The verdict in three sentences
UAT (user acceptance testing) is the phase where the client verifies that the delivered site is compliant with the brief before accepting it and paying the balance. In 2026 it runs 2 to 4 weeks, relies on a written test log and acceptance criteria, and comes with a 3 to 6 month warranty and a 10 to 20 % retention of the price until sign-off. A project manager who accepts without a test log signs a blank cheque: defects found afterwards become chargeable.
The test types to run during UAT
Serious UAT is not just "click everywhere". It covers several test families, each with its criteria. Here is the reference test plan for a B2B web project in 2026.
| Test type | What it checks | Acceptance criterion |
|---|---|---|
| Functional | Every feature in the brief | 100 % of Must cases pass |
| Compatibility | Browsers and mobiles | 3 browsers + 2 screen sizes |
| Performance | Load speed | Lighthouse > 90, < 2 s |
| Accessibility | WCAG standards | AA level targeted |
| Security | Common vulnerabilities | No critical vulnerability |
| Technical SEO | Tags, sitemap, redirects | SEO checklist validated |
| Content | Copy, images, links | Zero broken link, up-to-date |
Acceptance conditions and the retention
Acceptance is decided on facts, not impressions. Defects are graded by severity, and only some block acceptance. Here is the reference grid and the impact on payment.
| Defect severity | Definition | Effect on acceptance | Retention |
|---|---|---|---|
| Blocking | Key function unusable | Acceptance refused | Balance retained |
| Major | Significant degradation | Acceptance with reserves | 10-20 % retained |
| Minor | Cosmetic flaw | Acceptance granted | Fixed under warranty |
| Enhancement | Outside brief | Separate quote | No effect |
| Post-delivery warranty | Defects found later | Free correction | 3-6 months |
The retention (10 to 20 % of the price) is released when reserves are lifted, usually 2 to 4 weeks after launch. The workmanship warranty (3 to 6 months) covers defects not detected during UAT. These durations are a 2026 ballpark.
Mini case study
Sarah, project manager at a logistics firm in Singapore, leads UAT on a client portal delivered for USD 20,000. She demands a 45-case test log and a 15 % retention, i.e. USD 3,000 held until sign-off.
UAT reveals 3 blocking and 12 minor defects. Thanks to the retention, the vendor fixes the blockers in 6 days before receiving the balance. Without a test log or retention, those 3 defects would have surfaced in production and been fixed as a change request, at an estimated USD 1,700 and two weeks of client-side disruption.
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FAQ
How long does UAT take in 2026?
Between 2 and 4 weeks depending on site size, including correction cycles. Rushed UAT in a few days lets defects through that reappear in production.
What is a test log?
It is the document listing every test case to verify, with the expected result and the status (pass / fail). A mid-size B2B portal has 40 to 80 test cases. Without it, acceptance is subjective and unenforceable.
What retention should I demand?
Between 10 and 20 % of the price, held until reserves are lifted. This retention is the best lever for fast fixes: the vendor is paid when the site is compliant, not before.
How long is the post-delivery warranty?
3 to 6 months depending on the contract. It covers, free of charge, defects present at delivery but detected afterwards. Beyond that, corrections fall under the support contract.
Which defects block acceptance?
Only blocking defects (key function unusable). Major ones allow acceptance with reserves, minor ones are fixed under warranty. This grading avoids blocking launch over a cosmetic flaw.
Let's scope your project. Send us your brief and target delivery date, and we will build a clear test log and acceptance criteria, with a retention. 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.
