System architecture diagram
Definition
A system architecture diagram is a visual representation of a software system's major components — services, databases, queues, external APIs — and the data and control flows between them.
System architecture diagrams don't follow a single formal standard the way UML diagrams do. Instead, they use a common-sense visual vocabulary: boxes for services and data stores, lines and arrows for connections, labels for protocols and data formats. The C4 model (Context, Container, Component, Code) provides one structured approach; AWS/Azure/GCP have their own icon sets; many teams just draw boxes and arrows.
Architecture diagrams serve several purposes. During design, they make architectural decisions concrete and debatable — you can't argue about a microservices split until you draw where the service boundary goes. During onboarding, they give new engineers a mental model of the system in minutes. During incidents, they help responders trace the path of a failure.
The most common whiteboard scenario: a team gathers to design a new system or a major change, someone draws a box for each major component, arrows for dependencies, and labels for the data that flows between them. That sketch becomes the reference point for the discussion. BoardSnap AI reads those boxes, arrows, and labels and produces a component-by-component summary — a head start on the architecture decision record or the wiki page that should follow the session.
Examples
- Three-tier web app: Browser → Load balancer → App servers → PostgreSQL + Redis
- Event-driven architecture: API → Kafka topic → Consumer services → S3 + Analytics DB
- Mobile backend: iOS app → API Gateway → Lambda functions → DynamoDB + S3, with Cognito for auth
- Microservices: API gateway routing to Auth, Product, Inventory, and Order services, each with their own database
Snap a system architecture diagram. Ship its actions.
BoardSnap turns any whiteboard — including this one — into a summary and action plan.