Appointment scheduling SaaS with deep CalDAV support and multi-calendar integration — a Calendly alternative built as a solo side project for 4 years.
Rafał Muszyński built Harmonizely as a side project while working full time, spending four years iterating and growing its user base. The tool stood out with native CalDAV support (Google Calendar, Outlook, iCloud, Zimbra, Zoho) where Calendly struggled. In June 2021, SimplyBook.me — a competitor in the scheduling space — acquired Harmonizely and rebranded it as SimplyMeet.me, integrating it into their suite of scheduling products. Terms were not disclosed.
Building a solid niche alternative to a dominant player (Calendly) as a side project for 4 years is a viable path to acquisition. The buyer was a strategic competitor wanting the user base and feature set, not a financial buyer hunting multiples.