AddressLab · Guides
Email Field Validation: Syntax, Required Values and Delivery
First published: · Chrome · 2026-10-24
A browser email field can check syntax and an empty required value; it cannot show that a mailbox exists or receives mail. In this test, the format sample was accepted, removing @ set typeMismatch, and an empty required field set valueMissing. AddressLab supplies no inbox, verification code or sending service.
For signup and notification QA teams separating input validation from delivery. We ran the three built-in cases in the English-only email field tool in Chrome. The Chinese and Japanese versions of this article explain the same English interface; no localized email tool is implied.
Run the three input cases without sending mail
Open the email field demonstration. Select Format sample and then Check field. Repeat with Missing @ and Required field empty. These actions read the local input’s validity; they do not submit a registration or contact a mail server.
| Input | valid | typeMismatch | valueMissing |
|---|---|---|---|
alex.morgan10@gmail.com | true | false | false |
alex.morgan10.gmail.com | false | true | false |
| (empty) | false | false | true |
The initial common-domain sample is a format example and may coincide with a real person’s mailbox. Do not send to it or use it for an actual account. Keep outbound mail disabled if you copy any random sample into staging.
What the accepted case establishes
This result comes from an input with type=email and required. It is not a complete implementation of your signup policy. A server might additionally enforce a length limit, allowlist or account rule. Test that contract separately and ensure its error is shown to the user; do not infer server acceptance from this demonstration.
Read the failure flag rather than one generic error
typeMismatch identifies the malformed sample; valueMissing identifies the empty required field. Logging only “invalid email” loses the difference between a missing value and a syntax error. The demonstration uses noValidate so it can display these flags in its own result panel; that does not disable reading the browser validity state.
The observations are specific to this Chrome build. Repeat relevant cases in your supported browsers and on the server. A required browser field is not an authorization or anti-abuse boundary.
Choose data for the task you actually need
| Task | Suitable data | Evidence to keep |
|---|---|---|
| Input, display or CSV mapping | A reserved test-domain sample; no mail sent. | Exact input, field validity and saved/exported value. |
| Template rendering | A local preview or approved staging mail sink. | Template ID, variables and rendered links. |
| Delivery/verification link | A QA mailbox or mail-testing service under your control. | Trigger ID, provider acceptance, arrival time and link behavior. |
| Account recovery | A controlled test account in an approved test environment. | Token lifecycle and completed recovery result without production credentials. |
The Synthetic Test Data Generator uses addresslab.test email examples for fixtures. IANA lists .test as special-use; it is not a public disposable inbox. Keep outbound delivery disabled and use a controlled receiver for any delivery test.
A separate delivery run needs separate evidence
- Create or select a controlled QA recipient and confirm the staging environment’s outbound routing.
- Trigger the intended event once and record its event/message identifier, recipient, timestamp and expected template.
- Check the received content and link destination, then exercise the product’s expiry, repeat-use and account-state rules.
- Distinguish provider acceptance from inbox arrival and successful completion of the product action.
These are proposed checks for your own system. We did not send a notification, receive an email or open an account-verification link in this test. No delivery success should be claimed from the three validity rows above. For the surrounding address payload, use the address data round trip.
Sources and test scope
AddressLab used AI assistance to organize this guide and checked it against the recorded browser operations and the primary references below. Tests ran on 24 October 2026 against a local production build in isolated Chrome. External advertising and analytics requests were blocked during functional QA. These observations do not prove address assignment, delivery, mailbox ownership or tax outcomes.