Table of contents
How we vet every listicle
Every agency featured on Web Tonic passes our 84-point editorial review before a single listicle goes live. This is how we vet each pick:
Verified client outcomes: We require real case studies with measurable KPIs — revenue, ROAS, CPA, retention — tied to the exact category being ranked. No cherry-picked wins, no unverifiable numbers.
Independent reputation: We cross-check Clutch, Google, G2, and Trustpilot ratings, and screen for review-bombing or suspicious patterns. Only operators with a consistent, verifiable track record make the cut.
Beyond that, every listing goes through a quarterly re-audit. We check 84 criteria across 6 pillars to make sure it still holds up — here are some of the checks we run:
A website speed and performance agency makes an existing site measurably faster and keeps it that way. That means diagnosing Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift with real-user and lab data, then fixing images, fonts, JavaScript weight, third-party tags, critical CSS, caching, CDN and edge config, database and server response, with performance budgets to stop regression.
We compared 21 providers on platform depth, diagnostic method and disclosure. Only 1 of the 20 external agencies publishes a starting figure, so we quote sourced project ranges instead of guessing.
Which website speed agency should you shortlist?
It depends on your stack. 10up, rtCamp and XWP handle high-traffic WordPress and publishers; Onilab, Classy Llama and Creatuity work Magento and Adobe Commerce; Speed Boostr and Electric Eye fix Shopify; Speed Shop and Bejamas tackle backend and Jamstack.
1. 10up
About: 10up is a fully distributed web engineering agency best known for high-traffic WordPress performance work for major media and enterprise brands. The team focuses on editorial platforms that need to stay fast under massive concurrent traffic, combining front-end optimisation with headless and hosting-partner tuning. Its differentiator is deep publishing-industry experience layered on top of Core Web Vitals remediation.
Key Services: Core Web Vitals audits, WordPress performance engineering, Headless and decoupled architecture, CDN and edge configuration, Editorial platform scaling, Post-launch performance monitoring
Industries Served: Media and publishing, Higher education, Nonprofit, Entertainment, Enterprise B2B
Notable Clients: CNN, Disney, Hearst, Cleveland Clinic, Harvard University
Locations: New York, USA, Remote, Global
Pricing: No public rate card; quoted per scope
Great For: High-traffic publishers, Enterprise WordPress sites, Media brands needing scale
Website: 10up
2. Web Tonic
About: Web Tonic works on speed where it changes money: the templates carrying paid traffic, the tag stack we ourselves put on the site, and the images, fonts and layout shifts that make a landing page feel slow before it finishes loading. We instrument real-user data, fix the render path and third-party weight, then watch conversion rather than a single lab score, alongside the paid search spend the page has to justify. For deep Magento, Rails or headless re-architecture, the engineering specialists below are the right call and we will tell you which one.
Key Services: Growth Marketing, Paid Social, PPC, Meta Ads, SEO, Google Ads, Snapchat Ads, Amazon Ads, Reddit Ads, TikTok Ads, TikTok Shop, GEO-AEO, Webflow Design, Shopify Design, WordPress Design, UGC, Social Media Management, Pay Per Click Management, Marketing Analytics, Analytics Implementation & CDPs, Performance Branding, Performance 360° Audit, Programmatic Ads, OOH Ads, HR Marketing
Industries Served: eCommerce, SaaS, B2B, Construction Professionals, Home Services, SMEs, Health Spa & Wellness, Retail, Legal & Judicial Services, Food & Beverages, Pets, Fitness, Family & Children, Finance & Insurance, Travel, Non-Profits & Organizations, Furniture & Decoration
Notable Clients: WorldRemit, Jack & Jones, Ardene, L'Oréal, Sendwave, Nestlé, Airbnb. Serve Fortune 500 companies and smaller fast-paced startups.
Locations: HQ in San Francisco with notable offices in New York, Chicago, Miami, Toronto, Montreal, Dubai, Singapore, Sydney and more. Offices on five continents.
Pricing: Starting at USD $3,000 per month. Flexible and scalable plans at any time according to your enterprise needs. Book a call to learn more.
Great For: Mid-market to enterprise-level businesses requiring ongoing, on-tap growth and performance marketing services.
Website: Web Tonic
3. rtCamp
About: rtCamp is a managed WordPress and performance agency that pairs Automattic-grade hosting partnerships with dedicated speed remediation for enterprise editorial and automotive sites. The team runs its own audit and hypercare process, moving clients from legacy CMS platforms onto tuned WordPress stacks. It leans on SOC 2 and ISO 27001 certification to reassure large regulated clients.
Key Services: CMS migration to WordPress, Core Web Vitals remediation, Managed WordPress hosting optimisation, Editorial speed at scale, Server and caching tuning, Post-launch hypercare support
Industries Served: News and media, Automotive, Logistics, Enterprise B2B, Broadcasting
Notable Clients: Al Jazeera, Cox Automotive, Manheim, FleetNet America, Grist
Locations: Pune, India, San Francisco, USA
Pricing: No public rate card; quoted per scope
Great For: Enterprise media sites, Automotive marketplaces, Regulated industries needing compliance
Website: rtCamp
4. XWP
About: XWP is a distributed WordPress engineering agency built around performance and platform migrations for global media brands. The company works on decoupled and headless builds where reducing JavaScript payload and render-blocking scripts is central to the engagement. It differentiates through open-source contribution credibility inside the WordPress core performance team.
Key Services: Headless WordPress architecture, JavaScript payload reduction, Core Web Vitals engineering, Platform migration, Enterprise content operations tooling, Performance monitoring integration
Industries Served: Media and publishing, Advertising technology, Entertainment, News, Digital publishing platforms
Notable Clients: News Corp, Vox Media, Rolling Stone, Vice, Penske Media
Locations: Melbourne, Australia, Remote, Global
Pricing: No public rate card; quoted per scope
Great For: Large publishers, Ad-heavy media sites, Headless CMS migrations
Website: XWP
5. Alley
About: Alley is an editorial technology agency that builds and speeds up WordPress sites for newsrooms and mission-driven organisations. Performance work centres on trimming ad-tech and tracking scripts that typically wreck Interaction to Next Paint on news sites, without breaking revenue integrations. The team also advises on caching and CDN setup for spiky traffic events.
Key Services: Newsroom performance audits, Third-party tag reduction, Ad-tech and CWV balancing, WordPress VIP optimisation, Caching and CDN setup, Editorial workflow tooling
Industries Served: News and journalism, Nonprofit and advocacy, Local media, Investigative reporting, Public media
Notable Clients: NBC Universal, New York Post, Chicago Sun-Times, Direct Relief, National Council on Aging
Locations: New York, USA, Washington, USA
Pricing: No public rate card; quoted per scope
Great For: Newsrooms, Nonprofits with high traffic spikes, Ad-supported publishers
Website: Alley
6. Speed Boostr
About: Speed Boostr is a boutique agency that does one thing: makes Shopify and Shopify Plus stores faster without a full theme rebuild. The team audits themes and apps for render-blocking scripts and bloated liquid code, then ships targeted fixes rather than a redesign. It positions itself as the specialist merchants call after a general dev agency could not move their speed score.
Key Services: Shopify theme speed audits, Liquid code optimisation, App and script bloat removal, Image and lazy-load optimisation, Core Web Vitals remediation for Shopify, Ongoing speed monitoring retainers
Industries Served: Direct-to-consumer ecommerce, Fashion and apparel retail, Beauty and personal care, Consumer packaged goods, Shopify Plus merchants
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Remote, Global
Pricing: No public rate card; quoted per scope
Great For: Shopify Plus merchants, DTC brands with bloated apps, Stores that tried a redesign and are still slow
Website: Speed Boostr
7. Speed Shop
About: Speed Shop is an independent consultancy run by Ruby on Rails performance specialist Nate Berkopec, focused on backend and database performance rather than front-end polish. Engagements are deep, hands-on code and infrastructure audits for application teams whose slowness is server-side, not just image weight. It is intentionally small, trading agency scale for specialist depth.
Key Services: Ruby on Rails performance audits, Database query tuning, Server response time optimisation, Background job and queue tuning, Load testing, Performance training for engineering teams
Industries Served: SaaS platforms, Marketplaces, Fintech applications, Subscription software, Developer tools
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Remote, Global
Pricing: No public rate card; quoted per scope
Great For: Rails applications with slow backends, SaaS teams needing database tuning, Engineering teams wanting training, not just a fix
Website: Speed Shop
8. Vaimo
About: Vaimo is a global commerce agency that builds and re-platforms Adobe Commerce, commercetools and BigCommerce storefronts, with performance engineering as a standard part of every build. The team handles headless front ends alongside caching and CDN configuration for large international retailers running many storefronts from one back end. Its scale lets it support enterprise clients across many markets and currencies at once.
Key Services: Headless commerce architecture, Adobe Commerce performance tuning, Multi-storefront CDN configuration, Core Web Vitals remediation, PIM and catalog performance, Composable commerce migration
Industries Served: Fashion and apparel retail, Consumer electronics, Banking and financial services, Home and lifestyle goods, Industrial distribution
Notable Clients: Carhartt, Bauhaus, Bjorn Borg, Al Rajhi Bank, Bunzl
Locations: Stockholm, Sweden, London, United Kingdom
Pricing: No public rate card; quoted per scope
Great For: Multi-region retailers, Enterprise composable commerce buyers, Adobe Commerce merchants
Website: Vaimo
9. Onilab
About: Onilab is a Magento and BigCommerce development shop with a dedicated performance-audit service line for slow ecommerce storefronts. The team runs lab and real-user diagnostics before touching code, then works through server, database and front-end fixes in a defined sprint. It operates with delivery teams split between Eastern Europe and a US-facing office.
Key Services: Magento performance audits, BigCommerce speed optimisation, Database and server tuning, Image and asset optimisation, Progressive web app builds, Core Web Vitals remediation
Industries Served: Fashion ecommerce, Health and wellness retail, B2B wholesale, Furniture and home goods, Specialty retail
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Warsaw, Poland, San Francisco, USA
Pricing: No public rate card; quoted per scope
Great For: Magento merchants, BigCommerce stores needing a speed audit, Mid-market ecommerce brands
Website: Onilab
10. Elogic
About: Elogic is a mid-size ecommerce development agency built around Adobe Commerce, BigCommerce and Salesforce Commerce Cloud, with published performance case studies for household consumer brands. The team publishes a typical project-investment range rather than hiding pricing behind a contact form, which is unusual in this category. Offices across Europe and North America let it staff regionally for large retail clients.
Key Services: Salesforce Commerce Cloud performance tuning, Adobe Commerce speed optimisation, Server and database tuning, Progressive web app storefronts, Core Web Vitals remediation, Ongoing performance monitoring retainers
Industries Served: Consumer electronics, Apparel and footwear, Healthcare products, Sporting goods, Industrial materials
Notable Clients: Disney, Siemens, Philips Healthcare, Hanes, HP
Locations: Tallinn, Estonia, New York, USA
Pricing: From USD $50,000/project
Great For: Enterprise consumer brands, Salesforce Commerce Cloud merchants, Retailers needing published pricing benchmarks
Website: Elogic
11. Bounteous
About: Bounteous is a large digital experience agency with a dedicated performance engineering practice inside its broader Adobe, AWS and commerce partner work. Speed work here is typically bundled into bigger platform modernisation or AI-experience programs rather than sold as a standalone service. Scale and partner certifications make it a fit for enterprise buyers who want one vendor across strategy, build and performance.
Key Services: Enterprise platform performance audits, AWS and Adobe infrastructure tuning, Core Web Vitals remediation, Composable architecture consulting, Personalization performance balancing, Performance monitoring integration
Industries Served: Retail and consumer goods, Financial services, Travel and hospitality, Healthcare, Technology
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Chicago, USA, London, United Kingdom
Pricing: No public rate card; quoted per scope
Great For: Enterprise buyers wanting a single vendor, Adobe and AWS partner-stack clients, Large-scale digital transformation programs
Website: Bounteous
12. Blue Acorn iCi
About: Blue Acorn iCi is an Adobe and Shopify Plus commerce agency that folds performance optimisation into its broader storefront design and development work. The team handles Adobe Commerce and Shopify migrations where speed regressions are a common risk, and treats performance testing as a release gate rather than an afterthought. It operates as part of a larger commerce holding group with deep Adobe partner status.
Key Services: Adobe Commerce performance tuning, Shopify Plus speed optimisation, Release-gate performance testing, Personalization and CDN configuration, Core Web Vitals remediation, Post-launch performance support
Industries Served: Beauty and personal care, Automotive parts, Home furnishings, Apparel retail, Specialty consumer goods
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Charleston, USA, New York, USA
Pricing: No public rate card; quoted per scope
Great For: Adobe Commerce merchants, Shopify Plus brands undergoing a redesign, Consumer goods retailers
Website: Blue Acorn iCi
13. WP Buffs
About: WP Buffs is a white-label WordPress maintenance and performance company that many other agencies quietly outsource speed and uptime work to. Its core offer is an ongoing managed retainer that includes caching configuration, plugin and database cleanup, and monthly Core Web Vitals reporting rather than a one-off audit. The remote team supports both agencies reselling the service and site owners buying direct.
Key Services: Managed WordPress performance retainers, Plugin and database cleanup, Caching and CDN configuration, Uptime and security monitoring, White-label agency partnerships, Monthly Core Web Vitals reporting
Industries Served: Small business websites, Marketing agencies reselling maintenance, Nonprofit organisations, Membership and community sites, Local service businesses
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Remote, Global
Pricing: No public rate card; quoted per scope
Great For: Agencies wanting white-label speed support, Small business WordPress sites, Ongoing maintenance rather than one-off audits
Website: WP Buffs
14. Bejamas
About: Bejamas is a European agency that migrates marketing sites off slow legacy platforms such as Sitecore and WordPress onto Jamstack and headless architectures marketing teams can run themselves. Speed is the headline benefit of the migration work, since static and edge-rendered pages typically start with far better Core Web Vitals than the legacy stack they replace. The team also builds the editorial tooling non-technical teams need to keep publishing without breaking the performance gains.
Key Services: Jamstack and headless migration, Static site and edge rendering builds, Core Web Vitals remediation via architecture change, CMS-to-headless content migration, CDN and edge configuration, Marketing team enablement tooling
Industries Served: B2B SaaS, Insurance, Fintech and payroll technology, Transportation and mobility, Consumer packaged goods
Notable Clients: Danone, Rippling, RudderStack, Bennetts, Veezu
Locations: Wroclaw, Poland, Remote, Global
Pricing: No public rate card; quoted per scope
Great For: Marketing teams stuck on a slow legacy CMS, B2B SaaS companies, Sites needing a Jamstack migration
Website: Bejamas
15. Groove Commerce
About: Groove Commerce is a Shopify and BigCommerce agency that pairs ecommerce marketing services with a dedicated performance and accessibility audit offer. Its speed work usually accompanies a storefront redesign, focused on trimming app bloat and image weight for mid-market direct-to-consumer brands. The team publishes named client logos and results rather than hiding behind anonymised case studies.
Key Services: Shopify and BigCommerce performance audits, App and script bloat reduction, Image and asset optimisation, Accessibility and performance combined audits, Site migration performance testing, Post-launch performance monitoring
Industries Served: Outdoor and sporting goods, Food and beverage, Home goods, Apparel retail, Specialty consumer brands
Notable Clients: Dippin' Dots, Cutter & Buck, GE, Official NASA Gear, Garrett Wade
Locations: Philadelphia, USA
Pricing: No public rate card; quoted per scope
Great For: Mid-market Shopify and BigCommerce brands, DTC retailers wanting a redesign plus speed audit, Brands wanting named case studies
Website: Groove Commerce
16. Yottaa
About: Yottaa is an edge performance platform with a managed-services team that runs continuous Core Web Vitals monitoring and remediation for retail websites, positioning itself as revenue protection rather than a one-time audit. The company operates its own edge network to intercept and optimise third-party scripts and tags without requiring a full front-end rebuild. It sits between a pure SaaS tool and a full agency, selling an ongoing managed performance program.
Key Services: Edge-based third-party script management, Continuous Core Web Vitals monitoring, Render-blocking resource remediation, Real-user monitoring dashboards, Tag governance and vendor management, Performance regression alerting
Industries Served: Fashion and apparel ecommerce, Health and beauty retail, Consumer packaged goods, Specialty ecommerce, Multi-brand retail groups
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Boston, USA
Pricing: No public rate card; quoted per scope
Great For: Retailers with heavy third-party tag load, Teams wanting ongoing managed monitoring, Sites that cannot easily remove marketing scripts
Website: Yottaa
17. Classy Llama
About: Classy Llama is a Magento and Adobe Commerce agency based in the American Midwest that treats performance testing as a standard part of every storefront build rather than an add-on. The team works closely with integration partners such as Klaviyo, Yotpo and ShipperHQ, tuning how those third-party services load so they do not tank Core Web Vitals. It is smaller and more boutique than the Adobe enterprise-tier agencies, which keeps engagements more hands-on.
Key Services: Adobe Commerce performance testing, Third-party integration load tuning, Server and hosting optimisation, Core Web Vitals remediation, Pre-launch load testing, Ongoing Magento maintenance retainers
Industries Served: Specialty retail, B2B distribution, Consumer goods ecommerce, Subscription commerce, Multi-brand retail
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Springfield, USA
Pricing: No public rate card; quoted per scope
Great For: Mid-market Adobe Commerce merchants, Brands with heavy third-party integrations, Teams wanting a boutique, hands-on partner
Website: Classy Llama
18. Wagento
About: Wagento is a B2B-focused ecommerce agency working across Adobe Commerce, BigCommerce and other platforms, with performance built into its storefront delivery process rather than sold separately. The team emphasises reliability past launch day, citing a high client-satisfaction rating on independent review platforms such as Clutch. Global delivery capacity lets it support B2B storefronts with complex catalog and pricing logic that can otherwise slow pages down.
Key Services: B2B storefront performance tuning, Adobe Commerce and BigCommerce optimisation, Catalog and pricing-logic performance review, Core Web Vitals remediation, ERP integration performance testing, Post-launch reliability monitoring
Industries Served: B2B distribution, Manufacturing, Wholesale, Industrial equipment, Specialty B2B retail
Notable Clients: Not publicly named — case studies are anonymised by category
Locations: Minneapolis, USA
Pricing: No public rate card; quoted per scope
Great For: B2B storefronts with complex catalogs, Manufacturers selling direct, ERP-integrated commerce sites
Website: Wagento
19. MGT Commerce
About: MGT Commerce is a managed hosting and performance specialist purpose-built for Magento and Adobe Commerce stores that need fast, reliable infrastructure. The company runs its own tuned AWS-based hosting stack and pairs it with a dedicated speed audit and migration service, rather than treating hosting and performance as separate line items. Client testimonials name recognisable international retail and industrial brands.
Key Services: Managed Magento and Adobe Commerce hosting, Server and database tuning, Free store migration to tuned infrastructure, Core Web Vitals remediation, CDN and caching configuration, 24/7 performance and uptime support
Industries Served: Fashion retail, Consumer electronics, Industrial equipment, Transportation, Global retail brands
Notable Clients: Nintendo, Samsonite, Hyundai, Deutsche Bahn, Caterpillar
Locations: Vienna, Austria
Pricing: No public rate card; quoted per scope
Great For: Magento stores needing tuned hosting, Retailers migrating off slow shared hosting, Global brands needing 24/7 support
Website: MGT Commerce
20. Creatuity
About: Creatuity is an operations-led ecommerce agency that built its early reputation specifically on Magento performance audits before expanding into broader Adobe Commerce and Hyvä theme work. The team is known for publishing detailed technical breakdowns of what actually causes slow storefronts, rather than generic recommendations. Its client roster leans toward mid-market specialty retailers rather than global enterprise brands.
Key Services: Magento and Adobe Commerce performance audits, Hyvä theme migration for speed, Server and database tuning, Core Web Vitals remediation, Technical SEO and speed combined audits, Ongoing performance retainers
Industries Served: Specialty retail, Farm and agricultural supply, Packaging, Athletic apparel, Home improvement retail
Notable Clients: Clear Bags, Family Farm & Home, Fittings Unlimited, Paper People, Rural King
Locations: Plano, USA
Pricing: No public rate card; quoted per scope
Great For: Mid-market Magento retailers, Stores considering a Hyvä theme migration, Merchants wanting a detailed technical audit
Website: Creatuity
21. Divante
About: Divante is a European ecommerce engineering company built around the Alokai composable commerce framework, with performance as a core design principle of every storefront it ships. The team specialises in headless front ends that decouple the storefront from the backend commerce platform specifically to protect Core Web Vitals as catalogs and integrations grow. Its client base spans manufacturing, chemicals distribution and fashion retail across Europe.
Key Services: Composable and headless commerce architecture, Alokai storefront performance tuning, Core Web Vitals remediation, Multi-market CDN and edge configuration, Legacy platform re-platforming for speed, Performance budget setup in CI pipelines
Industries Served: Chemicals distribution, Fashion retail, Industrial manufacturing, B2B wholesale, Multi-market European retail
Notable Clients: Brenntag, Marc O'Polo, Schleich, voestalpine, Schachermayer
Locations: Wroclaw, Poland
Pricing: No public rate card; quoted per scope
Great For: European B2B and B2C retailers, Composable commerce adopters, Manufacturers with complex catalogs
Website: Divante
Quick Comparison Table
| Agency | Key Specialty | Starting Price | Best For |
|---|---|---|---|
| 1. 10up | WordPress performance at scale | Quote-based | High-traffic media publishers |
| 2. Web Tonic | Full-Service Performance Marketing | USD $3,000/mo | Mid-market to Enterprise |
| 3. rtCamp | Managed WordPress speed and hosting | Quote-based | Enterprise editorial platforms |
| 4. XWP | Headless WordPress performance | Quote-based | Global media publishers |
| 5. Alley | Newsroom speed and ad-tech balance | Quote-based | News publishers and nonprofits |
| 6. Speed Boostr | Shopify-only speed fixes | Quote-based | Shopify merchants needing a fix, not a rebuild |
| 7. Speed Shop | Backend and Rails performance | Quote-based | Backend-heavy SaaS applications |
| 8. Vaimo | Enterprise composable commerce speed | Quote-based | Global multi-storefront retailers |
| 9. Onilab | Magento and BigCommerce speed audits | Quote-based | Mid-market Magento and BigCommerce stores |
| 10. Elogic | Enterprise commerce platform speed | USD $50,000/project | Enterprise consumer electronics and apparel brands |
| 11. Bounteous | Enterprise platform performance | Quote-based | Enterprise digital transformation programs |
| 12. Blue Acorn iCi | Adobe Commerce and Shopify Plus speed | Quote-based | Adobe Commerce and Shopify Plus merchants |
| 13. WP Buffs | White-label WordPress maintenance and speed | Quote-based | Agencies outsourcing WordPress maintenance |
| 14. Bejamas | Jamstack migration for speed | Quote-based | B2B SaaS marketing sites |
| 15. Groove Commerce | Shopify and BigCommerce speed plus accessibility | Quote-based | Mid-market direct-to-consumer retailers |
| 16. Yottaa | Edge-managed third-party tag performance | Quote-based | Retailers with heavy marketing tag stacks |
| 17. Classy Llama | Adobe Commerce integration performance | Quote-based | Mid-market Adobe Commerce merchants |
| 18. Wagento | B2B commerce performance | Quote-based | B2B manufacturers and wholesalers |
| 19. MGT Commerce | Managed Magento hosting and speed | Quote-based | Magento and Adobe Commerce stores needing tuned hosting |
| 20. Creatuity | Magento and Hyvä performance audits | Quote-based | Mid-market Magento specialty retailers |
| 21. Divante | Composable commerce speed architecture | Quote-based | European manufacturers and multi-market retailers |
Frequently Asked Questions
How much revenue does site speed actually move?
Enough to fund the work on most commerce sites. The Deloitte and Google study of retail behaviour found a 0.1-second improvement lifted conversions 8.4% and average order value 9.2%, and cross-industry data shows sites loading in one second converting roughly three times better than sites taking five. Lead-generation benchmarks tell the same story, with average conversion near 40% at a one-second load against about 29% at three seconds. Treat those as direction rather than promises, then measure your own funnel, because the size of the effect depends on how impatient your buyers already are.
Is my site probably failing Core Web Vitals?
There is a good chance on mobile. HTTP Archive data shows about 48% of sites worldwide passing all three Core Web Vitals in 2024, up from 31% in 2022, but the device split is stark: roughly 40% of mobile sites pass against 54% on desktop. Time to First Byte is a common culprit, with only around 42% of mobile sites rated good and 19% poor. Check your own Chrome User Experience report data before commissioning anything, because field data and a lab score can disagree completely.
What does a performance engagement cost?
Only one of the twenty external agencies here publishes a figure, starting around USD $50,000 per project at the enterprise commerce end, and specialist Magento or Adobe Commerce remediation is routinely quoted between $50,000 and $500,000 or more depending on scope. Smaller work behaves differently: a Shopify theme or WordPress speed pass is typically a few thousand dollars, and some providers sell it as a fixed audit plus a fix list. Ask whether the price buys a report, an implementation, or an ongoing performance budget with monitoring.
Audit or ongoing retainer?
Start with an audit, but assume regression. Performance decays every time marketing adds a tag, a designer adds a hero video or a developer ships an untested dependency, which is why the mature pattern pairs a remediation project with performance budgets enforced in continuous integration. If your site changes weekly, a retainer or monitored budget is cheaper than repeating the audit annually. If the site is fairly static, a one-off engagement plus field monitoring is usually enough.
Does platform experience matter more than general skill?
Yes, and it is the main reason this list looks fragmented. Magento and Adobe Commerce bottlenecks are database, indexing, caching and Hyvä-layer problems; Shopify limits you to theme, app and Liquid work with no server access; enterprise WordPress publishing is about object caching, ad tech and editorial workload; a Rails or Django application is a backend profiling exercise. Hire the team that has already fixed your stack under load, and ask to see before-and-after field data rather than a lab screenshot.
Choosing a Website Speed Agency
Insist on field data. Lab scores are a diagnostic, not a result. Ask for real-user monitoring at the start and the end, segmented by device and template, because a green desktop score hides the mobile problem that costs you sales.
Scope by template, not page count. Fixes land on the home page, category, product and landing templates. A proposal priced by pages usually signals a scanner-driven checklist rather than engineering.
Ask who owns the third-party tags. Marketing scripts are frequently the single heaviest cost on a commerce page, and the fix is political as much as technical. A partner willing to argue about tag governance will save you more than one who only compresses images.
Protect the win. Set performance budgets and monitoring so the next release does not undo the work. If you want speed argued alongside the media spend the page has to earn back, see our web development work, read the latest analysis, or book a call.
