Architecture principles
On this page 9 topics
Overview
Topics
- Standardization
- interoperability
- security
- evolvability
Learn first
2.5 h of practice (estimate)
Learning outcomes
- Write architecture principles with statement, rationale, and implications.
- Apply principles for standardization, interoperability, security, and evolvability to design decisions.
- Resolve conflicts between principles explicitly.
- Use principles to evaluate options and justify exceptions.
Lessons
Lab and exercises
Lab
ARC-007-LAB1 · Larkspur principles
Outcomes: 1–4 · Time: ~2.5 h
- Gather strategy and constraint inputs from the case.
- Draft eight to ten principles, each with statement, rationale, and implications.
- Review with role-played IT leadership; revise.
- Apply each principle to one real Larkspur decision and record the result.
- Record one principle conflict and its resolution, plus the exception process.
Acceptance: at least one principle changes a decision; one conflict resolved on record.
Exercises (case-based; six exercises)
| ID | Outcome | Task |
|---|---|---|
| ARC-007-EX01 | 1 | Rewrite three platitudes ("use best practices", "be scalable", "keep it simple") as testable principles with implications. |
| ARC-007-EX02 | 1 | Write one full principle (statement, rationale, implications) on interoperability for Larkspur. |
| ARC-007-EX03 | 2 | Use a standardization principle and an evolvability principle to evaluate two API options for carriers. |
| ARC-007-EX04 | 2 | Apply a security principle to a proposal to share the customer database directly with the CRM. |
| ARC-007-EX05 | 3 | Standardization says one event platform; store systems only support file transfer. Write the conflict record and decision. |
| ARC-007-EX06 | 4 | A team requests an exception to use a niche payment SDK. Write an assessment against the principles and a time-limited exception. |
Show solutions
- EX01 Examples: "Customer data is changed only through its owning service"; "Every service has a stated load target and is tested at 2x"; "Remove a component or interface for each one added, unless a decision record says why not".
- EX02 Statement: systems integrate through published, versioned interfaces. Rationale: partners and teams change independently. Implications: API governance, no direct database access, versioning policy.
- EX03 Prefer the option using the standard API style unless a carrier cannot support it; if exceptions, wrap them behind an adapter to preserve evolvability.
- EX04 Direct database sharing violates the principle of access via owned interfaces and widens attack surface; propose an API or event feed.
- EX05 Decision: exception for stores via a file gateway that converts to events, owner IT director, review in 12 months.
- EX06 Assess fit, maintenance, and security; grant a time-limited exception with an owner, conditions (isolate behind an interface), and an exit date.
Workplace evidence: principles you wrote that were cited in real design decisions.
Quiz
Outcomes: O1 writing principles · O2 applying principle families · O3 resolving conflicts · O4 evaluating options and exceptions.
A self-check for you: nothing is graded, saved or sent anywhere. Choose an answer, then check it. You can try again as often as you like.
Practical part
Principles review of the lab set and exercises ARC-007-EX01 to EX06. Pass: quiz at least 8/10, at least five of six exercises correct, and a principle set where at least one principle changed a decision and one conflict is resolved on record.
Common mistakes
Platitudes ("use best practices"); principles without implications.
Assessment
Principles review.
Workplace evidence
Principles you wrote that were cited in real design decisions.
Career relevance
Review boards (ARC-035).