Architecture Principles Document
A set of guiding statements that inform and constrain architectural decisions across a programme or organisation, ensuring consistency and alignment with strategic objectives.
Purpose
Architecture principles provide a decision-making framework that ensures consistency across teams and projects. They reduce debate on recurring topics, accelerate decision-making, and ensure alignment with organisational strategy and values.
When to Use
Define architecture principles at the programme or organisation level before projects begin. Reference them in ADRs and architecture reviews. Review and update annually or when strategy changes significantly.
How to Build
Start by reviewing existing organisational principles, strategies, and policies. Architecture principles should align with and support these higher-level directives.
For each principle, define: a clear name, a statement of the principle, the rationale (why this principle exists), and the implications (what this means in practice for teams making decisions).
Keep the set small and focused — 8-15 principles is typical. Too many principles dilute their impact and create conflicts.
Validate principles against recent architectural decisions — would they have guided teams to the right outcome? If not, refine them.
Get buy-in from senior technical leadership and ensure principles are communicated widely and referenced in architecture reviews.
Tips
- Each principle should be actionable — it should help someone make a decision.
- Include implications for each principle — abstract statements without practical guidance are ignored.
- Principles should be stable but not immutable — review them annually.
- Avoid principles that are so obvious they add no value (e.g., 'build secure systems').
- Reference government principles (Technology Code of Practice) to show alignment.
Common Mistakes
- Having too many principles that conflict with each other.
- Writing principles so vaguely that they cannot guide actual decisions.
- Not including implications, leaving teams to interpret principles differently.
- Setting principles and never referencing them in architecture reviews or ADRs.
- Not updating principles when organisational strategy changes.
Government Context
In UK government, architecture principles should align with the Technology Code of Practice, the GDS Service Standard, and the Government Digital Strategy. Common government principles include: use cloud first, use open standards, share and reuse, design for users, and make things accessible. Departments often extend these with domain-specific principles. CDDO publishes cross-government architecture principles that should be referenced.