Peer Richelsen

Peer Richelsen is co-founder of Cal.com, the open-source scheduling platform he launched with Bailey Pumfleet after failing to find a self-hostable Calendly alternative. Cal.com's about story starts with his earlier hiring company Lean Hire and a Google search for "calendly open source" that returned nothing worth shipping.

The missing open-source Calendly

Richelsen has written that while building Lean Hire he noticed how little open infrastructure existed around scheduling. He started Calendso, then incorporated with Pumfleet as Cal.com, Inc., with a long-horizon mission of connecting a billion people through scheduling by 2031.

Open scheduling as company mission

As co-founder he remains the public voice for Cal.com's open, customizable booking infrastructure for individuals, teams, and developers embedding scheduling. The product story stays on ownership and extensibility: run it your way rather than rent a closed calendar link forever.