Bulletproof Button Builder
Generate an email-safe CTA button with Outlook VML fallback. Paste the output directly into your HTML email.
Live Preview
Email Development Tools
Browser-based utilities built for email developers. Generate bulletproof buttons, preview preheader text, check contrast ratios, estimate email size, and build UTM-tracked links without sign-up.
Toolkit
Interactive Tools
Everything runs locally in your browser. Nothing gets sent anywhere.
Preheader Preview
See how subject line and preheader text truncate across common inbox widths.
Character count: 0
Email Size Estimator
Paste your HTML to estimate size. Gmail clips emails larger than roughly 102 KB.
Size status
Paste HTML to see the estimate.
Contrast Checker
Check WCAG contrast ratio between text and background colours.
Sample Text
The quick brown fox jumps over the lazy dog.
AA Normal = 4.5:1 for regular-sized text. AAA Normal = 7:1 for regular-sized text. AA Large = 3:1 for large text (24px+ regular or 18.66px+ bold). AAA Large = 4.5:1 for large text.
UTM Builder
Build campaign-tracked URLs for your email links.
Email Coding Guides
In-depth guides covering the trickiest parts of email HTML development.
Dark Mode in Email
How email clients handle dark mode and what you can do to control rendering.
Coding for Outlook
VML, conditional comments, and workarounds for Microsoft's rendering engine.
Email Accessibility
Semantic structure, ARIA roles, and colour contrast for inclusive emails.
FAQ
Frequently Asked Questions
Yes. Everything on this page runs in the browser and does not require sign-up or external API calls.
Yes. It generates VML markup inside conditional comments so Outlook desktop gets a styled button while modern clients get the normal HTML version.
Preheader text is the snippet shown after the subject line in many inbox previews. Optimising it helps give recipients a stronger reason to open the email.
Very large emails can be clipped in Gmail, which can hide footer content, legal links, and tracking pixels.
Yes. The generated output is yours to use. If you need custom development or QA, you can link this section to your project enquiry flow.
Need custom email development?
We hand-code HTML emails and test across major clients. Use the tools above for quick checks, then get in touch when you need production-ready builds.
