The Architecture Review Process: From Proposal to Approval

The Architecture Decision That Haunts You

Your senior engineer proposes migrating from monolith to microservices. It's a bold move—could unlock velocity or tank the team for 6 months. You need to decide by Friday. But how do you evaluate architectural decisions without becoming a bottleneck or rubber-stamping bad ideas?

Most CTOs fall into one of two traps: either every decision runs through them (bottleneck), or they delegate completely and lose control (chaos). Neither scales.

You need a repeatable architecture review process that's rigorous without being bureaucratic, fast without being reckless, and democratic without being a free-for-all.

The Complete Architecture Review Framework

Part 1: When to Require an Architecture Review

Not every decision needs formal review. Use this criteria:

Triggers for Architecture Review

Always Require Review:

• New infrastructure (databases, message queues, caching layers)
• Major technology changes (language, framework, cloud provider)
• System-wide patterns (authentication, logging, error handling)
• Data architecture (schema changes affecting multiple services)
• Security or compliance implications
• Performance-critical systems (payment processing, real-time features)

No Review Needed:

• Implementation details within existing patterns
• Technology already approved on tech radar
• Prototypes or experiments (unless going to production)
• Refactoring within service boundaries
• Bug fixes

Decision Tree:

Does this decision affect multiple teams?
  YES -> Review required
  NO:
    Is this irreversible or costly to change?
      YES -> Review required
      NO:
        Does this introduce new technology to the stack?
          YES -> Review required
          NO -> No review needed (engineer autonomy)

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Part 2: The Architecture Review Board (ARB)

Who Should Be On It?

Core Members (Always present):

• CTO or VP Engineering (decision maker)
• Principal Engineer or Architect (technical depth)
• 2-3 Senior Engineers (rotating, represent different teams)

Optional Members (As needed):

• Security Engineer (for security-sensitive changes)
• DevOps Lead (for infrastructure changes)
• Product Manager (for product-impacting changes)
• DBA (for data architecture)

Size Rule: Keep it under 7 people total (Amazon's two-pizza rule)

Meeting Cadence

Weekly Sync (30-60 minutes):

• Review 1-3 proposals per week
• Recurring calendar invite
• Async pre-read required

Ad-Hoc Reviews (As needed):

• Critical path blockers
• Time-sensitive decisions
• Emergency architecture changes

Annual Calibration (Quarterly):

• Review tech radar
• Update review criteria
• Assess past decisions (what worked, what didn't)

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Part 3: The Architecture Proposal Template

Every proposal must follow this structure:

# Architecture Proposal: [Title]

**Author**: [Name]
**Date**: [YYYY-MM-DD]
**Status**: Draft | In Review | Approved | Rejected
**Review Date**: [When ARB will review]

## 1. Problem Statement

[What problem are we solving? Why now?]

**Current State**: [Describe existing system/approach]
**Pain Points**: [Specific issues we're facing]
**Impact**: [Who is affected? How much?]

## 2. Proposed Solution

[High-level description of the architecture]

**Key Changes**:
- Change 1
- Change 2
- Change 3

**Architecture Diagram**: [Include visual]

## 3. Alternatives Considered

### Option A: [Proposed Solution]
- **Pros**: [Benefits]
- **Cons**: [Trade-offs]
- **Cost**: [Estimated effort]

### Option B: [Alternative 1]
- **Pros**: [Benefits]
- **Cons**: [Trade-offs]
- **Cost**: [Estimated effort]

### Option C: [Do Nothing]
- **Pros**: [Benefits]
- **Cons**: [Trade-offs]
- **Cost**: [Estimated effort]

**Why we chose Option A**: [Rationale]

## 4. Technical Details

**Technology Stack**:
- [List technologies involved]

**Data Model Changes**:
- [Schema changes, migrations needed]

**API Changes**:
- [New endpoints, breaking changes]

**Security Considerations**:
- [Authentication, authorization, data privacy]

**Performance Impact**:
- [Latency, throughput, resource usage]

## 5. Implementation Plan

**Phase 1**: [Milestone 1] - [Timeline]
- [Task 1]
- [Task 2]

**Phase 2**: [Milestone 2] - [Timeline]
- [Task 3]
- [Task 4]

**Total Timeline**: [X weeks/months]
**Team Size**: [How many engineers]

## 6. Risks & Mitigation

| Risk | Likelihood | Impact | Mitigation |
|------|-----------|--------|------------|
| [Risk 1] | High/Med/Low | High/Med/Low | [How we'll address] |
| [Risk 2] | High/Med/Low | High/Med/Low | [How we'll address] |

## 7. Success Metrics

**How we'll measure success**:
- Metric 1: [Target]
- Metric 2: [Target]
- Metric 3: [Target]

**Rollback Plan**:
[How we'll revert if this fails]

## 8. Open Questions

1. [Question 1]
2. [Question 2]

## 9. Decision

**ARB Decision**: Approved | Rejected | Needs More Info
**Decision Date**: [YYYY-MM-DD]
**Conditions**: [Any requirements for approval]
**Next Steps**: [Action items]

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Part 4: The Review Criteria Scorecard

Use this scorecard to evaluate proposals objectively:

Scoring Matrix (1-5 scale)

1. Technical Soundness (Weight: 25%)

• Does the solution solve the stated problem?
• Is the architecture scalable and maintainable?
• Are best practices followed?
• Score: __/5

2. Feasibility (Weight: 20%)

• Do we have the skills to implement this?
• Is the timeline realistic?
• Are dependencies manageable?
• Score: __/5

3. Risk Management (Weight: 20%)

• Are risks identified and mitigated?
• Is there a rollback plan?
• What's the blast radius if it fails?
• Score: __/5

4. Alignment (Weight: 15%)

• Aligns with tech strategy/radar?
• Supports business goals?
• Fits team capacity?
• Score: __/5

5. Cost-Benefit (Weight: 10%)

• ROI is positive?
• Effort justified by impact?
• Total cost of ownership acceptable?
• Score: __/5

6. Security & Compliance (Weight: 10%)

• Security implications addressed?
• Compliance requirements met?
• Data privacy considered?
• Score: __/5

Total Score: [Calculate weighted average]

Approval Threshold:

• 4.0+: Approve
• 3.0-3.9: Approve with conditions
• under 3.0: Reject or request redesign

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Part 5: The Review Meeting Process

Before the Meeting (48 hours ahead)

Proposal Author:

1. Submit proposal using template
2. Post in #architecture Slack channel
3. Tag ARB members for async review

ARB Members:

1. Read proposal (15-30 min investment)
2. Score using criteria scorecard
3. Prepare 2-3 questions

During the Meeting (45-60 minutes)

Agenda:

1. Presentation (10 min) - Author walks through proposal
2. Clarifying Questions (10 min) - ARB asks questions
3. Discussion (15 min) - Debate trade-offs, alternatives
4. Scoring (5 min) - ARB members share scores
5. Decision (5 min) - Approve, reject, or conditions
6. Next Steps (5 min) - Action items, timeline

Meeting Roles:

• Moderator: CTO (keeps discussion on track)
• Scribe: Rotating senior engineer (documents decision)
• Timekeeper: Moderator or scribe

After the Meeting

Scribe:

• Updates proposal status (Approved/Rejected/Conditional)
• Documents decision rationale
• Posts summary in #architecture

Author:

• Implements approved changes
• Reports back on metrics after launch

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Part 6: Decision Frameworks

The RACI Matrix for Architecture

| Decision Type | Responsible | Accountable | Consulted | Informed | |--------------|------------|-------------|-----------|----------| | Propose architecture | Engineer | Engineer | ARB | Team | | Review proposal | ARB | CTO | Security, DevOps | Eng org | | Approve/Reject | CTO | CTO | ARB | Author | | Implement | Engineer | EM | ARB | Stakeholders | | Monitor success | Engineer | EM | CTO | ARB |

Delegation Levels

Level 1: Inform (Low risk, reversible)

• Engineer decides, informs ARB after
• Example: Choosing a logging library

Level 2: Consult (Medium risk)

• Engineer proposes, ARB advises, engineer decides
• Example: API design patterns

Level 3: Consensus (High risk, reversible)

• ARB discusses, seeks consensus, CTO tie-breaks
• Example: Database choice

Level 4: Approve (High risk, irreversible)

• ARB reviews, CTO approves/rejects
• Example: Cloud provider migration

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Part 7: Common Review Scenarios

Scenario 1: Microservices Migration

Red Flags to Watch For:

• Team under 20 engineers (too early)
• No clear service boundaries
• No DevOps/container expertise
• "Microservices will solve our problems" (cargo cult)

Questions to Ask:

• What specific problem does this solve?
• Have we tried a modular monolith first?
• Do we have the operational maturity?
• What's the migration path?

Approval Criteria:

• Clear service boundaries identified
• Team has container/orchestration skills
• Incremental migration plan (not big bang)
• Monitoring/observability plan

Scenario 2: New Database Technology

Red Flags:

• "NoSQL is better than SQL" (dogma)
• No one on team has production experience with it
• Version 1.0 or newer than 1 year old (immature)
• No clear read/write patterns defined

Questions to Ask:

• Why can't existing DB handle this?
• What's the data model and access patterns?
• Have we tested performance at scale?
• What's the operational overhead?

Approval Criteria:

• Clear use case (not just "new and shiny")
• Team has expertise or training plan
• Proven at similar scale in production
• Migration and rollback plan

Scenario 3: Third-Party Service Integration

Red Flags:

• Vendor lock-in without exit strategy
• Single point of failure
• No SLA or support tier
• Cost scales unpredictably

Questions to Ask:

• Build vs buy analysis done?
• What happens if vendor goes down/away?
• How does cost scale with usage?
• Data ownership and export options?

Approval Criteria:

• Abstraction layer to avoid lock-in
• Fallback/circuit breaker implemented
• Cost model understood and acceptable
• Contract reviewed by legal

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Part 8: Governance Models by Company Size

Startup (under 10 engineers)

ARB: CTO + 1-2 senior engineers Cadence: As needed (weekly if busy) Process: Lightweight (Slack proposal, 15-min review) Delegation: High (trust engineers, move fast)

When to formalize: When you hit 10+ engineers or have multiple teams

Growth (10-50 engineers)

ARB: CTO + Principal Engineer + 3 rotating seniors Cadence: Weekly 1-hour meeting Process: Formal template, scorecard, async pre-read Delegation: Medium (Level 1-2 decisions delegated)

This guide is designed for this stage

Scale (50+ engineers)

ARB: VP Eng + Architects + Domain leads Cadence: Weekly + domain-specific sub-committees Process: RFC (Request for Comments) + formal review Delegation: High (only Level 4 decisions require ARB)

Additional governance:

• Architecture guild (cross-team knowledge sharing)
• Tech radar (approved technologies)
• Reference architectures (templates for common patterns)

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Part 9: Architecture Decision Records (ADRs)

Supplement ARB process with ADRs for documentation:

ADR Template

# ADR-XXX: [Decision Title]

**Status**: Proposed | Accepted | Deprecated | Superseded
**Date**: YYYY-MM-DD
**Deciders**: [Who made the decision]

## Context

[What's the issue we're addressing? Background and constraints.]

## Decision

[What we've decided to do and why]

## Consequences

**Positive**:
- [Benefit 1]
- [Benefit 2]

**Negative**:
- [Trade-off 1]
- [Trade-off 2]

**Risks**:
- [Risk 1]: [Mitigation]
- [Risk 2]: [Mitigation]

## Alternatives Considered

### Option B
- [Why we didn't choose this]

### Option C
- [Why we didn't choose this]

## Related Decisions

- ADR-XXX: [Related decision]

Where to Store:

• Git repo: docs/adr/XXX-title.md
• Searchable by team
• Updated when decision changes

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Part 10: Avoiding Common Pitfalls

Mistake 1: Design by Committee

Problem: ARB becomes a debate club, no decisions made

Solution:

• CTO has final say (tie-breaker)
• 60-minute time limit
• If no consensus, default to "Approve with conditions" and iterate

Mistake 2: Rubber Stamping

Problem: ARB approves everything (no real review)

Solution:

• Track approval rate (should be 70-80%, not 100%)
• Require scorecard completion
• Celebrate rejections (shows process works)

Mistake 3: Analysis Paralysis

Problem: Reviews take weeks, engineers blocked

Solution:

• 1-week SLA for decision
• "Approve with monitoring" for uncertain cases
• Reversible decisions get fast-tracked

Mistake 4: Inconsistent Standards

Problem: Similar proposals get different outcomes

Solution:

• Reference past decisions (ADRs)
• Calibration sessions quarterly
• Publish decision criteria publicly

Mistake 5: No Follow-Up

Problem: Decisions approved but success never measured

Solution:

• 30/60/90 day check-ins
• Success metrics in proposal
• Annual "architecture retrospective"

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Tools and Templates

ARB Meeting Agenda Template

# Architecture Review Board - [Date]

**Attendees**: [List]
**Scribe**: [Name]

## Proposals for Review

### 1. [Proposal Title] - [Author]
- **Pre-read**: [Link to proposal]
- **Presenter**: [Name] (10 min)
- **Decision needed**: Yes/No
- **Time allocated**: 45 min

### 2. [Proposal Title] - [Author]
- [Same format]

## Follow-Ups from Previous Reviews

- [Decision 1]: 30-day check-in
- [Decision 2]: Rollback discussion

## Tech Radar Updates

- [Technology to add/remove]

## Open Discussion (10 min)

Slack Bot for ARB Workflow

Automate reminders and notifications:

/arb submit [link-to-proposal]
-> Posts to #architecture
-> Tags ARB members
-> Schedules for next meeting

/arb approve [proposal-id]
-> Updates status
-> Notifies author
-> Creates ADR stub

/arb metrics
-> Shows approval rate
-> Lists pending reviews
-> Highlights overdue follow-ups

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Success Metrics

How to know if your ARB is working:

Process Metrics

• Review SLA: 95% of proposals reviewed within 1 week
• Approval Rate: 70-80% (not too high, not too low)
• Meeting Efficiency: under 60 minutes per proposal
• Async Pre-Read Rate: 80%+ members score before meeting

Outcome Metrics

• Architecture Debt: Decreasing over time
• Incident Root Causes: under 20% architecture-related
• Engineer Satisfaction: 7+/10 on "ARB helps, doesn't block"
• Decision Reversals: under 10% (shows good initial decisions)

Long-Term Health

• Tech Stack Diversity: Controlled (not too many tools)
• Onboarding Time: New engineers productive faster
• Cross-Team Consistency: Similar problems solved similarly
• Innovation: Still able to experiment and adopt new tech

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Remember: The goal isn't to slow down decision-making—it's to make better decisions faster. A good ARB process gives engineers clarity, prevents costly mistakes, and scales decision-making beyond the CTO.