Migration Azure To AWS

1. AWS credits — Activate Accelerate / startup program credits are often larger than Azure equivalents
2. Team hires — new engineers know AWS, not Azure
3. Community and integrations — most SaaS integrations, tutorials, and community support default to AWS
4. Specific service — need Bedrock, DynamoDB, Lambda ecosystem, or other AWS-specific capabilities

Startup Migration Decision Framework

Don’t Migrate If:

• You have >$50K in remaining Azure credits with no AWS credits
• Your codebase has deep Azure SDK dependencies (>6 months to untangle)
• You’re pre-PMF — migration is a distraction from finding product-market fit
• Only reason is “AWS is more popular” — that’s not a technical reason

Do Migrate If:

• AWS credits significantly exceed remaining Azure credits
• Team is growing and candidates know AWS (hiring signal)
• Hitting Azure service limitations your product needs to overcome
• Want to consolidate on one cloud (already using some AWS)

Startup-Specific Migration Gotchas

Azure AD (Entra ID) — Skip the Full Migration

Enterprise migrations map Azure AD → IAM Identity Center. Startups should NOT:

• Migrate complex Conditional Access policies (rebuild from scratch with simpler IAM)
• Migrate Azure AD B2C to Cognito (re-auth your 50 users, it’s faster than migrating)
• Worry about PIM → IAM equivalent (you don’t need PIM at 5 engineers)

Startup approach: Set up IAM Identity Center fresh. Re-invite your 3-10 team members. Total time: 1 hour.

Cosmos DB — Don’t Over-Think It

Enterprise guide says “Cosmos DB maps to 4+ services depending on API.” For startups:

• If you use Cosmos DB Core (SQL API) → DynamoDB. Just port the queries.
• If you have <10GB of data → export JSON, import to DynamoDB. Done in a day.
• If you use MongoDB API → DocumentDB OR just DynamoDB (simpler, cheaper at startup scale)

Azure App Service → What to Choose on AWS

Azure Functions → Lambda

Straightforward except:

• Durable Functions → Step Functions (different programming model — budget 1-2 weeks to rewrite orchestrations)
• Bindings → Replace with explicit SDK calls. Budget 1-2 days per function with complex bindings.
• Timer triggers → EventBridge Scheduler + Lambda (easy, 30 min per function)

Startup Migration Execution Plan

The “Weekend Migration” (< 10 Azure resources, < 5GB data)

1. Friday: Set up AWS account, IAM Identity Center, basic networking
2. Saturday: Deploy compute (Lambda/ECS Express Mode/Fargate), migrate database (export/import)
3. Sunday: DNS cutover, smoke test, keep Azure running for 1 week as rollback
4. Following Friday: Delete Azure resources

The “Sprint Migration” (10-50 Azure resources, production traffic)

1. Week 1: Set up AWS foundation (accounts, networking, CI/CD)
2. Week 2: Deploy and validate in AWS (parallel running)
3. Week 3: Gradual traffic shift (Route 53 weighted routing)
4. Week 4: Decommission Azure (keep backups for 30 days)

Cost Comparison Traps