Monolithic Vs Microservices Architectures | Overview.

Monolithic Vs Microservices Architectures - Overview.

Scope:

• Intro,
• Definition,
• Architecture,
• Development & Deployment,
• Scalability,
• Resilience,
• Technology Stack,
• Data Management,
• Benefits & Limitations,
• Use Cases,
• Final takeaway.

Intro:

• Monolithic and microservices architectures are two distinct approaches to building software applications, with the former (Monolthic) structuring all components into a single, unified codebase and the latter (Microservices) breaking the application into small, independent services

1. Definition

• Monolithic Application
• A single, unified codebase where all features (UI, business logic, and data access) are tightly coupled and deployed as one unit.
• Microservices Application
  An application composed of small, independent services, each focused on a specific business capability, communicating via APIs or events.
• An application composed of small, independent services, each focused on a specific business capability, communicating via APIs or events.

2. Architecture

• Monolith
• One codebase, one build, one deployment.
• Shared database across modules.
• Scaling = scale the entire application.
• Microservices
• Multiple independent services (each has own repo, CI/CD pipeline).
• Each service owns its own database (decentralized data).
• Scaling = scale only the bottleneck service.

3. Development & Deployment

• Monolith
• Easy to start, fewer moving parts.
• Any change → redeploy entire app.
• Harder to scale with multiple dev teams (tight coupling).
• Microservices
• Independent deployability.
• Teams own different services (domain-driven ownership).
• Faster iteration, but requires strong DevOps maturity.

4. Scalability

• Monolith
• Limited: must scale whole app even if only one feature needs more resources.
• Microservices
• Fine-grained: scale specific services independently (e.g., scale only “Payments” under heavy load).

5. Resilience

• Monolith
• Single point of failure (crash in one part can bring down the whole system).
• Microservices
• Failure isolation: one service down doesn’t necessarily break others (if designed well).
• Requires resilience patterns (circuit breakers, retries).

6. Technology Stack

• Monolith
• Usually one tech stack for the whole app.
• Example: Java Spring Boot + MySQL.
• Microservices
• Polyglot freedom: each service can use its best-suited stack.
• Example:
• Orders → Java + MySQL
• Payments → Go + Cassandra
• Notifications → Node.js + Kafka

7. Data Management

• Monolith
• Single, shared database schema.
• Easier to query across features.
• Microservices
• Decentralized, per-service databases.
• Harder cross-service queries (need APIs/events instead of joins).
• Eventual consistency (vs monolith’s strong consistency).

8. Observability & Operations

• Monolith
• Easier to monitor/log (single process).
• Debugging simpler but app can be huge.
• Microservices
• Requires centralized logging, metrics, tracing.
• Distributed debugging is harder.
• Needs service discovery, load balancing, monitoring tools.

9. Benefits & Limitations

Aspect	Monolithic	Microservices
Speed to Start	✅ Easy to build, test, and deploy	❌ Complex to set up infra, CI/CD
Performance	✅ Less network overhead	❌ Network latency between services
Scaling	❌ Whole app must scale	✅ Independent scaling
Resilience	❌ One bug can crash whole system	✅ Failure isolation
Data	✅ Simple joins, strong consistency	❌ Distributed data, eventual consistency
Flexibility	❌ One stack for all	✅ Polyglot freedom
Team Size Fit	✅ Small teams/startups	✅ Large orgs with domain-driven teams

10. Use Cases

• Monolith is better when:
• Startup/MVP (need to ship fast).
• Small team.
• Simple system with limited scalability needs.
• When consistency is critical and cross-domain queries are frequent.
• Microservices are better when:
• Large, complex applications with many business domains.
• Organization has multiple independent teams.
• Needs high scalability, resilience, and continuous delivery.
• Examples: E-commerce platforms, fintech, streaming services.

Final takeaway:

• Monolith = great for simplified, small teams, MVPs ( minmum viable products).
• Microservices = great for scalability, resilience, large orgs — but require DevOps maturity and operational investment.