White Label WordPress Development for Agencies
The overflow developer your clients never hear about.
White-label builds, integrations, paid media and AI automation for agencies that sell websites but don't carry a senior developer. I'm Matt: one reliable person, your brand on everything, and you'll always be talking to me.
Book a 20-minute call →
MATT BUCKLEY · CELLSIORFormer Buddhist monk. Ask on the call, it's a better story than most case studies.
Your pipeline sells websites. Your payroll doesn't build them.
Every agency between five and fifteen people hits the same wall. The strategy is yours, the client is yours, the deadline is yours, and the build lands on whichever freelancer answered the phone this month. One does the theme. Another does the integrations. A third runs the ads. None of them have met, and all of them need chasing.
And every agency owner carries the same scar: the freelancer who went quiet the week before launch. Or the one who found your client's email address. I built this service around making both impossible.
Call it white label web development, call it outsourcing your WordPress builds. The arrangement is simpler than the name: you sell it, I build it, your client never knows I exist.
You've lived the first half. The fix is what you're hiring.
One person, whole job.
BuildCustom WordPress, real code
Bespoke themes and plugins, ACF content models, multisite, WooCommerce. Clean code your next developer can read. No page-builder bloat, unless your stack demands it.
SignatureInteractive 3D & WebGL
Product viewers, configurators and hero sections your competitors can't quote for. The pieces that win pitches. See them below.
RescuePerformance & Core Web Vitals
Slow builds brought into the green, with before and after reports your client can read. My own custom stack scores 95+ on Lighthouse.
SearchSEO built in, not bolted on
Technical SEO, schema, clean migrations, SEO-led information architecture. Sites that arrive ranking-ready, plus on-page and content strategy when you need it.
GrowPaid media that converts
Google, Meta and LinkedIn Ads run white-label: campaign builds, landing page strategy, A/B testing. Tripled conversion rates on a five-figure monthly account.
MeasureAnalytics & reporting
GA4 and server-side tracking implemented properly, conversion events at template level, and Looker Studio dashboards you can put your own logo on.
ConnectIntegrations
Payments and webhooks, third-party APIs, CRM, booking systems, email platforms. The plumbing between your client's tools, done once and done right.
EdgeAI automation
Production AI systems, not prototypes: content pipelines, internal tools, reporting automations your agency can resell under its own name.
Don't take my word for it. It's running right now.
cellsior.comParticle hero, hand-coded WordPress, 95+ Lighthouse
cellsior.com/lab3D product configurator, live colour and material switching
cellsior.com/labWebGL laser cutter, the kind of piece that wins pitches
Everything above runs on the same custom stack I'd use for your clients. More experiments live at cellsior.com/lab. Agency client work stays confidential, which is why you're looking at my own sites instead.
Built to be invisible.
NDA first
Standard, signed before we talk detail. Your client list is safe.
You brief me
Scope and a fixed quote up front. If a deadline is at risk you hear it early, never the week of.
I build under your brand
Files, staging, comms, all yours. As much or as little client contact as you want, including none.
You present it
Your name on the work. Nothing I build for you ever appears in my portfolio.
Six years of being exactly this, for somebody else.
For the last six years I've been the developer behind a European agency's largest international account, a global industrial manufacturer, building and running dozens of production WordPress sites across five technology verticals. The person their project managers hand things to when it has to be right. Agency and client under NDA, which is rather the point. References available in a call.
The stack is mine, from scratch. A complete custom WordPress theme and plugin suite; it runs cellsior.com at 95+ Lighthouse.
End-to-end delivery, named: Penny's Ark (charity), full site, payment integration with webhooks, and a third-party API performance fix.
The craft is public: live WebGL and 3D experiments at cellsior.com/lab.
AI in production: research engines, outreach systems, reporting tools, built and running, not slideware.
My afternoon is your morning.
I'm a British developer based in Thailand, six hours ahead. By your 9am I've already done half a day on your project, and I'm at my desk until your late afternoon. Urgent fixes land before your client wakes up. Six years of delivering for European clients on exactly this rhythm.
The honest answers.
Why not just hire in-house?
If you have forty hours of dev work every week, you should. Most agencies your size have lumpy demand: three builds one month, none the next. I'm senior capacity you switch on per project, with no salary, notice period or quiet months.
Will you ever speak to our client?
Only if you ask me to, and then as your team. Plenty of agencies never introduce me at all. Either way your client's contact details never enter my systems, and the work never appears in my portfolio.
What do you actually cover?
WordPress first: custom themes, ACF, WooCommerce, multisite, plus Shopify and the integration layer around everything. On the marketing side: technical SEO, Google, Meta and LinkedIn Ads, GA4 and server-side tracking, Looker Studio reporting. If your team works in a page builder, I can work in it too; I'd just rather show you the faster way.
How do you charge?
A fixed quote per project, or a simple day rate for ongoing cover. Agreed up front, no surprises on the invoice. White-label means you set your own margin on top.
How fast can you start?
Usually within the week. Tell me the deadline on the call and you'll get a straight answer, not an optimistic one.
Got a build you need off your plate?
Twenty minutes. Bring the project that's keeping you up; I'll tell you honestly what it needs, what it costs and when it can land.
Book the call → Prefer email? [email protected] · NDA available before any detail is shared