Technical Constraints
Existing estate, skills, licences and platforms as inputs rather than obstacles.
3 to work through
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A quick-commerce platform's architecture is bounded by things that are not software: store leases, courier supply, road conditions, and the physical time to pick items off a shelf. How should such constraints enter the design?
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A retailer's website must show whether an item is available in a nearby store. Store systems are occasionally offline and physical counts drift from recorded counts. How should availability be modelled?
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An observability platform lets customers attach arbitrary tags to metrics. One customer adds a tag containing a request identifier. What would you change about the system's constraints, and why is "tell the customer not to do that" an insufficient answer?
2 min answer
3 terms in this topic
Assumption Register
The record of the numeric assumptions a design was sized against, monitored so the architecture announces when its own premises expire.
conceptTechnical Constraints
The existing estate, skills, licences, contracts and platforms that bound the solution space — inputs to the design, not obstacles to it.
conceptVendor Lock-In
The cost of switching away from a provider, treated as a quantity to be managed deliberately rather than a condition to be avoided absolutely.
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.
Quality Attributes
Availability, latency, throughput, security, cost — expressed as testable scenarios.
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.
Architecture Roles
Solution, enterprise, domain and platform architecture, and where each is accountable.
Reference Models
Shared conceptual frames — layering, tiers, viewpoints — and their limits.