Building a SaaS product shouldn’t mean choosing between an unpredictable freelancer and a slow, expensive agency. By Design UK sits deliberately between the two: a UK-based development team offering fixed price SaaS development, AI-accelerated build timelines, and full source code ownership from day one. No hourly billing, no scope creep, no vague retainers — just a defined project, a defined price, and a product you actually own.
We work with founders, startups, and growing UK businesses who need a working SaaS platform without the overhead of hiring an internal engineering team. Every SaaS development engagement starts with a fixed quote based on your specification, so you know the total investment before a single line of code is written.
SaaS builds typically range from £18,000 to £650,000+, depending on complexity, integrations, and the number of user roles or modules involved. A lean MVP with core authentication, billing, and a single toolkit sits at the lower end of that range, while multi-tenant platforms with complex permissioning, third-party integrations, and custom infrastructure sit higher up. If your requirements are closer to ecommerce than a standalone platform, our Shopify build services start from £499 and scale to £18,999 for advanced custom storefronts. Every quote is fixed before work begins, and we’ll tell you honestly which route fits your goals and budget rather than upselling you into the wrong build.
We don’t just talk about SaaS development — we run one. Tackly.co.uk is a live, multi-toolkit SaaS platform designed, built, and operated by By Design UK. It’s real evidence of our technical capability: production infrastructure, real users, ongoing maintenance, and the same AI-accelerated engineering approach we apply to client projects. When you work with us, you’re not trusting a portfolio of screenshots — you’re trusting a team that operates its own SaaS product day in, day out.
Freelancers can be a low-cost route into SaaS development, but reliability is the trade-off: single points of failure, inconsistent availability, and code ownership that’s often unclear or poorly documented. Traditional agencies solve the reliability problem but introduce new ones — slow discovery phases, opaque day-rate pricing that balloons mid-project, and layers of account management between you and the engineers actually writing your product. By Design UK removes both risk profiles. You get a structured UK team, a fixed price agreed upfront, transparent milestones, and complete source code ownership handed over at delivery — not licensed, not held hostage, yours outright.
Because pricing is fixed rather than time-and-materials, you’re incentivised to plan a tight, well-scoped MVP rather than a bloated feature list. We’ll help you prioritise what actually needs to be in version one, and what can follow in a later phase once you’ve validated demand with real users.
Fixed price SaaS development suits founders who need a working product to raise funding, sell to early customers, or replace a fragile prototype with production-grade software. It also suits established businesses building an internal platform or a customer-facing tool who want cost certainty rather than an open-ended agency retainer. If you’re still deciding between a SaaS platform and an ecommerce build, our team can walk you through both paths — get in touch via our contact page and we’ll give you a straight answer, not a sales pitch.
Learn more about how we work, our AI-accelerated process, and the team behind Tackly.co.uk on our about page.
Yes. Full source code ownership transfers to you on project completion — there’s no licensing arrangement or vendor lock-in. This is a core part of our fixed price model.
Timelines vary with scope, but our AI-accelerated development process typically delivers a well-scoped MVP faster than traditional agency timelines. We’ll give you a specific delivery date as part of your fixed quote.
We agree the fixed price against a defined specification. Genuine scope changes are quoted transparently as separate fixed additions, so there’s never a surprise invoice.
Yes. Tackly.co.uk is a live multi-toolkit SaaS platform we designed, built, and continue to operate, demonstrating our real-world technical capability beyond a portfolio.
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