Quality Attributes
Availability, latency, throughput, security, cost — expressed as testable scenarios.
6 to work through
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beginner
A developer-tools team writes "the workspace must be fast and reliable" into a design document. What is wrong with that, and what should it say instead?
1 min answer -
intermediate Multiple choice
A product manager asks to tighten the API latency target from p99 300 ms to p99 100 ms. What should the architect do before agreeing?
2 min answer -
intermediate
A project is three sprints from launch and no non-functional requirements were ever written down. What do you do?
1 min answer -
intermediate
What happens if a global content delivery platform sets a quality-attribute target of "cache hit ratio above 95%" and simultaneously "content updates visible worldwide within 5 seconds"? Explain the conflict and how it is normally resolved.
2 min answer -
advanced
A streaming platform is adding scheduled live events to a catalogue service that has always served on-demand content. Which quality attributes change, and why is this not "the same system with more traffic"?
2 min answer -
advanced
You are starting a greenfield platform. How do you establish what the architecture must satisfy before designing anything?
2 min answer
2 terms in this topic
Quality Attribute Scenario
A six-part template that turns a vague quality goal into something you can measure and argue about.
practiceUtility Tree
A structured decomposition of quality attributes into concrete, prioritised scenarios, used to focus architectural analysis on what actually matters.
Neighbouring topics
Architecture Fundamentals
General material on what solution architecture is and what an architect is accountable for.
Requirements to Constraints
Turning stated requirements into the constraints that actually bound a design.
Functional vs Non-Functional
Behaviour versus quality of behaviour, and why only the second constrains structure.
Architectural Drivers
The small subset of requirements whose change would force the structure to change.
Architecture Principles
Durable agreed rules that rule options out, stated with rationale and implications.
Coupling
How much one component must know about, or change alongside, another.
Cohesion
Whether the things inside a boundary belong together and change for the same reason.
Modularity
Composing a system from parts that can be understood and replaced independently.
Separation of Concerns
Organising so that a change to one concern touches one place.
Abstraction & Encapsulation
Hiding mechanism behind contract, and protecting invariants by owning state.
Architecture Styles
System-level organising shapes, and how they differ from problem-level patterns.
Evolutionary Architecture
Designing for guided incremental change rather than for correctness on day one.
Fitness Functions
Automated checks that an architectural characteristic still holds.
Architecture Documentation
What to write down, at what altitude, and what nobody will ever read.
Conway's Law
Systems mirroring the communication structure of the organisation that builds them.
Trade-off Fundamentals
Why every architecture is a set of purchases, and how to state what you gave up.
Technical Constraints
Existing estate, skills, licences and platforms as inputs rather than obstacles.
Architecture Roles
Solution, enterprise, domain and platform architecture, and where each is accountable.
Reference Models
Shared conceptual frames — layering, tiers, viewpoints — and their limits.