In many modern software teams, a phrase appears frequently: "Check Figma — that's the source of truth." The statement usually reflects good intentions. Teams want a shared reference for how the system should behave, and a centralized design file seems like a natural place to store that information. But when Figma becomes the source of truth for a software project, the delivery process begins to drift. Design tools are excellent at visualizing interfaces — they are not designed to define systems. Understanding this distinction is critical for predictable delivery.
What Design Tools Are Good At
Figma and similar design tools are extremely effective for certain tasks. They allow teams to visualize interface layouts, explore interaction patterns, create reusable design components, and communicate user experience concepts. For user experience design, these capabilities are invaluable — they allow teams to iterate quickly and explore solutions before implementation begins. However, visualization is only one dimension of a software system.
What a Software System Actually Contains
A working software system includes far more than interface layouts. It contains domain entities and relationships, business rules, integration behaviors, security constraints, content structures, validation rules, error handling logic, and operational monitoring. Most of these elements cannot be represented effectively inside a design file. When teams treat Figma as the system definition, these critical aspects of the system become implicit rather than explicit — developers are forced to infer behavior from visual layouts, and that is where delivery friction begins.
The Hidden Cost of Design-Centric Truth
When design files become the primary reference for the system, several predictable problems appear. First, behavioral gaps emerge: designs often show the ideal state of a screen but rarely describe what happens when data is missing, when validation fails, or when external systems respond slowly. Second, domain models become invisible, as the relationships between users, orders, content types, and permissions are rarely defined clearly in interface design. Third, business rules remain undocumented, existing only in conversations or stakeholder expectations rather than explicit specifications. As development progresses, engineers must fill these gaps themselves, and each interpretation introduces a small deviation from the intended behavior that accumulates over time.
Where Design Fits in the Artifact Chain
Design artifacts are an essential part of software delivery, but they represent only one link in a larger chain:
Design files appear in the middle of this chain. They translate capabilities and journeys into interface behavior, showing how the system should appear and how users interact with it. But design artifacts depend on earlier artifacts for context and must be translated into later artifacts for implementation. Treating design as the source of truth breaks this chain.
The Role of the Component Inventory
One of the most effective ways to stabilize the relationship between design and development is through a component inventory — a list of every reusable interface element required by the system, such as hero blocks, cards, search components, navigation modules, form patterns, and dashboard widgets. Each component becomes a unit of behavior that can be designed, specified, and implemented consistently. Design tools visualize these components, but the component inventory defines them. This distinction prevents the system definition from becoming trapped inside a design file.
Shared Truth Across Artifacts
A healthy delivery process distributes the system definition across multiple artifacts, each expressing a different dimension of the system: strategy artifacts define capabilities, design artifacts express user experience, specification artifacts define behavior, and code implements the system. When these artifacts remain connected, the project maintains a coherent definition of the system. No single tool becomes the source of truth — instead, the truth of the system emerges from the consistency of the artifact chain.
Design Is a Representation, Not the System
Figma is an extraordinary tool for representing interfaces, but representation is not definition. A design file shows how the system should appear and behave visually — it cannot capture the full complexity of the system that engineers must build. Treating design tools as the source of truth shifts too much responsibility onto a single artifact. Software delivery becomes more reliable when the system definition is distributed across structured artifacts that together describe the system completely. Design remains a critical part of that system. It simply should not be mistaken for the system itself.