SDLC Vs Agile: Which one is the best?

Quixy Editorial Team

August 29, 2023

Since the advent of software, the world has become much more sophisticated in the last two decades. In the world of information technology, businesses and individuals are continually innovating and developing software and programs.

Any software solution’s success depends on its methodology and the quality of effort put into its development.

The software development process used to be ambiguous and inefficient, resulting in inconsistent and unpredictable results before software development models were introduced. Standards to reduce mismatches between product expectations and prototypes were achieved by using standard frameworks and models. SDLC Vs Agile has been the standard question; let’s dive deep into understanding these.

What is SDLC?

The Software Development Life Cycle is referred to as SDLC. The SDLC helps us deliver software with the highest quality at the lowest cost.

Using SDLC, an organization can develop software in a well-structured way and maintain quality by testing and validating user specifications before releasing the software to a live environment. SDLC offers a well-structured flow of different phases.

An application development life cycle is also known as the Software Development Life Cycle or SDLC, and it can be used to develop both hardware and software components.

Iterative and incremental processes are incorporated into the SDLC model. Ensuring quick delivery of a working software solution, it focuses more on customer satisfaction and process adaptability.

Phases of SDLC

SDLC consists of various phases.

1. Planning

The first step is to gather and analyze requirements. This process includes getting customer input, meeting senior managers, and learning about sales and marketing. The requirements should be properly documented. The document is referred to as the Software Requirements Specification (SRS). As part of the project life cycle, the product requirements are outlined.

2. Design 

Using the output of the initial phase, the SRS document (Software Requirement Specification), we generate a software architecture for implementing system development. 

In addition to identifying and specifying the system and hardware requirements, this phase also helps define the overall programming language framework, database architecture, and system architecture.

The system design specifications are used as input in the next phase of the model.

3. Implementation

A suitable programming language is used in the implementation of the project. Compilers, interpreters, code editors, integrated development environments, and debuggers can all be used to write and test programs. Depending on the application, the programming language can be chosen. During this phase, the developed module is tested unit by unit.

4. Testing 

Testing ensures that a software program works as expected. This way, we can determine whether the final project meets the requirements. Testing includes integration testing, system testing, etc. Two modules are tested together during integration testing, and a system test is a complete project test.

5. Delivery/Deployment

Ultimately, the product is released in the market. A brand-new feature can be added to the product based on customer feedback. Existing customers receive maintenance and the required services. SDLC consists of these major phases.

6. Maintenance

Publishing the software does not end the process. You need to be checking, tracking and analyzing it on timely basis to ensure that you are extracting actual value out of it. The operation needs a lot of operational maintenance after launch.

Also Read: 4 SDLC Pain Points of Traditional Development and solving them with No-Code

What is Agile Methodology?

The Agile model believes every project needs to be handled differently and existing methods must be tailored to suit the requirements properly. A release is divided into time boxes to deliver specific features.

An iterative approach is taken, and the working code is delivered after each iteration. Each build is incremental in terms of features; the final build holds all the features required by the customer.

As a result of its flexibility and adaptability, the Agile thought process became popular with time in software development.

Rational Unified Process (1994), Scrum (1995), Crystal Clear, Extreme Programming (1996), Adaptive Software Development, feature-driven development, and Dynamic Systems Development Method (DSDM) (1995) are some of the most popular Agile methodologies.

The Agile Manifesto has the following principles:

• Co-location and pair programming are key interactions in Agile development. Self-organization and motivation are also significant.
• Instead of just relying on documentation, demoing working software is considered one of the most effective ways to communicate with customers.
• Getting proper product requirements requires continuous customer interaction, as the requirements cannot be fully gathered at the beginning of the project due to various factors.
• Agile development emphasizes quick responses to change and continuous improvement.

Basic Difference Between SDLC vs Agile

• In the Information Technology or Hardware Industries, SDLC (Software Development Life Cycle) refers to developing a product or service to deliver to the customer. It is used to design and develop software or systems for customer delivery. Agile is a method of project management that can be implemented using the Scrum framework for project management.
• An SDLC involves LLDs (Low-Level Designs) and HLDs (High-Level Designs), which are used differently, depending on the department’s technical or business expertise, to analyze and understand the project. The phases of Agile include Planning, Requirements, Analysis, Design, Coding, Unit Testing, System Integration Testing, Non-Functional Testing, and Acceptance Testing.
• In comparison, SDLC is easier to know and understand at a glance, while Agile is simpler to use and implement. As SDLC has different models, the parts of the project are managed differently, while Agile is more flexible and easier to manage.
• The SDLC process consists of several models, such as Waterfall, Agile, Iterative or incremental, Spiral, Rapid Application Development, V-Shaped, and Evolutionary prototype models, while Agile contains a set of best engineering practices and best standards as well as saves money, increases predictability, reduces failures, and improves the quality of the product.
• There are 12 principles in the Agile manifesto, whereas the SDLC describes all the activities that must be carried out for successful project delivery, maintenance, and support.
• Every step of the SDLC is documented in detail at each stage so that progress can be seen efficiently. In contrast, Agile provides continuous integration and delivery by delivering small changes in applications with frequent deliverables according to dynamic requirements changes.
• Using SDLC, the software is developed systematically, ensuring successful product deliverables within deadlines, while Agile develops software quickly and efficiently.

Core Difference between SDLC vs Agile methodologies

Benefits of SDLC

• One of the easiest, most common, and most manageable models is this one.
• Each phase of the project has its deliverables and review process due to its nature.
• It is well suited for small-to-medium-sized projects with clearly defined and understandable requirements.
• Implementation and planning are done in two directions (forward and backwards).
• Documentation of the process and results is thorough.
• Processes, tasks, and results are well documented in SDLC.
• The Software Requirement Specification document provides enough detail for the Software testers to design and simulate test cases and scenarios during the Software testing phase. As a result, the SDLC methodology makes the testing process much easier and more transparent.

Limitations of the SDLC Model

The following are the main points of the SDLC model–

• This is not the ideal model for a large, complex, and ongoing project.
• It is less effective if the requirement is unclear at the beginning.
• Making changes in the previous phases is very difficult.
• Once development is complete, testing begins. Therefore, it is likely to discover bugs later in development, which will be costly to fix.
• Even during the development phase, this model does not offer much scope for change.
• Even during the development phase, this model does not offer much scope for change.
• Testing is often delayed until completion, making large revisions more expensive.
• We are at high risk of uncertainty and risk due to unnoticed issues until the project is in its final phase.

Benefits of Agile

The following are the benefits of using Agile development method.

• This approach to software development is very realistic.
• Teamwork and cross-training are promoted.
• It is possible to develop and demonstrate functionality quickly.
• There is a minimum requirement for resources.
• Suitable for a variety of needs, whether fixed or variable
• Provides partial working solutions as soon as possible.
• A suitable model for environments that are constantly changing.
• A minimum or no planning is required.

Also Read: Citizen Development Can Pave the Way For Agility. Here’s how

Limitations of the Agile Model

Following are the limitations of Agile model.

• Complex dependencies cannot be handled by this method.
• There is a substantial risk of sustainability, maintainability, and extensibility.
• It needs an overall plan, an agile leader, and an agile PM practice to succeed.
• A strict delivery management process determines the scope, functionality, and adjustments to be made to meet deadlines.
• The team can be driven in the wrong direction when the customer is unclear.
• Due to the lack of documentation, there is a very high level of individual dependency.
• The lack of documentation may make it difficult to transfer technology to new team members.

Also Read: 6 Signs that your Legacy System is an obstacle for your business’s Digital Transformation!

Choosing the Right Software Development Approach: SDLC vs Agile

Project Complexity and Size

• SDLC: Best for large, complex projects with clear requirements.
• Agile: Ideal for projects of varying sizes with evolving requirements.

Customer Involvement and Feedback

• SDLC: Suited for fixed customer requirements.
• Agile: Emphasizes continuous customer collaboration and flexibility.

Project Flexibility

• SDLC: Rigid and sequential, less suitable for ongoing adjustments.
• Agile: Allows ongoing adjustments for flexibility.

Team Size and Expertise

• SDLC: Works well with large, specialized teams.
• Agile: Effective with smaller, cross-functional teams.

Project Timeline

• SDLC: Tends to have longer timelines.
• Agile: Promotes quicker deliverables with shorter iterations.

Risk Tolerance

• SDLC: Mitigates risks upfront, suited for low change tolerance.
• Agile: Embraces change, suited for higher risk tolerance.

Regulatory Compliance

• SDLC: Emphasizes documentation for strict compliance.
• Agile: Can meet regulatory requirements with additional documentation.

Previous Experience

• Consider your team’s familiarity with both methodologies.

Hybrid Approaches

• Consider combining elements of both SDLC and Agile for specific project needs.

Ultimately, the choice between SDLC and Agile should align with your project’s unique circumstances and requirements. You may also consult with stakeholders, project managers, and team members to make an informed decision. In some cases, a pilot project using one approach can help you determine if it’s the right fit before committing to it for larger endeavors.

Conclusion

Agile is a methodology, whereas SDLC is a process. SDLC has different methods within it, and Agile is one of them. In the SDLC, there are various methodologies, such as Agile, Waterfall, Unified Model, V Model, and Spiral Model. The selection of the methodology of traditional SDLC vs Agile depends on the understanding of digital transformation needs and size of the project. The same approach can also be applied to the STLC, called the Software Testing Life Cycle.

Frequently Asked Questions(FAQs)