Show HN: Countdown Builder – Create Custom Countdown Timers for Email Campaigns

I built Countdown Builder as a lightweight way to add urgency to email campaigns.

Most ESPs don’t provide native countdown timers, and existing solutions are either clunky, expensive, or not very customizable. Countdown Builder lets you:

Design a countdown timer (fonts, colors, styles)

Preview in real-time

Generate a snippet to embed directly into your email

Use cases: flash sales, product launches, webinars, or any campaign where showing “time left” works better than just saying it.

I’d love feedback from this community on:

Edge cases I might have overlooked (email client compatibility, etc.)

Features you’d expect if you were to use this

Any gotchas you’ve faced embedding dynamic content in email

This is my first attempt at building a tool in this space, so I’m very open to ideas and critique.