The Architecture Dilemma

When starting a SaaS, the "Monolith First" approach is often recommended. But as your team and feature set grow, the friction of a single codebase can become a bottleneck.

When to Stay Monolithic

• Early Stage: Speed of development is paramount.
• Small Teams: Avoiding the overhead of network calls and service orchestration.
• Simplified Deployment: One build, one deploy.

Transitioning to Microservices

• Team Isolation: Allowing different teams to work on independent services.
• Polyglot Stacks: Using the best language for each specific job.
• Independent Scaling: Scaling only the parts of the app that face high traffic (e.g., the billing engine vs. the settings page).

The Hybrid Approach

Many successful SaaS companies use a "Modular Monolith," where the code is structured as independent modules within a single repository, easing a future transition to microservices if necessary.