Show HN: I built a text-based birthday reminder app (739 paying users, $550 MRR)

I bought the birthdays.app domain a few years ago and decided to build a simple birthday app, just text message reminders.

I had hacked together a duct-tape version for myself a couple years prior (using zapier + google sheets), and found it useful. It was a pain sifting through Facebook birthdays (90% irrelevant), and I found the text reminders simpler than a calendar.

The app has been slowly growing since 2023, and is now up to 739 paying users (mostly on the $9/yr plan, with a few paying $3/yr).

Earlier this year, I built a Google Calendar integration to automatically sync birthdays to the app. My goal is birthday reminders without the baggage a normal "social" app would have such as ads, engagement bait, etc.

I call it an app, but there's actually no app to download. Users log in via phone number + sms login code, then input birthdays manually, via text, or via Google Calendar.

At the moment, US users receive SMS messages (which are cheaper to send in the US), while other countries receive WhatsApp text reminders.

The app uses Twilio to text users (both SMS + WhatsApp) and Stripe for payments.

I'm hoping to build more features (iPhone contacts sync, easier birthdays importing) while also making video content that celebrates strangers' birthdays (such as, going to a farmers market with an "is it your birthday?" sign).

Thank you for reading, I'm open to any thoughts or ideas around the app!