Sidecar has announced it’s shutting down at the end of the year. Company chief executive Sunil Paul explained in a Medium post (not the company’s official blog, strangely) that the move was intended to help pave the way so his team could “work on strategic alternatives and lay the groundwork for the next big thing.” All ride and delivery operations will shut down at 2 p.m. Pacific time on December 31, 2015.

One of the pioneers of the ridesharing movement years ago, Sidecar has failed to capitalize on it, losing ground to Uber and Lyft, both of which have raised hundreds of millions of dollars. But Sidecar’s approach was slightly different in that it allowed riders to select their drivers and didn’t have an issue with surge pricing, which many criticized its competitors for.

“Long ago we conceived of the technology that gave rise to the ride share movement,” wrote Paul. “And nearly four years ago we invented what is now known as ‘ride sharing’ with an app that connected riders with everyday drivers in their personal vehicle. People loved it. It was safe, convenient and affordable, and it quickly caught on.”

Sadly, what didn’t catch on was Sidecar.

Launched in 2012, one of the things that separated the company from Uber and Lyft was its understanding of regulatory issues. Paul told AllThingsD in an interview that his experience in the car-sharing space helped him plan ahead of issues that could (and eventually did) affect its competitors. It became one of the first so-called Transportation Network Companies (TNCs) to gain approval to operate at San Francisco’s airport, beating its rivals. But while it had many features similar to Uber and Lyft, the company just didn’t seem to gain any traction when it came to ridesharing.

Eventually the company pivoted away from just transporting people. Instead, it offered to be a Postmates-like courier service, delivering goods such as marijuana to customers. There were even reports that Sidecar had partnered with other services like Instacart to assist in transportation of goods. In February, it rolled out same-day deliveries to rival Postmates and other similar offerings, claiming at the time: “Same-day delivery will represent half of our business by the end of 2015.”

In total, Sidecar had raised $35 million in venture funding, backed by investors like Richard Branson, Mark Pincus, Lightspeed Venture Partners, Union Square Ventures, Lerer Hippeau Ventures, Google Ventures, Fenox Venture Capital, and Avalon Ventures.

Thank you for helping us reinvent transportation. I just published "so long Sidecar and thanks" https://t.co/YqjghrXA60 via @Medium — Sunil Paul (@SunilPaul) December 29, 2015

Sidecar customers will be receiving an email notifying them of the shutdown. Here’s what it says: