The 15 most common bugs found in beta tests (and how to catch them early)

The 15 most common bugs found in beta tests, from verification emails in spam to layouts that break on small phones, with how to catch each one early. By betatest.ing team · September 24, 2026 · 7 min read.

Key takeaways

Most beta bugs cluster in a few places: email delivery, forms, auth edge cases, layout on small screens and error handling.
Each of the fifteen has a cheap check you can run before testers see the product.
Environment and account state cause many "cannot reproduce" bugs; test with aged, messy accounts, not fresh ones.
Console errors and broken links are the leading indicators of deeper problems.
Run the repeatable checks automatically on every build so testers find new bugs, not the same ones.

1. The verification or reset email never arrives

The most common beta blocker, and the one teams most often "test" by checking that the send call returned 200. The email lands in spam, in Gmail's promotions tab, or nowhere because the domain lacks SPF, DKIM and DMARC records, or because the staging environment uses a sandboxed email provider that only delivers to verified addresses.

Catch it early: Send verification, password reset and invite emails to real accounts at Gmail, Outlook and iCloud and check the inbox, not the logs. Verify your DNS records with your email provider's checker. Our onboarding email testing guide has a full checklist.

2. Signup breaks on an edge-case email or password

Plus signs in email addresses rejected. Uppercase letters in emails treated as a different account. Password rules enforced on the client but not the server, or the other way round. Leading and trailing spaces not trimmed.

Catch it early: Try [email protected], an uppercase variant of an existing email, a password with spaces and emoji, and a very long password. Check the error messages say what is wrong.

3. Social login and email login create two accounts

A user signs up with email, later clicks "Continue with Google" using the same address, and gets a brand-new empty account. Or the reverse: Google login silently takes over an existing email account without verification.

Catch it early: Create one account each way with the same address and observe. Decide on the intended behavior (merge, block with a message, or link) and test it on both paths. See login and password reset testing.

4. Buttons that do nothing after an error

The form submits, the server returns an error, the button stays disabled or the spinner spins forever. The user has no idea whether to wait or retry. Often caused by an error path that never resets loading state.

Catch it early: Force a failure (disconnect the network, submit invalid data that passes client validation, kill the API) and confirm the UI recovers and tells the user what happened.

5. Forms accept nonsense

Negative quantities, dates in the past for future bookings, a phone number field that accepts letters, a required field that is only required on the client. Validation gaps that produce bad data and support tickets later.

Catch it early: For every form, submit empty, submit the maximum, submit the wrong type, and submit via a direct API call bypassing the client. The form validation testing guide has a test task you can run as is, and the test case generator will produce cases for a specific form.

6. Layout breaks on a small phone

Tables that force horizontal scroll, modals taller than the viewport with the Save button off-screen, fixed headers that cover content, text that overflows its container at 320–375 pixels wide. Looks fine on the developer's iPhone Pro Max.

Catch it early: Test at 360 and 375 pixels wide on a real device or an accurate emulator. Pay special attention to modals, date pickers, tables and long names. See responsive design testing.

7. The keyboard covers the input on mobile

Related but distinct: on phones the on-screen keyboard hides the field being typed in, or the Submit button, and the page does not scroll to compensate. Common in chat-style inputs and multi-step forms.

Catch it early: On a real phone, tap into the last field of every form and confirm you can see what you type and reach the button.

8. Broken links and 404s inside the product

Links to help pages that moved, a footer link to a page that never existed, an email link with a staging URL, a "Back" link that goes to the wrong place. Each one is small; together they read as neglect.

Catch it early: Crawl the product (logged out and logged in) and check every link. The free website checker does this for public pages; the broken links and console errors guide covers logged-in areas.

9. Console errors nobody looked at

A page that looks fine but logs a stream of exceptions, failed requests and React warnings. Console errors are the leading indicator of the intermittent bugs testers will report in a week with no steps.

Catch it early: Open developer tools on every page during testing and treat red lines as bugs, even when the page appears to work.

10. Session expiry handled badly

A tester leaves a tab open overnight. In the morning, every click silently fails, or the app throws them to login and loses the form they were filling in, or worse, an expired session still shows cached private data.

Catch it early: Shorten the session timeout in staging to a few minutes and use the app across the boundary. Confirm the user is told, redirected sensibly, and returned to where they were after logging in again.

11. Permissions leak between roles or tenants

A member can see an admin-only page by typing the URL. An invited user sees another workspace's data in a dropdown. An API endpoint returns records for any ID, not just the caller's. These are the most serious bugs in the list and the easiest to miss, because developers test as admins.

Catch it early: Test every screen and every API call as the lowest-privilege role, and as a user from a second workspace. Try IDs that belong to someone else. The OWASP Top 10 lists Broken Access Control as the most common web application security risk for a reason.

12. Empty states and first-run screens that do not exist

A brand-new account lands on a dashboard with an empty chart, "undefined" in a heading, or a blank page with no hint of what to do. The team never sees this because their accounts are full of data.

Catch it early: Create a fresh account for every round of testing and go through every screen with no data. Each should say what the screen is for and offer the first action.

13. Payments work in the happy path only

Test card succeeds, so billing is "done". Then a real customer's card is declined, or requires 3D Secure, or the user closes the tab after paying but before the redirect, and the account is charged but not upgraded.

Catch it early: Use your provider's test cards for decline, insufficient funds and authentication required. Close the browser mid-flow. Pay twice quickly. Confirm webhooks are what upgrade the account, not the redirect. Our payment flow testing guide has the walkthrough.

14. Slow pages and heavy assets

A dashboard that takes eight seconds on a throttled connection, an unoptimized hero image of several megabytes, a third-party script that blocks rendering. Testers describe this as "it feels broken" rather than "it is slow".

Catch it early: Load key pages with the network throttled to a slow 4G profile and look at what loads first. Google's web.dev performance guides explain what to measure and why, and the website performance check guide turns it into a test task.

15. Copy that is wrong, inconsistent or still placeholder

"Lorem ipsum" in a footer. A button that says "Sign up" on one page and "Register" on another. An error message with a variable name in it. A date shown as 10/03 that means March 10 to half your users. Testers notice every one and it erodes trust in everything else.

Catch it early: Read every page aloud, in order, as a stranger. Search the codebase for placeholder strings. Pick one term per concept and stick to it. See copy and typo review.

The pattern behind the list

Almost every bug above comes from one of three gaps:

Environment gaps: the team tests on fast machines, large screens, modern browsers and accounts full of data.
Path gaps: the team tests the happy path and skips errors, cancellations, expiry and empty states.
Role gaps: the team tests as the admin and never as the member, the guest or the stranger.

Closing those gaps deliberately before human testers arrive means the beta surfaces new problems instead of these fifteen.

Running these checks automatically

Every item on this list is repeatable, which makes it a good candidate for an AI beta tester. betatest.ing runs these checks as part of a normal test: it uses your product in a real browser and on phones at small widths, tries the unhappy paths, watches the console, follows every link, and files each problem as a bug with steps, severity, an annotated screenshot and a recording. Scheduled runs after each deploy keep the list from coming back.

Start for $1 and find out how many of the fifteen your product has right now.

Related guides

Each ends with a test task you can send to your AI beta tester.

All beta testing guides

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