Website optimization service, compared on published evidence

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How to buy website optimisation

1. Name the metric before the vendor does. Decide whether you are buying speed, conversion rate or search visibility. Each has a different baseline, measurement window and specialist. A proposal promising all three at one price is promising the cheapest version of each.
2. Establish a baseline you did not buy. Pull your own numbers first: field performance data, current conversion rate by template, and search impressions. If the vendor supplies both the baseline and the improvement, you have no independent way to check the claim.
3. Agree the test discipline. Conversion work only proves anything if changes are tested on a large enough sample. Ask how the vendor decides a test has finished, and what happens when it comes back flat, because most tests do.
4. Keep the code. Optimisation often lands as tag manager scripts and third-party widgets. Agree what gets written into your own codebase and what leaves with the vendor, or you inherit a site that slows down the day the contract ends.

Speed: what Google actually measures

Google publishes the thresholds, so this part is not a matter of opinion. Core Web Vitals covers loading, interactivity and visual stability: Largest Contentful Paint within 2.5 seconds, Interaction to Next Paint of 200 milliseconds or less, and Cumulative Layout Shift of 0.1 or less. A page is treated as passing when it meets all three at the 75th percentile of page loads, measured separately for mobile and desktop.

That definition matters when you read a proposal. Lab tools score a single simulated load and can be improved by tuning the test rather than the site. Field data reflects real visitors on real devices and networks, which is what Google reports on. Ask which the vendor will report against, and ask for the mobile figure specifically, because that is usually where the failure sits.

Conversion: where the money usually is

For a site that already has traffic, conversion work generally pays back faster than acquisition work, because it multiplies demand you have already bought. The honest version of the trade is unglamorous: fixing forms that ask for too much, making the phone number tappable, saying clearly what happens after an enquiry, removing steps rather than adding persuasion. The tactics that get written about, colour changes and urgency timers, have the weakest and least durable effects.

The catch is statistics. A site with a few hundred conversions a month cannot resolve a small uplift in a reasonable window, so most tests will be inconclusive, and a vendor reporting a win every month is reporting noise. On low-traffic sites the right work is qualitative: session recordings, form abandonment analysis and talking to buyers, with changes shipped on judgement and then monitored rather than split-tested.

What it should cost

Optimisation is bought either as a fixed-scope project (an audit plus a defined set of fixes) or as a monthly retainer that buys a rate of experiments. Projects suit a site with a known problem; retainers suit a site with enough traffic to keep a test queue full and settle a test inside a month.

Ask the vendor to show that arithmetic on your own numbers before you commit to twelve months of it. If your traffic cannot resolve a test in under a quarter, the retainer is buying opinions rather than evidence, and a project plus a clear handover will be better value.

Questions people actually ask

Is website optimisation the same as SEO?

No. SEO changes what search engines can find, understand and rank. Optimisation in the conversion sense changes what a visitor does once they arrive, and in the performance sense changes how quickly the page becomes usable. They overlap at speed, which Google measures, but they are bought from different specialists.

How much traffic do I need before conversion testing is worth it?

Enough conversions rather than enough visitors, because the test resolves on outcomes. If the site produces a handful of enquiries a week, a split test takes months to say anything, so spend the budget on qualitative research and the obvious fixes instead.

Do Core Web Vitals affect rankings?

They form part of how Google assesses page experience, but they do not substitute for relevance: a fast page about the wrong thing does not rank. Treat the published thresholds as a floor to clear, and fix them mainly because visitors abandon slow pages.

Who should own the changes?

Whoever maintains the site. Optimisation that lives only inside a tag manager is fragile, slows the page down and disappears when the vendor does. Agree in the contract which changes are merged into the codebase and who reviews them.

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