The verdict in three sentences
Acceptance testing is not an end-of-project formality: it is the insurance that keeps a critical bug from reaching your users. A defect caught in acceptance costs about 10 times less than the same defect in production (outage, emergency hotfix, damaged image). In Amsterdam in 2026, reserve 10 to 20 % of the project budget for QA, target 60 to 80 % test coverage, and require a signed acceptance report before any go-live.
How much to invest in QA and why
The QA budget is not a cost, it is risk reduction. Here is how it breaks down and what it prevents.
| QA item | Share of project | Deliverable | What it prevents |
|---|---|---|---|
| Unit tests | 4-8 % | 60-80 % coverage | Silent regressions |
| E2E tests (Playwright) | 3-6 % | Automated critical scenarios | Broken flows in prod |
| Functional acceptance | 2-4 % | Signed acceptance report | Gaps vs specification |
| Load tests | 1-3 % | Load-handling report | Collapse at peak |
| Post-delivery warranty | included | Fixes 1-3 months | Hidden costs after go-live |
The cost of a bug follows a well-documented rule: the later it is found, the more expensive it is. In design it costs 1, in development 5, in acceptance 10, in production 100 (support, emergency, lost trust).
Test plan and acceptance criteria
Serious acceptance follows criteria written BEFORE development, not improvised at the end. Each feature has its own definition of "done".
| Stage | Typical duration | Goal |
|---|---|---|
| Writing acceptance criteria | Before dev | Define "done" unambiguously |
| Automated e2e tests | Continuous | Lock down key flows |
| Internal acceptance (team) | 1 week | Fix before showing the client |
| Client acceptance (UAT) | 1-2 weeks | Real business validation |
| Acceptance report | 1 day | Confirm conformity, trigger final payment |
| Post-delivery warranty | 1-3 months | Fix residual defects |
Total acceptance runs 2 to 4 weeks depending on scope. Playwright e2e tests automate critical scenarios (login, payment, order creation) and replay on every deployment, which stops regressions from returning.
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Mini case study
Sophie, project manager at a logistics SME in Amsterdam, oversees an order-tracking app at 90,000 EUR. The vendor proposes to "skip acceptance to hit the deadline". She refuses and imposes 15 % QA budget (13,500 EUR). Result: 23 defects caught in acceptance, including 3 blockers on delivery-time calculation. Fixed before prod, they would have cost ~10x in production (client outages, weekend hotfix): an avoided risk estimated above 40,000 EUR, for a QA investment of 13,500 EUR. Immediate ROI, before counting reputation preserved.
FAQ
What percentage of the budget should go to QA? Budget 10 to 20 % of the project depending on criticality. Below 10 %, you transfer risk to production, where each bug costs far more.
What test coverage should I target? A realistic target is 60 to 80 % on critical business code. Aiming for 100 % is counterproductive: cost explodes for marginal gains on trivial code.
What is an acceptance report? A signed document listing tested features, remaining defects and their severity. It confirms conformity to the specification and usually triggers the final payment.
Why automate e2e tests? Because they replay on every deployment in minutes, preventing regressions. A Playwright test checking the payment funnel protects you on every future update.
What does the post-delivery warranty cover? Usually 1 to 3 months of free fixing of defects missed in acceptance. It is the safety net after go-live, distinct from paid new features.
Let's scope your project. Tell us your application's criticality and your sensitive flows, and we will cost a test plan with target coverage and acceptance report, QA budget 10-20 % of the project. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
