Stage 3 & 4: Design & Development

After defining what to build, the focus shifts to how to build it and the actual implementation.

Stage 3: Designing Architecture

Architects and senior developers create a design specification based on the requirements. This stage involves defining the software's internal structure and data flow.

Design Levels

• High-Level Design (HLD): Overall system architecture, database design, and module interaction.
• Low-Level Design (LLD): Detailed logic for individual modules, classes, and APIs.

[!NOTE] A good design minimizes the risk of architectural flaws that could be fatal to the project in later stages.

Stage 4: Building & Coding

This is the stage where developers actually write the source code. It is often the longest phase of the SDLC.

• Development: Implementing features based on the design spec.
• Coding Standards: Following consistent naming and structural rules.
• Peer Review: Ensuring code quality through collaborative reviews.
• Documentation: Adding comments and READMEs for future maintenance.

[!IMPORTANT] DevOps Focus In a DevOps culture, developers prioritize small, frequent code commits and automated unit testing to ensure the "Build" stage is always stable.