ADRs document important architectural decisions. After using ADRs in production, here’s how to create and maintain them effectively.

What are ADRs?

ADRs:

  • Document decisions - Why, not just what
  • Context - Situation and constraints
  • Consequences - Trade-offs and impacts
  • History - Decision timeline

ADR Format

Template

# ADR-001: Use PostgreSQL for Primary Database

## Status
Accepted

## Context
We need to choose a primary database for our application.
Requirements:
- ACID transactions
- Complex queries
- Relational data
- Strong consistency

## Decision
We will use PostgreSQL as our primary database.

## Consequences

### Positive
- ACID compliance
- Rich feature set
- Strong community
- Proven reliability

### Negative
- Requires expertise
- Vertical scaling limits
- More complex than NoSQL

## Alternatives Considered
- MySQL: Less features
- MongoDB: No ACID transactions
- DynamoDB: Vendor lock-in

When to Create ADRs

Create ADRs For:

  • Technology choices - Databases, frameworks
  • Architecture patterns - Microservices, monolith
  • Design decisions - API design, data models
  • Process changes - Deployment, testing

Don’t Create ADRs For:

  • Implementation details - Code-level decisions
  • Temporary decisions - Short-term fixes
  • Obvious choices - No alternatives

ADR Examples

Technology Choice

# ADR-002: Use React for Frontend

## Status
Accepted

## Context
We need to choose a frontend framework for our web application.

## Decision
Use React with TypeScript.

## Consequences
- Large ecosystem
- Strong typing
- Component reusability
- Learning curve

Architecture Pattern

# ADR-003: Microservices Architecture

## Status
Accepted

## Context
Application is growing, monolith becoming hard to maintain.

## Decision
Migrate to microservices architecture.

## Consequences
- Independent scaling
- Technology diversity
- Increased complexity
- Network overhead

ADR Management

File Structure

docs/
  adr/
    0001-use-postgresql.md
    0002-use-react.md
    0003-microservices.md

Status Values

  • Proposed - Under consideration
  • Accepted - Decision made
  • Deprecated - Replaced
  • Superseded - By another ADR

Best Practices

  1. Number ADRs - Sequential numbering
  2. Keep focused - One decision per ADR
  3. Update status - Track changes
  4. Link related - Reference other ADRs
  5. Review regularly - Keep current
  6. Make accessible - Easy to find
  7. Include context - Why, not just what
  8. Document consequences - Trade-offs

Conclusion

ADRs provide:

  • Decision history
  • Context preservation
  • Team alignment
  • Knowledge sharing

Start documenting important decisions. The format shown here captures decision context effectively.

Architectural Decision Records from December 2021, covering ADR format and best practices.