ParkWhiz, a startup that’s something of an Open Table for available parking spots, is adding $5 million in new equity to its recently announced Series D round. The new funds come from strategic investors Amazon’s Alexa Fund, Alate Partners, Chaifetz Group and Purple Arch Ventures. Combined with the earlier round led by NewSpring Capital, the total raise was $25 million.

The parking service has expanded over the past couple of years across the U.S. and Canada, and now counts 40 million customers who have used ParkWhiz to find parking in garages and lots. The service today powers transactional parking services for hundreds of partners, including sports teams and venues, events, travel providers, airlines, hotels, automotive OEMs and navigation systems within their own apps and sites, it says.

For Amazon, the value in partnering with ParkWhiz has to do with its adoption of voice-based computing.

Using Amazon’s Alexa virtual assistant, ParkWhiz customers can find and reserve parking spaces using only their voice.

This investment makes even more sense when aligned with Amazon’s recent efforts to bring Alexa to vehicles as part of its larger agenda to capture market share in voice computing.

In September, the company announced a slew of new Alexa devices, including Echo Auto, which plugs into a car’s infotainment system to provide voice access to things like traffic reports, news, shopping lists, smart home control and third-party skills — such as the one ParkWhiz offers.

“The Alexa Fund was created to support companies building compelling products and services that leverage voice technology, and ParkWhiz is a fast-growing company that fits that profile perfectly,” said Paul Bernard, director of the Amazon Alexa Fund, in a statement. “Customers love using its Alexa skill to find and reserve parking spaces using just their voice, and we’re excited to support them as they pursue deeper integrations with Alexa at home and on the go.”

In addition to voice access to parking, ParkWhiz offers a mobile app as well as the option to book over SMS or through an embedded solution in the car.

ParkWhiz says the strategic investors were added to the round for more than their capital, but rather their ability to add value as it expands customer reach, inventory, and its “Arrive” parking network.