The document that turns a beautiful design into a buildable brief.
Most technical specifications are written by the developers being paid to build the product. Ours are written first, by the side that has to make sure what gets built is actually what you designed.
Design files show what the product looks like. Architecture shows what it has to do.
Founders arrive at the development briefing stage with screens. Sometimes hundreds of them. Beautiful, considered, signed off by everyone who needed to sign them off. And then the conversation with developers starts, and within an hour it becomes clear that the screens, on their own, are not enough to quote against. The team is being asked to estimate cost and timeline against a product whose technical shape has never actually been defined.
App architecture design is the work that closes that gap. It is the design-side equivalent of a software specification, written before a development team is hired rather than after. It defines platform decisions, data flows, API requirements, third-party integrations, authentication, offline behaviour, and performance expectations. It tells a development team exactly what to build, why each decision was made, and what constraints they are working within.
This work is not the same as the internal architecture documentation a development team produces once they start. That document is written for engineers, by engineers, in the language of the codebase they have chosen. The architecture document WAA produces is written for the client, in the language of the product, and exists so that the development quote, the build itself, and the finished result all match the design intent.
A Figma file is a description of an interface. It is not a description of a system. The two are related, and a good design implies a great deal about what the system has to do, but the implications need to be made explicit before a development team is asked to evaluate technical feasibility and put a number on it. When development starts without a proper specification, the missing information gets filled in by whoever happens to be writing the code that week. That is where a product loses its shape.
There is also a question of route. Native iOS, native Android, cross-platform, or a progressive web app are different ways to build the same product, each with very different cost, timeline, and experience implications. That decision belongs in the architecture document, made on the basis of what the product needs to do, not on the basis of which framework the chosen development agency happens to prefer.
A development quote without a specification is a guess. A clever guess, sometimes. Still a guess.
Ask three development agencies to quote on the same set of design files and you will get three wildly different numbers. Not because one is more expensive than another. Because each one is quoting against a different set of assumptions about what the product actually has to do. One has assumed a simple authentication flow. Another has assumed a complex one. A third has assumed offline support that no one ever asked for. None of them are wrong, exactly. None of them are right either.
The architecture document is what makes those quotes comparable. When every agency is quoting against the same specification, the differences in their numbers reflect the differences in their work, not the differences in their assumptions. That alone is usually worth more than the cost of the engagement.
The other reason matters more. Assumptions that get resolved mid-build cost a great deal more than assumptions resolved before the build begins. A decision about how user data is structured, taken in week two of development, costs a day of conversation. The same decision, taken in month four because something downstream has stopped working, costs weeks of rework and a difficult invoice. The cheapest time to make a technology decision is before anyone has written code against the previous one. Choosing the right tech stack is not a job for the second sprint.
Without an architecture document, the development team will make these decisions for you. They have to. The code cannot wait for permission. The decisions get made on the basis of what is easiest to ship that week, what the lead engineer is familiar with, what the chosen framework supports by default. None of those criteria are bad. They are simply not the same as making the decision on the basis of what the product needs and what the user experience demands.
Most of the reasons app development projects struggle trace back to this single gap. Not to bad developers, not to bad designers, but to the absence of the document that should have sat between the two. That gap is what this engagement is built to close.
Five layers. Each one settled before the development team is briefed, not during.
The work is design-informed throughout. The specification reflects the product you designed, not the technical preferences of whichever team ends up writing the code.
Platform and technology recommendations
iOS, Android, cross-platform, or progressive web app. Each choice carries implications for the user experience, the cost of build, and the long-term maintainability of the product. WAA makes the recommendation based on what the product needs to do for the user it is being designed for, not on what is easiest to build with the tools a particular agency already uses.
Data architecture and flow mapping
How information moves through the product. What data is collected, where it is stored, how it is retrieved, and what the privacy and compliance implications are. This is the layer most design agencies do not touch, and the layer most development teams define too late. Defining it at the architecture stage prevents most of the costly rework that happens further down.
API and integration specification
Third-party services, payment gateways, authentication systems, mapping tools, and notification services all need to be specified before development begins. WAA documents what is required, what each integration costs, and what the technical constraints are. The development team starts the conversation with a list, not a discovery exercise.
Performance and scalability requirements
What the product needs to do under load. How it should behave on slow connections. What offline functionality is required, and what the experience looks like when the connection drops mid-session. These requirements shape architectural decisions that are very difficult to reverse once the product is in build.
Security and compliance considerations
GDPR, data handling, authentication security, and any industry-specific regulatory requirements documented at the architecture stage rather than discovered during development. The cost of building compliance in from the start is a small fraction of the cost of bolting it on once the product exists.
Ready to get your app properly specified before development starts?
Send us the design work and we will come back with a clear scope.
A complete technical specification document. Written for you, ready for them.
Every output is design-informed and client-facing. The development team you brief afterwards will have everything they need to quote and to build without having to invent the missing pieces themselves.
Four situations where this work is the missing piece.
Architecture design is most often commissioned on its own when the design work has already been done, or when an existing product needs rebuilding properly. The four scenarios below are the ones we see most.
You have finished UX and UI from another agency or an in-house team. You need a development-ready specification before you brief agencies or hire developers. The screens exist. The brief that goes with them does not.
You have an existing app and a clear sense that it needs rebuilding. Before commissioning new design or development work, the technical architecture needs to be defined so the rebuild solves the right problems rather than recreating the old ones.
You need to present a technically credible product brief to an internal development team or to procurement. The specification gives the conversation a shared reference point, and gives the people receiving it something they can actually plan against.
You have asked three agencies for development quotes and received three numbers that bear no relation to each other. A proper specification is what makes those quotes comparable. You stop choosing between estimates and start choosing between teams.
Not sure if you need a standalone architecture engagement?
A short call is usually enough to work out whether this is the right next step.
The questions founders ask us most often.
Do I need architecture design if I already have UX and UI?
Yes. Design files show what the product looks like and how it flows. Architecture specification shows what it has to do technically in order to deliver that experience. Development teams need both. Without the second one, they will define the technical shape of the product themselves, which is the moment your design starts to drift away from what gets built.
Can WAA do architecture design without UX and UI?
Yes. If the design has been completed elsewhere, we review the existing work and produce the architecture specification from there. We need access to the design files, any existing brand and strategy documentation, and a conversation with whoever owns the product vision. From there, the engagement runs the same way.
How long does a technical architecture engagement take?
Typically four to eight weeks from kick-off to final document, depending on product complexity. A focused single-platform product with a small set of integrations sits at the lower end. A multi-platform product with significant third-party dependencies, offline requirements, or regulated data handling sits at the higher end. We give a firm range after the first scoping conversation.
How does architecture design fit with WAA’s other services?
The natural sequence runs strategy, then UX, then UI, then architecture. Strategy is covered by App Planning & Strategy, and the design layer is covered by App UX Design. Architecture sits at the end of that sequence and turns everything that came before it into a specification a development team can build against. The services can be commissioned as a complete pre-development engagement or as standalone pieces.
Three ways to start the conversation.
Whether you want to send us the design files and talk through the work, talk it through first, or simply understand what an engagement costs, pick the path that fits where you are.
Tell us about your project.
Share what you have, what stage you are at, and what you need a specification for. We will come back to you with a scoped response and a clear next step.
Send project details →Book a discovery call.
Thirty minutes to talk through where you are and what you need. If a standalone architecture engagement is the right next step, we will tell you. If it is not, we will tell you that too.
Book a call →See what it costs.
Indicative pricing for architecture engagements and the rest of the pre-development services, with the variables that move the number up or down.
See pricing →