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User Acceptance Testing: How to Plan and Run UAT That Actually Catches Problems
User acceptance testing is the last check that software meets real business needs before it goes live. This guide explains how to plan UAT, choose testers, write scenarios, manage defects and decide on sign-off — especially when working with an external development partner.
TopicsQA and Software TestingDedicated Teams and OutsourcingProduct Design and Discovery
Key takeaways
- UAT confirms that software supports real business processes for the people who will use it; it is not a substitute for QA testing by the delivery team.
- Types include business acceptance, operational acceptance, contract acceptance, regulatory acceptance, and alpha and beta testing.
- Good UAT starts at the beginning of the project with acceptance criteria written alongside requirements.
- Use realistic scenarios, data and environments, and real users from each affected role.
- Agree sign-off criteria in advance — for example, no open critical or high defects and all key scenarios passed.
On this page
User acceptance testing (UAT) is the stage where the people who will use or own a system confirm that it does what the business needs. It is often squeezed at the end of a project, rushed and treated as a formality — which is why many problems are only discovered after go-live.
What UAT is — and is not
UAT checks that the system supports real business processes, in conditions close to production, for the people who will use it. It is not the place to find basic functional defects; those should be caught by developers and QA earlier. If UAT finds many basic bugs, earlier testing is not working.
Types of acceptance testing
| Type | Focus | Typical participants |
|---|---|---|
| — | — | — |
| Business acceptance | Supports business processes end to end | Business users, process owners |
| Operational acceptance | Backup, recovery, monitoring, support processes | Operations and support teams |
| Contract acceptance | Meets contractual criteria | Client and supplier representatives |
| Regulatory acceptance | Meets legal and compliance requirements | Compliance, legal, auditors |
| Alpha testing | Early internal testing of a product | Internal users |
| Beta testing | Real customers in real conditions | Selected customers |
Large projects often include several types.
Who should take part
- End users from each role — not only managers — who know the real workflows and edge cases.
- Process owners who can decide whether behaviour is acceptable.
- A UAT coordinator who plans, tracks progress and manages defects.
- The delivery team available to answer questions and fix issues quickly.
Writing acceptance criteria and scenarios
Acceptance criteria should be written with requirements, not invented at the end. Good scenarios:
- describe a realistic business situation from start to finish;
- use realistic data, including difficult cases;
- state the expected outcome clearly;
- cover the main path and important exceptions.
Example: “A customer service agent processes a return for an order containing a discounted item and a gift card payment. The refund is split correctly between the original card and a new gift card, the stock is returned to the correct warehouse and the customer receives a confirmation email.”
A step-by-step UAT process
- Plan: scope, schedule, participants, environment, data and sign-off criteria.
- Prepare: scenarios, test data, user accounts and training for testers.
- Check readiness: QA complete, environment stable, known defects listed.
- Execute: testers run scenarios and record results, with support available.
- Triage defects daily: severity, priority and decisions on fixes.
- Retest fixes and run regression on affected areas.
- Decide: compare results with sign-off criteria; document accepted risks.
- Sign off and record outstanding issues with owners and dates.
Defect severity and sign-off
| Severity | Example | Typical sign-off rule |
|---|---|---|
| — | — | — |
| Critical | Cannot complete a core process; data loss | Must be fixed |
| High | Core process requires a difficult workaround | Must be fixed or explicitly accepted by the business owner |
| Medium | Inconvenience with an easy workaround | Can be scheduled after go-live |
| Low | Cosmetic issues | Backlog |
Agree rules before UAT starts to avoid disputes at the end.
UAT with an external development partner
When software is built by a partner, UAT often doubles as contract acceptance. Protect both sides by:
- agreeing acceptance criteria and the UAT period in the contract;
- sharing scenarios early so the partner can test against them;
- keeping a shared defect log with agreed severity definitions;
- distinguishing defects from change requests clearly.
Our guide to the hidden costs of the wrong software partner explains why clear acceptance terms matter.
Common mistakes
- Leaving UAT until the final week with no time to fix issues.
- Using unrealistic or empty test data.
- Testers without training or time allocated in their schedules.
- Treating UAT as functional testing because QA was skipped.
- No agreed sign-off criteria.
- Recording feedback in emails and chats instead of a tracked log.
Frequently asked questions
How long should UAT take?
It depends on scope, but plan time for at least one full cycle of testing, fixes and retesting — often one to three weeks for a significant release.
Can UAT be automated?
Parts of acceptance testing can be automated as regression tests, but UAT’s purpose is human judgement about business fitness.
Who signs off?
The business owner accountable for the process, based on agreed criteria and with input from users.
What if users request changes during UAT?
Log them separately as change requests and decide whether they are needed before go-live.
Sources and methodology
Facts in this article were checked against the sources below on 6 November 2026. Directory data (ratings, review counts, rate bands and team sizes) changes over time and is shown as published on the date accessed. Illustrative examples are labelled as such and are not quotes.
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