Migrate Api

Orchestrate comprehensive API version migrations with automated compatibility layers, breaking change detection, and zero-downtime deployment strategies. This command manages the complete lifecycle of API evolution from initial analysis through deployment and deprecation.

Design Decisions

Architecture Approach:

• Version routing at API gateway level for clean separation
• Adapter pattern for backward compatibility transformations
• Feature flags for gradual rollout control
• Automated test generation across all supported versions

Alternatives Considered:

• Hard cutover migration (rejected: high risk, no rollback)
• Separate API endpoints per version (rejected: operational complexity)
• GraphQL federation (chosen for microservices architectures)
• BFF pattern for client-specific migrations

When to Use

USE when:

• Introducing breaking changes to API contracts
• Deprecating legacy endpoints with controlled timelines
• Migrating between API paradigms (REST to GraphQL)
• Evolving data models with backward incompatible changes
• Implementing new authentication mechanisms
• Consolidating multiple API versions

DON'T USE when:

• Adding backward-compatible endpoints (use versioned routes)
• Making internal refactoring without contract changes
• Deploying hotfixes or security patches
• Changes affect only implementation, not interface

Prerequisites

Required:

• Complete OpenAPI/GraphQL schema for both versions
• Comprehensive API test suite with >80% coverage
• Version control with tagged releases
• Deployment pipeline with rollback capability
• API gateway with routing rules support
• Monitoring and alerting infrastructure

Recommended:

• Consumer registry with contact information
• Deprecation policy documented and communicated
• Traffic analysis showing endpoint usage patterns
• Backward compatibility test matrix
• Canary deployment environment

Migration Process

Step 1: Analysis and Impact Assessment

• Scan API schemas to detect breaking changes
• Analyze usage patterns from API logs
• Identify affected consumers and endpoints
• Calculate complexity score for migration effort
• Generate compatibility matrix between versions

Step 2: Compatibility Layer Generation

• Create adapter functions for data transformation
• Generate request/response mappers automatically
• Build version-specific validation schemas
• Implement fallback logic for missing fields
• Create deprecation warning middleware

Step 3: Migration Script Creation

• Generate database migration scripts for schema changes
• Create data backfill scripts for new required fields
• Build rollback procedures for each migration step
• Generate test fixtures for both API versions
• Create automated smoke tests for critical paths

Step 4: Routing and Deployment Configuration

• Configure API gateway version routing rules
• Set up feature flags for gradual rollout
• Implement traffic splitting for canary deployment
• Configure monitoring dashboards for version metrics
• Set up deprecation warning headers and logs

Step 5: Validation and Monitoring

• Execute automated test suite across all versions
• Verify backward compatibility with consumer tests
• Monitor error rates and performance metrics
• Track adoption rates for new version
• Schedule deprecation timeline communications

Output Format

migration_plan:
  api_name: "User Service API"
  source_version: "v1"
  target_version: "v2"
  breaking_changes:
    - endpoint: "/users"
      change_type: "field_removed"
      field: "username"
      severity: "high"
      affected_consumers: 15
    - endpoint: "/users/{id}"
      change_type: "response_structure"
      details: "Nested address object"
      severity: "medium"
      affected_consumers: 8

  compatibility_layer:
    adapters_generated: 12
…

Code Examples

Example 1: REST API v1 to v2 Migration with Breaking Changes

// API v1 → v2 Migration: User endpoint restructure
// BREAKING: Flattened user object to nested structure

// Source: /api/v1/users/{id}
{
  "id": 123,
  "name": "John Doe",
  "email": "[email protected]",
  "street": "123 Main St",
  "city": "San Francisco",
  "state": "CA",
  "zip": "94105"
}

// Target: /api/v2/users/{id}
{
  "id": 123,
  "name": "John Doe",
…

Example 2: GraphQL Schema Evolution

# Schema v1 (Deprecated)
type User {
  id: ID!
  username: String!  # DEPRECATED: Replaced by email
  email: String
  fullName: String
}

type Query {
  user(id: ID!): User
  users: [User!]!
}

# Schema v2 (Current)
type Address {
  street: String!
  city: String!
  state: String!
…