What is the software development process?
The software development process, often called the software development life cycle (SDLC), is the sequence of steps a team follows to plan, build and look after a piece of software. It exists so that everyone, client included, knows what is being decided when, what gets delivered at each point and how changes are handled.
Without an agreed process, the same problems turn up on almost every project: features nobody asked for, testing squeezed into the last week, and a launch date that moves because a decision made in month one was never written down. A process does not guarantee a good result, but it makes problems visible early, while they are still cheap to fix.
The 5 steps of software development
Every model below runs through these steps. The difference is whether they happen once, in order, or many times in small loops.
- 01Requirements. What the software must do, for whom, and how you will know it works. Output: a written scope, user stories or a requirements document.
- 02Design. How it will work and look: architecture, data model, integrations, wireframes and screen designs. Output: diagrams, a clickable prototype, an agreed tech stack.
- 03Build. Writing the code, usually in small pieces reviewed by another developer and merged into a shared repository.
- 04Test. Checking that each piece works on its own (unit tests), that the pieces work together (integration tests) and that the whole thing does what the client asked for (acceptance testing).
- 05Release. Deploying to the live servers or app stores, migrating data, and training the people who will use it.
Maintenance follows release and usually lasts longer than the project: bug fixes, security updates, hosting and small improvements. Ask about it before you sign, not after launch.
5 software development process models
1. Waterfall
Each step finishes before the next one starts: everything is specified, then designed, then built, then tested. It is the oldest model, usually traced back to a 1970 paper by Winston Royce (who, ironically, warned against running it strictly in one pass). Waterfall suits fixed-scope work with stable requirements and formal sign-off, such as a government system or a regulated integration. It fails when the client only learns what they want by seeing it, which describes most websites and apps.
2. Agile (Scrum and Kanban)
Agile is a set of principles from the 2001 Agile Manifesto: deliver working software often, welcome changing requirements, and keep the client involved. Scrum is the most common way to run it. Work happens in sprints of one month or less (two weeks is typical), each ending with a working increment and a review where priorities are reset. Kanban drops sprints and runs a continuous flow of tasks on a board, with a limit on how much is in progress at once; it suits support and maintenance work.
Agile suits products with changing requirements and a client who can give feedback every week or two. It is harder for clients who need a fixed price and fixed date before anything starts, unless the scope is treated as the variable.
3. Iterative
Build a rough version of the whole product, then refine it in passes. This is close to how design already works: sketch, wireframe, prototype, polish. Iterative development suits projects where the overall shape is known but the details are not. It is a poor fit where a rough version is risky in itself, such as anything that moves money.
4. Incremental
Build and release complete pieces one at a time: first the product catalogue, then checkout, then customer accounts. Each increment is finished, tested and usable. It suits ecommerce stores, portals and platforms that can launch with part of the feature list and grow. It does not suit products that only make sense once every part exists.
5. V-model
Waterfall with a test phase planned against every build phase: acceptance tests written from the requirements, integration tests from the design, unit tests from the code. Drawn on paper it forms a V. It suits safety-critical and compliance-heavy software, such as medical devices or industrial control. For fast-moving web work the paperwork costs more than it saves.
Software development models compared
| Model | Changes mid-project | Fixed price? | Client involvement | Typical use |
|---|---|---|---|---|
| Waterfall | Hard and expensive | Yes | Heavy at start and end | Fixed-scope, regulated systems |
| Agile (Scrum) | Expected | Per sprint or per team-month | Every sprint | Apps and products that evolve |
| Kanban | Any time | Usually a retainer | Ongoing | Support, maintenance, small changes |
| Iterative | Easy between passes | Sometimes | At each pass | Design-led websites and prototypes |
| Incremental | Between increments | Per increment | At each release | Ecommerce, portals, platforms |
| V-model | Hard | Yes | Formal reviews | Safety-critical software |
Which software development process should you choose?
Most real projects mix models. Use these questions to find the right mix:
- Do you know exactly what you need, and will it stay the same? Lean towards waterfall or a fixed-scope incremental plan.
- Will you learn what you need by using early versions? Choose agile or iterative, and budget for several rounds.
- Can the product launch with part of its features? Incremental gets you live sooner and earning while the rest is built.
- Is a mistake dangerous or legally costly? Add V-model style test planning, whatever else you use.
- Will the software need small changes every month after launch? Plan a Kanban-style maintenance arrangement from day one.
What the process looks like on our projects
We use a hybrid, because most clients want both a fixed quote and the chance to change their minds after seeing designs. Discovery and design are iterative: brief, wireframes, a clickable prototype, revisions until the client approves. The build is incremental against fixed-price milestones, each delivered to a staging site and reviewed before the next begins. Larger web applications move to sprints after the first release, when the backlog is driven by real users. For an example of a custom build rather than a theme, see the React site we made for the logistics company S-Line.
Two habits matter more than the model name. First, every decision that changes scope is written down with its effect on time and cost. Second, the client sees working software early, on a staging link, rather than screenshots at the end. If you are deciding whether a freelancer or a company should run your project, our freelancer vs agency comparison covers what each can realistically manage.
Questions to ask a software company about its process
- What do I receive at the end of each phase or sprint, and how do I review it?
- How are changes priced once the project has started?
- Who writes and runs the tests, and will I get to do acceptance testing on a staging site?
- Who owns the code repository, and will I have admin access to hosting and domains?
- What happens after launch: response times for bugs, security updates, and the monthly cost?
- Which tools will we use to communicate and track tasks (for example Jira, Trello, ClickUp or GitHub Projects)?
Sources
- The Scrum Guide (2020), Ken Schwaber and Jeff Sutherland: Sprints are fixed-length events of one month or less (scrumguides.org)
- Manifesto for Agile Software Development (2001) (agilemanifesto.org)
- Winston W. Royce, "Managing the Development of Large Software Systems" (1970), the paper usually cited as the origin of the waterfall model
Common questions
- What are the 5 steps of software development?
- Requirements, design, build, test and release, followed by ongoing maintenance. Every process model runs through these steps; they differ in whether you do them once in sequence, as in waterfall, or repeat them in short cycles, as in agile, iterative and incremental development.
- What is software development?
- Software development is the process of planning, designing, writing, testing and maintaining computer programs, from websites and mobile apps to internal business systems. It covers the whole life of the software, not only the coding.
- Which software development process is best for a website?
- Usually an iterative design phase followed by an incremental build against a fixed quote. Pure waterfall tends to produce sites the client does not like at the end, and pure agile makes a budget hard to commit to in advance.
- Can agile work with a fixed budget?
- Yes, if scope is the variable: a fixed number of sprints, with the client choosing what goes into each one. What cannot be fixed is scope, price and date all at once.
- What is the difference between iterative and incremental development?
- Iterative development refines the whole product in passes; incremental development finishes it one piece at a time. A painting done in layers is iterative, a house built room by room is incremental, and most real projects mix both.
- What is the easiest software development model?
- Waterfall is the simplest to understand and to price, because each step happens once. It is only easy in practice when requirements are clear and stable; when they are not, the late changes make it the hardest.
