Next.js and Sanity Development Retainer
Guaranteed availability to an experienced Next.js and Sanity developer. No hiring, no overhead, just consistent, expert work every single month.
Launch day 
is usually the last day a website gets real attention. New pages stop shipping. Performance quietly drifts. Accessibility gets forgotten until it's a problem. And while all of that happens, competitors keep shipping — new campaigns, new content, new features and a site that's obviously being looked after.
The pace has changed. AI means competitors can turn around new ideas, campaigns and content faster than ever — staying ahead now takes the same relentless, ongoing effort, not a one-off push every year or two.
That's the gap this retainer fills.
A couple of spots open each month for agencies who need an extra pair of trusted hands on Next.js 
and Sanity 
builds, or businesses who want a developer working alongside their marketing team — building new features, pages and sections for upcoming campaigns, while also continuously improving the foundations of the website, technical SEO, accessibility and performance.
Think of it as having an experienced developer on your team, without the overhead of hiring one. Someone who already knows your codebase, understands how your site needs to perform, knows what the business is actually trying to achieve, and is genuinely invested in the outcomes — not just getting paid and moving on to the next client.
A dedicated Next.js and Sanity developer, ready when you are
Next.js and Sanity, nothing else
I don't do a bit of everything. I specialise in Next.js and Sanity CMS — which means from day one of your retainer, I'm not learning on your time. Every day you've secured goes toward building, not figuring out.
That urgent thing done by lunchtime
Urgent request in the morning? Fixed and deployed by the afternoon. No scrambling to find a developer, no onboarding, no delays. You want someone already available, already on it. That's what the retainer gives you.
It gets better over time
The longer we work together, the more I work like part of your team. I know your codebase, your standards and where you're trying to get to which means faster turnarounds and more time spent working towards your goals.
Every decision made with your business in mind
I'm not in and out. I'm here next month and the month after. So I don't cut corners that will hurt your website, introduce patterns that don't scale or make decisions I won't have to stand by.
Retainer Calculator
Choose how many days you need each week (minimum 1 day per week commitment). Cancel anytime with 30 days notice.
How many days per week do you need?
Billed every 4 weeks
Day rate
8 hours is a day
Retainer includes:
- Hands-on development execution -
44 days per month. - Technical SEO, Accessibility & Performance.
- Private Slack channel.
- Monthly planning sessions.
“James has been incredible to work with. Beyond being a solid developer he's also highly responsive and has a great attitude. Highly recommend and we'll be working with him in the future.”
Brett Rutledge
Chief Growth Officer, SitePartners
Your Questions, Answered.
A retainer secures a set number of days each month, giving you priority access to a Next.js and Sanity developer who already understands your codebase, standards, and objectives. The result is faster turnarounds and more time spent on work that actually moves the needle.
Each month covers a set number of scoped days (minimum 4 days, or 1 day per week) dedicated to your website. This can include building new pages and sections for upcoming campaigns, technical SEO and AI discovery improvements, accessibility fixes, and performance optimisation, whichever combination matters most for your site that month. Every month starts with a planning session to agree the exact deliverables, so you know what you're getting upfront.
A retainer makes sense if your website plays a central role in generating leads or customers. Treating it as something continuously improved, rather than "finished" at launch, means new pages, sections and functionality for upcoming campaigns and ongoing technical SEO, AI discovery, CRO and performance work that directly improves conversion. It's also a strong fit if you're an agency that needs an extra pair of hands on a recurring basis.
If you're unsure how much ongoing work you'll need, starting with the minimum (1 day a week) and adjusting from there is the sensible approach.
It's not the right fit for a one-off build with no ongoing changes expected, a fixed-price project makes more sense in that case.
If something urgent comes up, I aim to respond within 1 hour (Monday-Sunday 8am-8pm GMT), and can typically slot in same-day or next-day fixes depending on severity. Since I already know your codebase, urgent issues get resolved faster than starting from scratch with someone unfamiliar with the website.
No, retainer days are reserved, not banked. When you book a retainer slot, that time is blocked out specifically for you, which means I'm turning away other work to guarantee it's available when you need it. This is why the planning session at the start of each month is important, by agreeing exactly what's getting done in advance, we make sure the full allocation gets used productively.
If something comes up that goes beyond your agreed days for the month, there are two options: add extra days at my standard day rate (£360), billed alongside your next invoice, or hold the work over and prioritise it in the following month's planning session. Which makes more sense depends on how urgent the extra work is.
Either way, nothing gets added without agreeing it with you first — you'll never see extra days on an invoice you haven't already approved.
If the scope hasn't changed and something I estimated would take a day doesn't quite get finished, I'll cover that myself. That's on me for the estimate, not something you're billed for.
The one distinction that matters here is scope. If the task grows beyond what was originally agreed — new requirements or a change of direction — that's treated as additional scope and there would be an extra cost for that, but we'd discuss and agree it together before any work starts.
Yes, the retainer runs on a 30-day notice period, so you can pause or cancel at any time by giving 30 days' notice.
Since retainer days are billed upfront and reserved specifically for you, the current month's invoice isn't refundable once the period has started, but nothing further is billed once your notice period ends.
Looking for a reliable Next.js and Sanity developer?
From custom builds to ongoing support, I'm here to help.