Software Development Lifecycle
by David Girón

Software Development Lifecycle: How we run it

In today’s fast-paced digital landscape, software development has become an integral part of many organizations.

With the increasing demand for efficient and reliable software systems, it’s essential to have a structured approach to ensure successful project delivery.

This is where the Software Development Lifecycle (SDLC) comes into play.

What is SDLC?

If you’re an experienced developer, it’s very likely you are already implementing some of these steps, even if you don’t realize it.

The Software Development Lifecycle is a series of phases that guide the development process from conception to deployment.

This process, cost-effective and time-efficient, is used to design and build high-quality software.

It provides a framework for planning, executing, and monitoring any information system (such as hardware, software applications, or even tasks) to ensure they meet customer and business requirements.

The SDLC helps teams manage complexity, reduce risks, and improve overall quality.

What’s the goal of using or implementing SDLC?

The primary objective of adopting SDLC is to ensure that software development projects are completed efficiently, effectively, and with minimal errors.

By following a structured approach, organizations can:

  • Reduce project timelines and costs
  • Improve software quality and reliability
  • Enhance collaboration and increase visibility among team members and stakeholders
  • Increase customer satisfaction through timely delivery and meeting their requirements

Common Phases

The SDLC typically consists of six to eight phases. While some variations may exist, the following are the most common phases:

Planning Phase

In this phase, the project scope, goals, and objectives are defined.

The team identifies stakeholders, outlines project timelines, and establishes a budget.

A thorough analysis of the problem domain and market requirements is also conducted.

Example: Imagine you’re building a new mobile app for a retail chain.

In the planning phase, you would define the project’s scope, identify stakeholders (e.g., customers, store managers), establish a timeline, and determine the budget, including the allocation of engineering members.

Design Phase

In this phase, the team creates a detailed design of the software system, including architecture, user interfaces, and system components.

The design should be based on the requirements gathered during the analysis phase.

Example: For your mobile app, you would create wireframes for each screen, define the UI/UX, and develop prototypes to test with users.

At this point along with the Planning Phase, it’s highly recommended to conduct several activities, such as SWOT Analysis, and Threat Modelling sessions. When established at an early stage, this heavily impacts in defining Security by Design for the project.

Implementation Phase

This is the core development phase where the software is built.

The team writes code, integrates components, and tests the system to ensure it meets requirements.

Example: Your development team would start building the mobile app using the design specifications created in the previous phase.

They would write code for each feature, integrate APIs, and test the app’s functionality.

Testing Phase

This phase involves verifying that the software meets the required standards and functions as intended.

The team conducts various types of tests, including unit testing, integration testing, and user acceptance testing (UAT).

By the way, we also have an article about how we implement Performance Load Testing with Locust that might be interesting to you!

Example: Your testing team would perform unit testing for each feature, integrate testing to ensure API connections work correctly,

and conduct UAT with real users to validate the app’s functionality.

Deployment Phase

In this phase, the software is deployed to production, where it can be accessed by end-users.

The team ensures that the deployment process is smooth, secure, and meets the required standards.

Example: For your mobile app, you would deploy it on the App Store or Google Play,

configure any necessary servers or infrastructure, and ensure the app is accessible to users.

Maintenance Phase

The maintenance phase involves monitoring the software in production, fixing issues, and making updates based on user feedback and changing business requirements.

Example: After deploying your mobile app, you would monitor usage patterns, fix bugs as they arise,

and make updates to improve the app’s performance or add new features based on customer feedback.

Disposal Phase

Although we want the project to succeed, at some point you may no longer provide support or maintenance for it.

The disposal phase involves retiring or decommissioning software that is no longer required or has been replaced by a newer version.

This phase ensures that old software does not become obsolete or pose security risks.

Example: If your mobile app is no longer meeting business requirements or is being replaced with a new version, you would retire the old app and ensure that all data is properly migrated to the new system, along with the removal of the involved resources, such as storage, databases, and so.

Additional Actions and Relating Phases

As we dive deeper into the Software Development Lifecycle, you may explore some additional actions and see how they relate to their matching phases.

  • Threat Modeling: Conduct threat modeling during the Design Phase to identify potential security threats and vulnerabilities in your software system. This will help you design a more secure architecture and implement effective countermeasures.
  • Supply Chain Security Awareness: During the Implementation Phase, ensure that your development team is aware of the importance of supply chain security and takes steps to validate the integrity of third-party components and libraries (eg. including version pinning, reproducible builds, provenance and attestation, Software Bill of Materials…).
  • Privacy by Design: Incorporate privacy-by-design principles during the Design Phase to ensure that your software system respects user privacy from the outset. This includes implementing data minimization, data anonymization, and other privacy-enhancing measures.
  • Data Encryption: Use data encryption techniques during the Implementation Phase to protect sensitive data at rest and in transit. This can include encrypting databases, files, and communication protocols.
  • Least Privilege: Implement least privilege access controls during the Deployment Phase to ensure that users only have access to the resources they need to perform their job functions. This reduces the attack surface and minimizes the impact of a potential breach.
  • Zero Trust Models: Adopt zero-trust models during the Implementation Phase by assuming that all users and devices are untrusted and validating their identity and permissions at every point of interaction.
  • Multi-Tenancy and Tenant Isolation: For those applicable projects, make sure to implement multi-tenancy and tenant isolation during the Design Phase to ensure that different customers or organizations can share a single software system without compromising each other’s data. This includes implementing logical segregation, role-based access control, and other isolation mechanisms.