one: four areas, each with a few checks, and a name next to each. Here's the one I'd want both teams to sign before any paid traffic goes to a page.

1. Speed

A slow landing page wastes the money spent getting people to it. Paid visitors are the least patient visitors you have.

• Test on a mid-range phone over mobile data, not just a fast laptop on office Wi-Fi. Use Lighthouse or PageSpeed Insights, and treat the field data (real users) as more important than the lab score.
• Size images for where they're shown. Serve modern formats (WebP or AVIF) and set width and height so the layout doesn't jump.
• Lazy-load anything below the fold, but never the main hero image.
• Audit third-party scripts. Chat widgets, heatmaps and old pixels add up. Each one should have an owner and a reason to be there.

<!-- Hero image: load early, reserve space -->
<img src="hero.webp" width="1200" height="630" alt="Short description of the image" fetchpriority="high">

<!-- Below the fold: load when needed -->
<img src="feature.webp" width="600" height="400" alt="Short description" loading="lazy">

Who signs: developer runs the test; marketer confirms no script they need was removed.

2. Forms

The form is the whole point of the page. Test it like it is.

• Submit a real test entry on desktop and mobile, then confirm it arrives where it should: the CRM, the right inbox, the right list. Check that someone is actually watching that destination.
• Ask for as little as you need. Every extra field costs completions. If sales doesn't use a field, remove it.
• Make errors helpful. Validate inline, say what's wrong in plain words, and never clear the whole form on one mistake.
• Use the right input types so phones show the right keyboard, and support autofill.
• Protect against spam without punishing real people: a honeypot field or server-side checks before a hard captcha.
• Show a clear confirmation, ideally a thank-you page, which also makes conversion tracking simpler.

<label for="email">Work email</label>
<input id="email" name="email" type="email" autocomplete="email" required>

<label for="phone">Phone (optional)</label>
<input id="phone" name="phone" type="tel" autocomplete="tel">

Who signs: marketer confirms fields and destination; developer confirms validation, spam protection and error states.

3. Tracking

If you can't measure the page, you can't improve it, and you can't defend the budget behind it.

• Agree the conversion event before the build: what counts as a conversion, and where it fires (the thank-you page or a successful submit, not a button click).
• Test every tag with the platform's debug or preview mode, and confirm the conversion appears in the ad platform and analytics.
• Check UTM parameters survive redirects and form submissions, so leads arrive with their source attached.
• Respect consent. Where consent rules apply, tags should wait for it, and the banner should actually work.
• Write down what's installed: one short list of tags, what each one does and who owns it.

Who signs: marketer confirms the events and the reports; developer confirms the tags fire once, in the right place.

4. Accessibility

An accessible page reaches more people, and the fixes usually make the page better for everyone.

• Every image has meaningful alt text, or empty alt text if it's purely decorative.
• Colour contrast passes for text and buttons, including text on images.
• Every form field has a visible label, not just placeholder text that disappears when you type.
• The page works with a keyboard alone: you can reach and use every link, field and button, and you can see where focus is.
• Headings are in order and buttons say what they do ("Get my quote", not "Submit").

Automated checkers catch some of this. A quick keyboard-only run-through catches more.

Who signs: developer.

The sign-off

Put the checklist in a shared doc or ticket with three columns: the check, who owns it, and a tick. Nothing goes live and no paid traffic starts until every line is ticked.

It sounds like process for the sake of process. In practice, it's ten minutes that saves you from finding out a week too late that the page was never working.

Ahmed Vaseer is Founder & CEO - Ingenious Concepts. 80+ projects, ISO 27001 certified via Global CB.