Cronofy, the U.K. startup that offers a calendar API to help businesses and their customers synchronise calendars, has raised a $1.6m seed round led by Firestartr alongside Amsterdam-based venture capital firm henQ.

“We’re the plumbing that connects apps and services with peoples calendars,” explains Cronofy founder Adam Bird. “Our customers are SaaS providers”.

Cronofy customers include flight search engine Skyscanner, Applicant Tracking Systems (ATS) providers and health professionals booking platform Zesty.

Richard Muirhead, Firestartr co-founder and chairman, says “Synchronising schedules has become critical for many millions more people, driven by smart phones, the gig economy and crazy calendars. Software developers crave easy ways to embed great functionality into their apps and websites, so we really like Cronofy’s developer-driven route to market.”