Authors: || Published: 2023-03-18T13:44:00 || Updated: 2025-11-28T14:39:00 || 4 min read
Categories: || Tags: || Post-format: standard
Software Engineering Architecture Decision Records (ADR)
Overview
Architecture Decision Record (ADR) is a point-in-time log entry of a design and/or architectural decision. This is usually the result of a pointed decision / discussion rather than a played-out design review process. ADR should also typically only address a specific problem / concern and it should be concise and lightweight as compared to a design document.
There is a certain inter-play between ADR, RFC (Request for Comments) and design documents. Sometimes ADRs are used as feeders for RFCs, but that is not necessary a hard and fast rule.
We will discuss RFC and design documents in separate posts. This post outlines a template for capturing a ADR.
Template
# Title
A short title summarizing the documented decision.
| Metadata | Value(s) |
| --------------------------- | ------------------------------------------------------------------------------------------------ |
| Status | Draft / Proposed / Under Review / Under Evaluation/ Accepted / Amended / Deprecated / Superseded |
| Date Created | YYYY-MM-DD |
| Date Last Updated | YYYY-MM-DD |
| Date Accepted/Rejected | YYYY-MM-DD (when final decision made) |
| Last Updated By | |
| Author(s) | |
| Engineering Team(s) | |
| Engineering Lead | |
| Primary Product Stakeholder | |
| Other Stakeholders | |
| Reviewer(s) | |
| Commenter(s) | |
| Superseded By | ADR-XXX (if applicable - use when decision is deprecated or superseded) |
## Problem Statement
What technical problem or architectural question needs resolution? What are the constraints, requirements, and success criteria that define this problem?
## Motivation and Context
Discussion of the technical and/or business requirements / use-cases that was the motivation for this decision. Include:
- Business drivers and user needs
- Technical constraints
- Timeline considerations
- Relationship to system goals (performance, scalability, security, etc.)
## Decision
Discussion of the decision with all relevant details. Be explicit about:
- What approach was chosen
- Key technical components and patterns
- Implementation approach
- Why this solution addresses the problem
## Consequences
Discussion of problem mitigation. Tradeoffs and risks (including short-term and/or long-term) should also be covered.
**Positive Consequences:**
- Benefits and advantages
- Problems solved
- Capabilities enabled
**Negative Consequences:**
- Limitations introduced
- Technical debt incurred
- Complexity added
- Migration effort required
**Neutral Consequences:**
- Changes in process or workflow
- New dependencies
- Operational impacts
## Alternatives
List of any alternatives that were considered with their pros and cons.
### Alternative 1: [Name]
**Description:** [Brief description]
**Pros:**
- [Benefit 1]
- [Benefit 2]
**Cons:**
- [Drawback 1]
- [Drawback 2]
**Why Not Chosen:** [Reason]
### Alternative 2: [Name]
[Repeat structure as needed]
## Success Criteria
How will we measure whether this decision was successful? Define specific, measurable outcomes:
- Performance metrics (e.g., achieves 1K QPS, 15s latency target)
- Adoption criteria (e.g., 3 services migrated by Q1 end)
- Operational metrics (e.g., Level 1 observability maturity achieved)
- Quality metrics (e.g., reduces bug count by X%, improves accuracy by Y%)
- Cost metrics (e.g., reduces GPU costs by Z%)
## Security & Compliance Implications
Impact on security posture and compliance requirements:
- **Security Impact:** [How this decision affects security - positive or negative]
- **Compliance Requirements:** [Federal, air-gapped, FedRAMP, etc.]
- **Zero Trust Alignment:** [How decision aligns with zero trust principles]
- **Audit Trail:** [What audit capabilities are enabled or required]
- **Data Protection:** [Encryption, isolation, access control implications]
## Technical Details
*Optional section for complex decisions requiring detailed technical documentation.*
- Architecture diagrams
- Sequence diagrams
- Code examples or pseudocode
- Configuration snippets
- API contracts
- Data models
- Performance benchmarks
- Database schemas
- Infrastructure requirements
## Implementation Plan
**Next Steps:**
- [ ] Task 1 - Owner: [Name] - Due: [Date]
- [ ] Task 2 - Owner: [Name] - Due: [Date]
- [ ] Task 3 - Owner: [Name] - Due: [Date]
**Dependencies:**
- Technical dependencies (other ADRs, infrastructure, etc.)
- Team dependencies (which teams need to coordinate)
- External dependencies (vendor, tools, etc.)
**Timeline:**
- Q1 2026: [Milestones]
- Q2 2026: [Milestones]
**Responsible Parties:**
- DRI (Directly Responsible Individual): [Name]
- Implementation Team: [Team name(s)]
- Review & Approval: [Names]
## References
**Related ADRs:**
- ADR-XXX: [Title and relevance]
- ADR-YYY: [Title and relevance]
**Design Principles:**
- [Principle 1]: [How this decision aligns]
- [Principle 2]: [How this decision aligns]
**Supporting Documents:**
- Architecture Design Document: [Link/reference]
- Performance Requirements: [Link/reference]
- Benchmarks: [Link/reference]
- Research: [Link/reference]
**Discussion References:**
- Architecture Breakout Day X: Lines [X-Y]
- Working Document: Lines [X-Y]
- Slack thread: [Link]
- Meeting notes: [Date and link]
**External Resources:**
- Industry standards or best practices referenced
- Third-party documentation
- Academic papers or research
---
## Revision History
| Date | Version | Changes | Author |
| ---------- | ------- | --------------------- | ------ |
| YYYY-MM-DD | 0.1 | Initial draft created | [Name] |
| YYYY-MM-DD | 1.0 | Accepted | [Name] |
When to use which:
| Aspect | Technical Design Document (TDD) | Architecture Decision Record (ADR) |
|---|---|---|
| Scope | Feature/system/component | Specific architectural decision |
| Detail | Comprehensive implementation | Focused decision rationale |
| Audience | Entire team + stakeholders | Architects + leads |
| Lifecycle | Living document (updated) | Point-in-time decision record |
| Example | “Ingestion Pipeline Design” | “ADR-001: Event-Driven for Ingestion” |
TDD should reference relevant ADRs, and vice versa.