Great software starts with great design. Before a single line of production code is written, the decisions made at the UX and UI prototyping stage determine whether your SaaS platform will delight users or frustrate them into cancelling. At By Design UK, we treat design not as a cosmetic layer but as a structural discipline — one that shapes architecture, reduces development risk, and accelerates your route to market.
We are a UK-based software development agency positioned deliberately between the freelancer market and the traditional agency world. Our SaaS design and prototyping service is woven directly into our end-to-end SaaS development process, meaning the design team and the engineering team are the same conversation, not two separate invoices.
SaaS UX/UI design is far broader than choosing a colour palette. Our process covers user research, information architecture, user journey mapping, wireframing, interactive prototyping, and high-fidelity UI design — all validated against real user behaviour before development begins. This approach catches expensive assumptions early and gives stakeholders a tangible, clickable product to test and approve before any build cost is committed.
Our prototypes are built to communicate precisely with developers, using component libraries, design tokens, and documented interaction states. Because we build what we design in-house, there is no translation loss between the design file and the finished product. You receive full source code ownership from day one — your prototype assets, your design system, your platform.
When design is embedded within a full SaaS build, it forms part of our fixed-price project model. Our SaaS development engagements range from £18,000 for an MVP through to £650,000 and beyond for complex, multi-tenant enterprise platforms. The design and prototyping phase is scoped transparently at the outset — no hourly surprises, no scope creep disguised as change requests.
For teams who already have a technical partner but need design leadership, we can scope a standalone design and prototyping engagement. Speak to us via our contact page to discuss what your project requires and receive a fixed-price proposal within five working days.
Once your platform is live, our SaaS support plans from £797 per month keep your product evolving — covering UI iterations, performance monitoring, and ongoing feature design as your user base grows.
The UK market for SaaS design sits between two uncomfortable extremes. Freelance designers often carry genuine talent but limited accountability — projects stall, handovers are incomplete, and intellectual property ownership is frequently ambiguous. At the other end, traditional agencies deliver polished proposals and lengthy timelines, with pricing that is rarely fixed and processes that keep clients at arm’s length from their own product.
By Design UK was built to close that gap. We offer the responsiveness and personal accountability of a specialist team with the process rigour and technical depth of a full agency. Our pricing is fixed, our timelines are honest, and you own everything we build — source code, design files, and documentation included. There are no lock-in contracts and no opaque retainer structures.
We do not only talk about SaaS design — we build and operate our own. Tackly.co.uk is a live, multi-toolkit SaaS platform that our team designed, prototyped, built, and continues to maintain. It demonstrates our end-to-end capability: from early UX research and interactive prototyping through to a production-grade platform serving real users. When you work with By Design UK, you are working with a team that has genuine skin in the SaaS game, not just a portfolio of client screenshots.
Our experience extends across ecommerce and SaaS — if your project sits at that intersection, explore our Shopify development services for context on how we approach commerce-facing builds alongside platform products.
Yes. While our most efficient model is design embedded within a full SaaS build, we can scope standalone UX research, prototyping, or UI design engagements. Contact us with your requirements and we will provide a fixed-price proposal tailored to your stage of development.
You do. Full ownership of all design assets, prototype files, design systems, and source code transfers to you upon project completion. There are no licensing restrictions or agency lock-in on the work we produce for you.
For most SaaS MVP projects, the discovery, wireframing, and interactive prototype phase runs between three and six weeks depending on product complexity and stakeholder availability. This phase is scoped and priced transparently before any work begins.
Yes. All UI design work is produced to WCAG 2.1 AA accessibility guidelines as a baseline and follows a mobile-first responsive approach. Accessibility is not an add-on — it is built into our design process from the first wireframe.
Image via Pixabay
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