Monolith to Microservices
Learn proven strategies for evolving monolithic applications into microservices architectures. Understand the trade-offs, decomposition patterns, and real-world lessons from successful migrations.
When to Consider Microservices
Microservices aren't always the answer. Consider migration when your monolith creates specific pain points that microservices can solve, and when you have the organizational maturity to handle the complexity.
Important: Start with a Monolith
Almost every successful microservices company started with a monolith. Premature microservices often fail because boundaries are unclear, requirements change rapidly, and teams lack experience with distributed systems.
Good Reasons to Migrate
Bad Reasons to Migrate
Migration Strategy: Incremental Evolution
Successful migrations happen gradually, not in a big-bang rewrite. Each stage reduces risk while moving toward your target architecture.
Modular Monolith
Low EffortLow RiskWell-structured monolith with clear module boundaries
- • Clear separation of concerns
- • Easier to understand
- • Single deployment
- • Still coupled deployment
- • Shared database
- • Technology lock-in
Database per Service
Medium EffortMedium RiskSplit database while keeping single codebase
- • Data ownership
- • Independent scaling
- • Technology flexibility
- • Data consistency
- • Cross-service queries
- • Migration complexity
API Gateway Pattern
High EffortMedium RiskExtract services behind unified gateway
- • Service discovery
- • Rate limiting
- • Authentication centralized
- • Single point of failure
- • Added latency
- • Gateway complexity
Full Microservices
Very High EffortHigh RiskIndependent services with own databases and deployment
- • Complete independence
- • Technology diversity
- • Team autonomy
- • Distributed system complexity
- • Network latency
- • Data consistency
Real-World Migration Stories
Learn from companies that successfully navigated the monolith-to-microservices journey. Each took a different approach based on their specific constraints and goals.
Netflix
Amazon
Uber
Monolith vs Microservices Trade-offs
Both architectures have their place. Understanding the trade-offs helps you make informed decisions about when and how to migrate.
Monolith Advantages
Microservices Advantages
Migration Decision Framework
Stick with Monolith If:
- ☐ Team size < 10 developers
- ☐ Domain boundaries are unclear
- ☐ Limited DevOps/infrastructure experience
- ☐ Tight coupling between business logic
- ☐ Performance is critical (low latency)
Consider Microservices If:
- ☐ Multiple teams, coordination issues
- ☐ Clear domain boundaries exist
- ☐ Different scaling requirements
- ☐ Technology diversity needed
- ☐ Strong DevOps culture and tooling
🎯 Microservices Migration Success Stories and Failures
Learn from real-world experiences: both successful migrations and costly mistakes
Scenarios
Context
How Spotify scaled to 100M+ users with autonomous teams and microservices
Metrics
Outcome
Successfully scaled both technology and organization. Squad model became industry standard for team autonomy.
Key Lessons
- •Microservices enable organizational scaling as much as technical scaling
- •Autonomous teams require strong engineering culture and tooling investment
- •Domain boundaries should align with team responsibilities
- •Conway's Law: system design mirrors communication structure