Architecture Decision Records (ADRs) document important architectural decisions made during the development of a system. This guide provides standards for creating, storing, and managing ADRs across Bayat projects to ensure consistent decision documentation and knowledge preservation.
ADRs serve several important purposes:
- Knowledge Preservation: Capture the context, reasoning, and alternatives considered
- Onboarding: Help new team members understand why systems are built the way they are
- Future Decision Making: Provide context for related decisions in the future
- Communication: Create clear documentation of decisions for stakeholders
- Consistency: Promote thoughtful and consistent architectural evolution
Create an ADR when making decisions that:
- Have a significant impact on the architecture
- Affect multiple teams or components
- Establish patterns or standards
- Involve technical risk or uncertainty
- Represent significant trade-offs
- Change previous architectural decisions
- Have long-term implications
- Selection of frameworks or technologies
- Significant design patterns adoption
- System integration strategies
- Security architecture decisions
- Data storage and management approaches
- API design principles
- Performance and scalability strategies
- Cross-cutting concerns implementation
- Major refactoring or migration plans
Each ADR should include the following sections:
- Title: Clear, concise title describing the decision
- Status: Current status of the decision
- Context: Background and factors that influenced the decision
- Decision: The decision that was made
- Consequences: Resulting outcomes, both positive and negative
- Compliance: How adherence to the decision will be verified (optional)
- Notes: Additional information, links to related ADRs (optional)
- Proposed: Decision under consideration
- Accepted: Decision approved and active
- Superseded: Decision replaced by a newer decision (reference the new ADR)
- Deprecated: Decision no longer relevant but not replaced
- Rejected: Decision considered but not adopted
Include the following metadata at the top of each ADR:
- ADR ID (sequential number)
- Author(s)
- Date Created
- Date Last Modified
- Related ADRs (if applicable)
- Stakeholders
# ADR-NNN: Title of the Architecture Decision
## Metadata
- **Status:** [Proposed | Accepted | Superseded | Deprecated | Rejected]
- **Author:** [Author Name(s)]
- **Date Created:** YYYY-MM-DD
- **Date Last Modified:** YYYY-MM-DD
- **Related ADRs:** [List related ADR references]
- **Stakeholders:** [List key stakeholders]
## Context
[Describe the forces at play, including technological, business, and project constraints. These forces may be in tension, and the decision attempts to resolve that tension. Describe alternatives considered and any prior decisions or principles that affected this decision.]
## Decision
[State the decision clearly and concisely. Use active voice: "We will..."]
## Consequences
### Positive
[List the positive consequences of the decision]
### Negative
[List the negative consequences or risks of the decision]
### Neutral
[List any neutral outcomes or trade-offs]
## Compliance
[Optional: Describe how this decision will be implemented and how adherence will be measured or verified]
## Notes
[Any additional information, links, or references that might be useful]- Identify need: Determine that a decision requires an ADR
- Draft: Author creates draft ADR with "Proposed" status
- Review: Share with stakeholders for feedback
- Revise: Update based on feedback
- Decide: Finalize the decision
- Publish: Update status and publish to repository
- Communicate: Notify relevant teams about the new ADR
When reviewing an ADR, consider:
- Are all significant alternatives documented?
- Is the context sufficiently explained?
- Are the consequences fully explored?
- Is the decision clearly stated?
- Are all stakeholders consulted?
- Is the decision consistent with existing ADRs?
When a decision changes:
- Create a new ADR documenting the new decision
- Reference the previous ADR being superseded
- Update the status of the old ADR to "Superseded"
- Add a reference in the old ADR to the new one
- Clearly explain why the previous decision is being changed
Store ADRs in a dedicated directory within your project repository:
/docs/architecture/decisions/
├── README.md # Overview of ADRs
├── template.md # ADR template
├── 0001-record-architecture-decisions.md
├── 0002-use-postgresql-for-primary-data-store.md
├── 0003-adopt-react-for-frontend.md
└── ...
Name files according to the pattern:
NNNN-short-title-with-hyphens.md
Where NNNN is a four-digit sequential number that does not repeat.
Maintain an index of all ADRs in a README.md file with:
- ADR number
- Title
- Status
- Date
- Brief description
For architectural decisions that apply across multiple projects:
- Store in a central architecture repository
- Reference from project-specific repositories
- Clearly indicate scope of applicability
- Include representatives from affected teams in review
When a project needs to deviate from an organization-wide ADR:
- Create a project-specific ADR
- Reference the organization-wide ADR
- Clearly explain the rationale for the exception
- Get approval from architecture governance
- Markdown Editors: VSCode, Typora, etc.
- ADR Management Tools:
- adr-tools (CLI tool)
- adr-log (generating logs/summaries)
- docToolchain (visualization)
- Include ADR reviews in architecture review meetings
- Reference ADRs in design documents and technical specifications
- Link ADRs to related issues in project management tools
- Include ADR creation in Definition of Done for significant features
Consider creating visualizations to show:
- Relationships between ADRs
- Timeline of architectural evolution
- Decision trees for complex decisions
- Heat maps showing affected components
- Use clear, concise language
- Focus on the "why" not just the "what"
- Avoid technical jargon where possible
- Be specific about requirements and constraints
- Use diagrams to illustrate complex concepts
- Keep it brief (aim for 1-2 pages per ADR)
- Too vague: Lacking specific details on implementation
- Too detailed: Including unnecessary implementation details
- Missing context: Not explaining the factors that led to the decision
- Incomplete alternatives: Not fully exploring other options
- Overlooking consequences: Not considering all impacts
- Isolated decisions: Not relating to other architectural decisions
- Regularly review ADR process and templates
- Solicit feedback on ADR usefulness
- Update older ADRs with new insights when appropriate
- Archive outdated ADRs rather than deleting them
- ADR writing workshops
- Examples of well-written ADRs
- Review sessions for feedback
- Templates and guides for different types of decisions
- Start with most critical decisions
- Include ADRs in architectural reviews
- Recognize and celebrate good ADRs
- Share success stories of how ADRs helped projects
- ADR GitHub Organization
- Thoughtworks Technology Radar - Lightweight Architecture Decision Records
- Documenting Architecture Decisions by Michael Nygard
- Sustainable Architectural Design Decisions
# ADR-0005: Adopt React for Frontend Applications
## Metadata
- **Status:** Accepted
- **Author:** Jane Smith
- **Date Created:** 2023-05-15
- **Date Last Modified:** 2023-06-02
- **Related ADRs:** ADR-0003 (API Design Principles)
- **Stakeholders:** Frontend Team, UX Team, Product Management
## Context
Our organization needs a standard frontend framework for web applications. Currently, teams use various frameworks (Angular, Vue, React) based on team preference, which has led to:
- Difficulty sharing components between projects
- Challenges in developer mobility between teams
- Inconsistent user experiences
- Duplicate training and tooling
We evaluated Angular, React, and Vue.js against the following criteria:
- Developer availability and learning curve
- Performance and bundle size
- Component reusability
- Enterprise support and longevity
- Testing capabilities
- Mobile support
## Decision
We will adopt React as our standard frontend framework for new web applications and gradually migrate existing applications during their next major version upgrade.
## Consequences
### Positive
- Unified component library can be developed and shared
- Easier to move developers between projects
- Consolidated training and documentation
- Consistent patterns for state management and API integration
### Negative
- Teams currently using Angular or Vue will need retraining
- Migration effort for existing applications
- Some teams may resist standardization
### Neutral
- Need to establish React-specific coding standards
- Will require updates to CI/CD pipelines for optimal React builds
## Compliance
- All new frontend applications must use React unless an exception is granted
- Existing applications should include migration plans in their roadmap
- Frontend architecture team will review compliance during quarterly assessments
## Notes
React was chosen over Angular primarily due to its smaller learning curve and over Vue due to its larger ecosystem and enterprise adoption.# ADR-0008: Use PostgreSQL for Transactional Databases
## Metadata
- **Status:** Accepted
- **Author:** John Doe
- **Date Created:** 2023-07-10
- **Date Last Modified:** 2023-07-22
- **Related ADRs:** ADR-0012 (Data Access Patterns)
- **Stakeholders:** Database Team, Operations, Security
## Context
We need to standardize our relational database technology choice for transactional systems. Currently, we use a mix of MySQL, SQL Server, and Oracle databases, which has resulted in:
- Increased operational complexity
- Varied backup and disaster recovery procedures
- Different security models
- Licensing cost variations
- Inconsistent developer experience
We evaluated PostgreSQL, MySQL, SQL Server, and Oracle against:
- Performance characteristics
- Feature completeness
- Operational requirements
- Licensing costs
- Cloud provider support
- Security capabilities
- Developer productivity
## Decision
We will use PostgreSQL as our standard relational database for all new transactional applications and plan migrations for existing applications where feasible.
## Consequences
### Positive
- Eliminated database license costs
- Consistent operational procedures
- Rich feature set including advanced data types and indexing
- Strong cloud provider support
- Excellent reliability and data integrity
### Negative
- Migration effort for existing applications
- Need for PostgreSQL-specific expertise
- Some proprietary features from other databases not available
### Neutral
- Will need to establish PostgreSQL-specific optimization guidelines
- Backup and HA solutions will need standardization
## Compliance
- All new applications requiring a relational database must use PostgreSQL
- Exceptions require architecture review board approval
- Quarterly database inventory will track migration progress
## Notes
PostgreSQL's combination of enterprise features, cost model, and cloud support makes it the optimal choice despite the migration challenges.
| Version | Date | Description |
|---|---|---|
| 1.0 | 2025-03-20 | Initial version |