IT Glossary
What is waterfall?
The cascade model: project phases flow in sequence — requirements, design, build, test, deliver — each finished before the next one begins.
Waterfall borrowed its shape from construction and engineering, where nobody pours foundations while still arguing about the number of floors. The phases flow downwards: all the requirements first, then the complete design, then the build, then testing, then delivery, each phase closed and signed before the next opens, with plan, budget and deadline fixed at the start. Its appeal is genuine and explains its longevity: predictability on paper, since you know from the outset what you get, when and for how much, which is the comfort every procurement budget looks for; complete documentation; clear roles and responsibilities. For certain projects it really is the right choice — requirements that are genuinely stable and fully known, regulated contexts demanding phase documentation, or combined hardware and software work where changing course midway does not exist. Its structural risk, though, is exactly what produced the entire agile movement: feedback arrives at the end. The client sees working software only after months, when the inevitable discoveries — this is not what we pictured, the market moved, the specification meant different things to different readers — cost the most, because everything is built and change now means demolition rather than adjustment.
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Why it matters for your business
Predictability where requirements are certain
With genuinely fixed specifications such as a regulation, a defined integration or a migration, a complete plan with closed price and deadline is exactly right.
Documentation as a by-product
Signed phases naturally produce specifications, architecture and manuals, valuable at audit, for compliance work and when a project changes hands between teams.
Contracts that are simple to administer
Fixed deliverables, clear acceptance criteria and payments per phase form the model procurement departments understand without needing anything translated.
Frequently asked questions
Waterfall or agile for our project — the short answer?
It turns on the certainty of the requirements. If you know them completely and they will not change — a regulation, a fixed technical specification, a defined migration — waterfall on that slice is legitimate. If you will discover them along the way, which is the near-universal case for business applications, iterative delivery with regular demonstrations is safer. The honesty test for knowing exactly what we want: have three people in the company describe the finished product separately, then compare the descriptions.
Fixed-price, fixed-deadline quotes look safer. Where is the catch?
In who pays for the discoveries. A fixed price on incomplete requirements is defended either through change requests, where every additional realisation becomes a billed amendment — the flexibility iterative delivery includes and this model sells separately — or through literal delivery of an imperfect specification, where you receive what you wrote rather than what you needed. The safety is real only as far as the specification is: on solid requirements a fixed price is fair, on guessed ones it is an illusion with a rate card attached.
Can we combine a fixed plan and budget with delivery in stages?
Yes, and that hybrid is the healthiest arrangement on the market: a sequential frame with serious initial analysis, architecture, an agreed total budget and horizon, containing iterative execution inside it — fortnightly demonstrations and priorities adjustable within the budget. You get the financial predictability approval requires and the continuous control that prevents a surprise at the end. Ask for it in the contract as fixed budget and objectives, content managed iteratively, working software demonstrated regularly.
Let’s talk about your project
Message us on WhatsApp or send an email — you talk directly to a developer.
office@northdan.com · +40 752 070 247