7 Core software development phases in the Software Development Life Cycle (SDLC)

The SDLC is typically broken down into seven distinct phases. While some methodologies might blend or repeat these steps, they form the core of nearly every project.

1. Requirement Gathering & Analysis

• Purpose: This is the foundational stage. Its goal is to understand and document what the software must do. This involves identifying all stakeholders—users, clients, investors—and defining the project's objectives. What problem are we solving? Who is it for?
• Methods: Techniques include stakeholder interviews, user surveys, competitor analysis, and creating a Business Requirement Document (BRD). Clear documentation of software project requirements is paramount.
• Tools: Jira, Confluence, Trello, Google Forms, Miro.
• Best Practice: Don't just ask what they want; ask why they want it. Understanding the underlying business need leads to better solutions. This is the suggested first step for entering software development on any project.
• Example: A retail company wants an e-commerce app. The analysis phase would involve interviewing the marketing team (for branding), the warehouse manager (for inventory integration), and potential customers (for desired features like wishlists and easy checkout).

2. software development planning

• Purpose: Once requirements are clear, this stage focuses on building a project roadmap. This involves estimating cost, time, and technical resources needed. A key output is the Software Requirements Specification (SRS) document, which details all technical and functional specifications. It's also where you conduct a software project planning and risk assessment.
• Methods: Creating a detailed project plan, resource allocation, and a feasibility study (technical, economic, operational). Accurate software development estimation is critical here to manage expectations and software development costs.
• Tools: Microsoft Project, Smartsheet, GanttPRO.
• Best Practice: Involve senior developers and architects in the feasibility study to ensure technical viability. Always plan for contingencies.
• Example: The retail app project team determines they need two frontend developers, one backend developer, a QA engineer, and a project manager for six months. They estimate a budget of $150,000 and identify a risk that their current inventory system may be difficult to integrate with, creating a mitigation plan to address it.

3. UI/UX Design

• Purpose: This stage is about designing the software's look, feel, and user experience. It’s not just about aesthetics; it’s about creating an intuitive, efficient, and enjoyable journey for the user.
• Methods: Creating wireframes (basic layout), mockups (visual design), and interactive prototypes. User journey mapping helps visualize how a user will interact with the product. The software UI design process and UX wireframes are key deliverables.
• Tools: Figma, Adobe XD, Sketch, InVision.
• Best Practice: Prioritize accessibility (WCAG standards) and responsive design to ensure the software works for everyone on any device. Conduct user testing on prototypes before writing a single line of code.
• Example: Designers for the retail app create a low-fidelity wireframe to map out the user flow from login to purchase. After approval, they build a high-fidelity, clickable prototype in Figma that looks and feels like the final app, which is then tested with a small group of users for feedback.

4. Software Development / Coding

• Purpose: This is where the magic happens. The development team takes the design documents and SRS and starts building the actual software. This coding phase of SDLC involves both frontend (what the user sees) and backend (server, database, logic) implementation.
• Methods: Writing code in the chosen programming languages (e.g., Python, JavaScript, Java), using frameworks (e.g., React, Django, Spring), and managing code with version control systems. Adherence to coding standards is crucial.
• Tools: VS Code, IntelliJ IDEA, GitHub, GitLab, Docker.
• Best Practice: Use a version control system like Git from day one. Implement Continuous Integration/Continuous Deployment (CI/CD) practices to automate builds and tests, catching issues early.
• Example: The frontend developer uses React Native to build the app's user interface, while the backend developer uses Python with the Django framework to build the API that handles user data, products, and orders. Their code is stored and managed on GitHub.

5. Testing & Quality Assurance

• Purpose: To find and fix bugs before they reach the user. This phase ensures the software meets the specified requirements and is free of defects. QA testing in software development is non-negotiable for a quality product.
• Methods: A variety of testing types are used:
  
  • Unit Testing: Testing individual components.
  • Integration Testing: Testing how components work together.
  • System Testing: Testing the complete, integrated system.
  • User Acceptance Testing (UAT): Real users validate that the software meets their needs.
• Tools: Selenium, Cypress (for automated software testing), Postman (for API testing), Jira (for bug tracking).
• Best Practice: In Agile, testing is not a separate phase but a continuous activity. The role of a Software Development Engineer in Test is crucial here, focusing on creating automated tests that run with every new code commit.
• Example: The QA team tests the retail app's checkout process. They use Selenium to automate a script that adds an item to the cart, enters shipping details, and confirms the order, ensuring it works flawlessly every time. They manually test edge cases, like what happens if the internet connection drops mid-purchase.

6. Deployment & Go-Live

• Purpose: To make the software available to users. The software deployment process involves moving the code from a development environment to a live production environment.
• Methods: Deploying to cloud platforms (AWS, Azure, Google Cloud) or on-premise servers. A staging environment, which is a replica of production, is used for final testing before the official launch.
• Tools: Jenkins, Docker, Kubernetes, AWS Deploy, Netlify.
• Best Practice: Have a rollback plan. If the deployment fails or causes critical issues, you need a quick way to revert to the previous stable version. Implement monitoring and logging to track performance and errors post-launch.
• Example: After successful UAT, the retail app is deployed to a staging server for a final check. Once cleared, it's pushed to the production servers and published on the Apple App Store and Google Play Store. The team monitors server logs and performance dashboards closely for the first 48 hours.

7. Maintenance & Continuous Improvement

• Purpose: The journey isn't over at launch. Post-launch software maintenance ensures the software remains secure, stable, and relevant over time. This involves fixing bugs, applying security patches, and making performance upgrades.
• Methods: Establishing feedback loops (support tickets, reviews) to collect user input for future updates. Using DevOps or Agile principles allows for continuous software delivery of small, incremental improvements rather than waiting for a big "version 2.0."
• Tools: Zendesk (for support tickets), Sentry (for error tracking), Datadog (for monitoring).
• Best Practice: Schedule regular maintenance windows. Treat user feedback as a valuable resource for planning your future product roadmap.
• Example: A month after launch, users report that the app's search function is slow. The development team analyzes the issue, optimizes the database query, and deploys a patch to improve performance—all without requiring a major new release.