Glossary

Coded Prototype

A coded prototype is working software, built early and quickly, to answer a product question that a design file cannot. Some risks only appear when the product runs. Examples are real amounts of data, AI answers that appear word by word, screens that resize and how a screen reader handles an interaction.

Prototyping
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Coded prototype examples: Benchmark Gensuite and ConnectX

The boundary of what was simulated matters as much as what was shown.

A team might need real code to see how an AI answer appears word by word, or how a layout reshapes on a phone. The data could be real while sign-in and error responses are pretend. Writing that down tells reviewers which choices the prototype can support.

Turning a coded prototype into production software is a separate step. Prototype hardening is the engineering needed before real users rely on it. Design engineering links the product choice to the behaviour in code.

See Coded Prototyping for what Tcules offers. The examples below show what a coded demonstration can establish.

A coded prototype earns its place when the uncertainty is about behaviour that static screens show poorly. For ConnectX, Tcules used a coded workspace demonstration to make an AI-native product direction concrete enough to review before live integration.

For Benchmark Gensuite, coded prototypes of shared interface patterns and a three-view scope selector let the team review interaction behaviour and feasibility before wider build. An engineering reviewer raised a build question while the team could still act on it.

A good prototype states what it tests and what it simulates, because running code can look more finished than it is.

Coded prototype vs Figma prototype: what each can show

A Figma prototype links design frames with clicks and transitions. A coded prototype runs as software, so it can respond to real data, typing, resizing and assistive technology. Each suits a different question.

	Figma prototype	Coded prototype
Best for	Flow, layout, wording and early reactions	Behaviour that depends on data, timing, input or the device
Runs as	Linked design frames	Software in a browser or on a device
Data	Sample content placed by the designer	Real or realistic data, in realistic amounts
Input	Clicks, hover, drag and key triggers between frames	Real typing, keyboard navigation, resizing and screen readers
Effort to change	Quick to rework	More effort, so it is aimed at one question

The benefits of a coded prototype follow from that table. Engineers can try the design in the browser. Problems with data, input or feasibility surface while there is still time to change course. Reviewers judge behaviour they can use, which a picture of it can only suggest.

Coded prototype vs production code: what changes before release

A coded prototype is built to test one question, often with sample data or stand-in services. What has to change before release is set out under prototype hardening.

Coded prototype FAQs

How is a coded prototype different from a Figma prototype?

A Figma prototype links design frames, which suits flow, layout and wording. A coded prototype is working software, so it can show real data volumes, streaming AI answers, resizing and keyboard or screen reader use. Teams often use both, each for the question it answers best.

When should a team build a coded prototype?

Build one when the open question is about behaviour a design file shows poorly. Examples are large amounts of data, an AI answer that arrives word by word, or drag and drop. If the question is about flow or wording, a design prototype is usually enough.

Is a coded prototype production code?

Usually it is a test piece, built to answer one question with sample data, stand-in services or simplified states. Some of its code can carry forward, but it needs prototype hardening before real users rely on it.

What are the benefits of a coded prototype?

It lets people use the behaviour instead of imagining it, and lets engineers judge feasibility in the browser. Problems with data, input or performance show up early, when changing course still costs little.

When to build a coded prototype

Some product questions can only be answered in running code. Build one when the doubt is about behaviour: how much data a screen must hold, how an AI answer arrives or how a keyboard user moves through a task. Questions about flow, layout or wording are usually cheaper to answer in a design file.

That line is moving. AI tools now turn a sketch or a sentence into running code, so teams reach a coded prototype earlier than they used to. The skill shifts to choosing the question it should answer and reading what it shows.

See Coded Prototyping