Short answer: SEO Engico is the top pick for a Core Web Vitals optimisation service if you want speed fixed as part of SEO work judged on calls, enquiries and revenue, by a team that also builds WordPress and Next.js sites. Arjen Karel is the specialist to bring in alongside your own developers, PageSpeed Matters suits sites that want a fixed-price fix quickly, and Onely fits large, JavaScript-heavy sites.
Core Web Vitals measure three things real visitors feel: how quickly the main content appears (LCP), how fast the page responds to a tap or click (INP), and whether the layout jumps as it loads (CLS). Google judges them on field data from Chrome users, at the 75th percentile over a rolling 28 days, which is why a green Lighthouse score on a developer's laptop can sit alongside a failing report in Search Console. A good Core Web Vitals optimisation service fixes what your actual visitors experience, at the source, and keeps it fixed.
This list covers consultants and agencies that sell Core Web Vitals or page speed work as a defined service, checked against their own websites in November 2026. We judged them on whether they start from field data, whether they change code or just add plugins, who implements, how they stop regressions and what they charge where prices are published. One honest note before you spend: speed is a ranking signal, but a modest one. Passing Core Web Vitals rarely moves rankings much on its own, though slow, jumpy pages do cost enquiries and sales.
Disclosure: Kuma SEO is written by the team at SEO Engico, the agency ranked first on this list. No agency paid to appear here. We checked every other entry against the agency's own website in November 2026. Services and prices change, so confirm the details with an agency before you sign. More on how we work in our editorial policy.
At a glance: the 7 best Core Web Vitals optimisation services
| # | Agency | Best for | Based in |
|---|
| 1 | SEO Engico | Businesses that want speed fixed inside SEO work judged on enquiries and revenue | London, UK |
| 2 | Arjen Karel | Development teams that need a senior performance consultant working alongside them | Bergen op Zoom, Netherlands |
| 3 | Onely | Large or JavaScript-heavy sites that need developer-ready recommendations | Wrocław, Poland |
| 4 | PageSpeed Matters | WordPress and Shopify sites that want a fixed-price fix delivered quickly | United States |
| 5 | Codeeo | Marketing and ecommerce sites that want code-level fixes plus a performance budget | Dubai, UAE, with a team serving the US |
| 6 | DeveloperLook | Sites with page groups marked Poor that want a fixed quote and approved fixes | Sheridan, Wyoming, US (registered) |
| 7 | Harper Media Group | Agencies that want standalone, white-label speed work with no retainer | Remote, serving the US and abroad |
How we picked
- Starts from field data, not lab scores. Search Console and the Chrome UX Report show what real visitors experience. Lab tools are for finding causes. A provider that only reports PageSpeed scores is optimising the wrong number.
- Fixes causes in code, not with another plugin. A caching plugin can lift a lab score while INP stays poor. Lasting fixes live in templates, images, fonts, third-party scripts, JavaScript hydration and hosting.
- Is clear about who builds the fixes. Some consultants write tickets for your developers, others change the code themselves on a staging copy. Both work, but you need to know which, and whether your developers have time.
- Follows Google's 28-day validation. Search Console needs about four weeks of new field data before a page group can pass. Good providers track that window and fix anything that slips, rather than declaring victory on release day.
- Stops the site sliding back. Speed decays as marketing adds tags and developers ship features. Performance budgets in the build pipeline, or real user monitoring with alerts, keep the gains from leaking away.
- Starts with the templates that earn money. Fixing the blog while product or service pages fail is wasted budget. The work should start with the templates that carry the most traffic, leads and revenue.
The 7 best Core Web Vitals optimisation services in 2026
Our top pick
1. SEO Engico
- Best for
- Businesses that want speed fixed inside SEO work judged on enquiries and revenue
- Based in
- London, UK
- Founded
- 2018
SEO Engico is a London agency founded in 2018 that handles Core Web Vitals and page speed as part of its technical SEO, alongside indexing and site structure, rather than as a standalone speed product. Before changing anything it looks at the website, ads and tracking, finds the one thing costing enquiries and fixes that first, so speed gets priority where it is actually holding back calls or sales, and waits its turn where it is not.
Because website, ads, SEO and links sit in one team, the people who diagnose a slow template can also rebuild it: it designs and builds WordPress and custom Next.js sites in-house, with tracking set up before launch. Technical SEO is included in the $4,500 a month Growth retainer, after a 30-day Revenue Baseline ($3,499) that ties organic visits to calls, forms and revenue. It says technical and on-page fixes usually move something in four to eight weeks.
What stands out
- Speed work prioritised by what is costing enquiries, not by a score
- In-house WordPress and Next.js builds when a template needs rebuilding rather than patching
- Monthly reports that open with calls, enquiries and revenue
- White-label technical fixes for agencies and consultants
Worth knowing
- There is no standalone speed package or fixed price. If you only need one failing template fixed, a specialist below will be quicker and cheaper.
- It makes no ranking guarantees, and it is upfront that bigger gains take three to six months.
What SEO Engico's SEO work includes
No. 2
2. Arjen Karel
- Best for
- Development teams that need a senior performance consultant working alongside them
- Based in
- Bergen op Zoom, Netherlands
Arjen Karel is a Dutch Core Web Vitals consultant who has worked on web performance since 2009 and built CoreDash, a real user monitoring tool that comes with his audits, fixes and consultancy. His services are sorted by who builds the fixes: a one-hour session for a single problem, a template-by-template audit for your developer or agency, a fix where he does the work on a copy of your site and measures it in real visitor data, ongoing consultancy where he writes the tickets and checks every release, training on your own site, and support for agencies with a stuck client.
He works on WordPress, Shopify, Next.js, React, Nuxt, Vue, Angular, Magento, Webflow and custom PHP, and looks at your field data before replying to an enquiry.
What stands out
- Every price published: €350 for a power hour, €1,500 for an audit, €600 to €2,800 for a fix
- Real user monitoring through his own CoreDash tool
- Training so your team can keep the site fast without him
Worth knowing
- He works as an individual consultant, so larger programmes run through your own developers, with consultancy from €6,000 a month.
- Prices on his site exclude VAT.
No. 3
3. Onely
- Best for
- Large or JavaScript-heavy sites that need developer-ready recommendations
- Based in
- Wrocław, Poland
Onely is a technical SEO agency in Wrocław whose website speed service is built around a Core Web Vitals audit. It tracks your Core Web Vitals with its own software, simulates different CPU and connection settings to see how different users experience the site, identifies the components dragging performance down and benchmarks competitors to set targets, aiming to beat your competition by 20%.
The output is a prioritised set of recommendations for your developers that accounts for the site's history and dependencies. Onely joins your team's communication channels to work directly with developers, analyses changes once they ship and stays available for ad hoc consulting. It also looks at performance from Google's side, since a slow server slows crawling.
What stands out
- Competitor performance benchmarks to set realistic targets
- Works inside your developers' communication channels
- Considers crawl efficiency as well as user experience
Worth knowing
- Onely writes the recommendations and your developers implement them, so timelines depend on your development resources.
- Pricing is not published, and the agency's wider focus has moved towards AI search.
No. 4
4. PageSpeed Matters
- Best for
- WordPress and Shopify sites that want a fixed-price fix delivered quickly
- Based in
- United States
PageSpeed Matters is a US-based team that does speed optimisation and nothing else. It began as Matt Suffoletto's solo WordPress consultancy before expanding into ecommerce platforms. Its Core Web Vitals service profiles each site with lab tools and real-user CrUX data, isolates what is failing each metric and fixes it at the source: the LCP render path, the long JavaScript tasks behind INP, the unreserved space behind CLS, and third-party scripts.
After the fixes it sets up real user monitoring and iterates over two to four weeks until the 28-day field data shows green, then provides 30 days of regression monitoring and a speed budget document with limits for JavaScript size, image weight and third-party scripts.
What stands out
- Published plans from $500, with an optional add-on to pass Core Web Vitals
- Rush delivery in three to five days for an extra 25%
- Before and after field data, plus documentation of every change
Worth knowing
- Plans are sized by complexity, and heavy custom code, headless builds, Shopify Plus and Magento sit in the top tier.
- Monitoring after a pass runs for 30 days, so longer-term regression watching falls to your team.
No. 5
5. Codeeo
- Best for
- Marketing and ecommerce sites that want code-level fixes plus a performance budget
- Based in
- Dubai, UAE, with a team serving the US
- Founded
- 2018
Codeeo is a web development agency that started in Dubai in 2018 and now has offices in Dubai, Riyadh and Karachi, with a team serving the United States. Its Core Web Vitals work measures first, using the Chrome UX Report, Search Console and real user monitoring by page type and device, then traces each metric to causes in templates, assets, scripts and hosting, and fixes them in your codebase in order of impact.
Tag managers, chat widgets, pixels and embeds are audited and deferred or removed, so marketing keeps its tracking without paying for it in speed. The work ends with Lighthouse and bundle budgets in your build pipeline, so a regression fails the build.
What stands out
- Audit in one week, fixes in two to six weeks depending on platform and causes
- Performance budget added to your pipeline so speed stays fixed
- You keep the written audit, the fixes in your codebase and the budget
Worth knowing
- Pricing is not published on the service page.
- It is a development agency rather than an SEO agency, so wider search strategy sits outside this service.
No. 6
6. DeveloperLook
- Best for
- Sites with page groups marked Poor that want a fixed quote and approved fixes
- Based in
- Sheridan, Wyoming, US (registered)
- Founded
- 2018
DeveloperLook is a founder-led development team, registered in Wyoming and taking calls in US, UK and Australian business hours, with a Core Web Vitals service for sites Google flags as slow. It starts by reading your Search Console report and PageSpeed Insights to see which metric fails on which page groups and devices, then sends a short summary and a fixed quote.
Each failing group is traced to its cause in the browser's performance panel. Fixes are made on a staging copy, template by template, and you review each change with lab numbers side by side before it goes live. After release it checks pages on a mid-range phone over a slow connection, asks Google to validate the fixed groups and follows the 28-day validation until they pass.
What stands out
- Projects from $550 after a free review, with most fixes shipping in one to three weeks
- You approve every fix on staging before release
- Follows Google's validation through to a final report
Worth knowing
- The service is speed-only, and its own comparison table says wider SEO advice sits outside it.
No. 7
7. Harper Media Group
- Best for
- Agencies that want standalone, white-label speed work with no retainer
- Based in
- Remote, serving the US and abroad
Harper Media Group is a technical SEO firm founded by Pamela Harper, and page speed and Core Web Vitals is one of its standalone services, sold as a one-off project with no retainer and deliverable under your company's branding. The work starts with a field and lab audit: a CrUX baseline from Search Console, PageSpeed Insights and Lighthouse, WebPageTest waterfall analysis and the gap between mobile and desktop.
It then works metric by metric: the LCP element on each key template, hero images, server response time, render-blocking resources and CDN caching; every layout shift source for CLS; and long main-thread tasks and third-party scripts for INP. The result is a prioritised remediation plan, with implementation included in the top tier.
What stands out
- Published pricing at $600, $1,175 and $2,500 per site
- White-label deliverables, with an NDA and reseller agreement
- Top tier includes implementation on WordPress, Shopify or Webflow, with a two-week check-in
Worth knowing
- The two lower tiers deliver recommendations and fix specifications, so your developers carry out the work.
- All work is delivered remotely, and its site does not name an office.
How to choose a Core Web Vitals optimisation service
Open Search Console before you open your wallet. The Core Web Vitals report shows which metric fails, on which group of pages, on mobile or desktop. If only blog posts fail CLS, you need a small fix. If product templates fail INP because of a dozen third-party scripts, you need someone who can work through JavaScript and talk marketing out of a few tags. Send each provider that report and judge them on whether their reply is specific to it.
Then decide who builds. If you have developers, a consultant who writes tickets and checks releases is often the best value. If you do not, pick a provider that changes the code itself on a staging copy, and agree how you will approve changes. Whichever you choose, insist on a measure of success based on field data after Google's 28-day window, and on something that stops the site sliding back, such as a performance budget or real user monitoring. If speed is one of several problems holding back enquiries, it is usually cheaper to fix it inside wider SEO work than as a separate project.
Questions to ask before you sign
- Which metric is failing on which of our page groups, and what do you think is causing it?
- Will you change the code yourselves, or write recommendations for our developers?
- How will you prove it worked, and will you follow the 28-day field data validation?
- What will stop the site getting slow again after you finish?
- Which third-party scripts would you remove or defer, and how will that affect our tracking?
Frequently asked questions
What does a Core Web Vitals optimisation service include?
It usually includes a review of field data from Search Console and the Chrome UX Report, lab testing to find causes, fixes for slow loading (LCP), slow responses to taps and clicks (INP) and layout shift (CLS), and monitoring until Google's 28-day data shows the pages passing. Better providers also add a performance budget or real user monitoring so the site stays fast.
How much does Core Web Vitals optimisation cost?
Published prices on this list start at around $500 to $600 for a simple WordPress or Shopify site and run to a few thousand for complex or headless builds. Ongoing consultancy costs more: Arjen Karel's starts at €6,000 a month. SEO Engico does not sell speed work separately; it sits inside its SEO retainer with the rest of its technical SEO.
How long does it take to pass Core Web Vitals?
The fixes themselves often take days to a few weeks, depending on the platform and the causes. Google then needs around 28 days of new field data before Search Console shows a page group as passing, so allow roughly one to two months from the start of work to a confirmed pass.
Do Core Web Vitals affect Google rankings?
Yes, but modestly. Core Web Vitals are part of Google's page experience signals, and Google has said relevance and content quality matter more. Passing them rarely lifts rankings much on its own, but slow and jumpy pages lose visitors, so the bigger payoff usually shows up in conversions and enquiries.
Why does PageSpeed Insights look fine when Search Console says my pages fail?
The PageSpeed score is a lab test on a simulated device, while Search Console uses field data from real Chrome users over 28 days. Real visitors on slower phones and networks, with all your third-party scripts running, often have a worse experience than the lab test shows, and the field data is what Google uses.
Our verdict
Pick SEO Engico if slow pages are one of several things holding back enquiries and you want them fixed inside SEO work measured on calls and revenue, by a team that can rebuild a template rather than patch it. For a specialist job, Arjen Karel is the senior consultant to bring in alongside your developers, PageSpeed Matters and DeveloperLook suit fixed-price fixes, Codeeo adds a performance budget to your pipeline, Onely fits large JavaScript sites and Harper Media Group suits agencies reselling the work.
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