Definition
Email linting automatically checks your email HTML for structural errors, unclosed tags, and common compatibility problems before you send. It is the first line of quality control in a pre-send workflow.
Linters flag issues that render tests and human review can miss, such as unclosed tables, invalid nesting, and markup that clients will strip. Fixing these early prevents broken emails and wasted sends.
Linting catches structural errors before they reach recipients, saving time and preventing broken emails. It validates markup and flags client-stripping risks. Pairing it with render tests gives complete coverage.
What a Linter Checks
Linters validate markup, nesting, and some client compatibility rules.
They are not a substitute for render testing, which checks appearance.
Why It Matters
Linting catches structural errors before they reach recipients, saving time and preventing broken emails. Understanding it makes pre-send QA faster and more reliable.
Best Practices
- Run an HTML linter in your pre-send checklist.
- Fix structural issues before render testing.
- Accept that linters flag many, but not all, client quirks.
- Automate linting in the build step where possible.
- Pair linting with render tests for full coverage.
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Related Glossary Terms
Above the Fold in Email
Above the fold in email refers to the content visible to a recipient before they scroll, a critical area for first impressions and primary calls to action.
Accessible CTA (Email)
An accessible CTA is a button or link coded with sufficient colour contrast, visible focus states, descriptive screen-reader text, and a minimum touch target of 44×44 pixels.
Adaptive Design
Adaptive design in email uses predefined layouts that adjust to specific device or client widths, rather than fluidly resizing to every possible screen.
AI-Generated Content in Email
AI-generated content in email is copy, images, code or subject lines produced by artificial intelligence tools to speed up campaign production and testing.
Alt Text
Alt text is the written alternative to an image in an email, displayed when images are blocked, slow to load, or consumed by screen readers.
Autoplay Video in Email
Autoplay video in email refers to the limited ability to play video content automatically when an email is opened, using specific client-supported techniques.
Frequently Asked Questions
Markup validity, nesting, and some client compatibility rules. Linting catches structural errors before they reach recipients, saving time and preventing broken emails.
No, pair it with render tests in real clients. It validates markup and flags client-stripping risks.
Before every send, ideally in the build step. Pairing it with render tests gives complete coverage.
No, some client quirks only show in render tests. Linting catches structural errors before they reach recipients, saving time and preventing broken emails.
Run the linter as part of your build or pre-send process. It validates markup and flags client-stripping risks.