Vikram Singh, product manager for a diabetes-software start-up called Glooko, received a somewhat unexpected email from Amazon Web Services last month.

The company invited Singh and several other health developers in the space to participate in its upcoming Alexa Diabetes Challenge, which comes with a $125,000 grand prize sponsored by drug maker Merck.

The goal is to get developers to build apps that use Amazon's Alexa voice-recognition software to help people with diabetes manage the disease. "Communicating through voice, rather than just on a screen, has the potential to empower patients to change habits and improve their overall wellbeing," a blog post reads.

Glooko ended up submitting an app that would act as a personal health assistant for people with Type 2 diabetes. Alexa would ask basic questions on a daily basis, like "What have you eaten today?" or "Did you take your meds today" and set up a weekly call with a health coach.

Diabetes is a particularly popular initial target for technology companies, including Alphabet and Apple, as the disease is expensive to manage and requires varying degrees of tracking, among other reasons.

Apple is working on a novel sensor that can continuously and non-invasively track glucose, while Alphabet is developing a contact lens to track blood sugar without pricking the skin and has secured partnerships with life sciences companies like Sanofi and Dexcom.

"We've heard a lot from Apple and Google, especially about hardware," Singh told CNBC. "We were more surprised to hear from Amazon."

Diabetes isn't the only opportunity for health developers intrigued by voice-recognition software. Boston Children's Hospital developed its own Alexa-based app called KidsMD that issues advice to parents when their kids catch a fever.

"From a business-model perspective, I think that Amazon Alexa could do a lot to bring their Echo devices into the enterprise chronic-care management space," said Singh. "That takes it away from just being a consumer device."