US tech start-up has raised $2.5m (£1.76m) in financing to help brands understand how people interact with their voice apps.

Pulse Labs' funding round was led by Madrona Venture Group, with participation from the Amazon Alexa Fund, Bezos Expeditions and Techstars Ventures.

The company was formed in 2017 to help brands understand how real people interact with their voice apps through a rigorous process of live testing and data analysis.

Using Pulse, voice app developers can quickly see how consumers want to interact with their app and get data on which prompts work and which do not.

The start-up has already assisted in the successful launch of more than 20 Alexa skills for top brands, and is extending its product to Google Actions in the coming months.

"Voice is the next-generation user interface and the future of how humans will interact with technology," said Maria Karaivanova, principal, Madrona Venture Group.

"When we met the Pulse team last year, we knew they were building something special. Their success in working with companies, brands and agencies prove there is a clear need to understand how real people interact with the ever increasing number of voice powered smart devices in their lives."

Abhishek Suthan, co-founder and CEO of Pulse, added: "Developing apps for voice is a significantly different process than app development on other platforms - as our workflows and interactions shift away from more traditional platforms and mediums, consumers have different expectations regarding how an app responds, and designers will need to understand this change.

"We're extremely happy to have the support of such a strong cohort of investors, and we’ll be leveraging their help to build a world class team and product for the leading voice services, starting with Alexa."

Pulse will use the financing to expand its product features and grow the team.