Investment in recruiting chatbots jumped from 2014 through this year, and more than $100 million in funding has been raised for the four most significant chatbots alone, according to the “Introduction to Chatbots” report released by Staffing Industry Analysts.

“Recruitment chatbots, in particular, have attracted significant investment and a number of large staffing firms have made strategic investments into chatbot providers or developed their own tools,” according to the report.

One chatbot, Eightfold, has raised $51.8 million; it’s the most raised among the recruiting chatbots, although it has additional functionality. Mya Systems raised $32.4 million, the second-most.

In a separate prediction, Gartner forecast that by 2021, more than half of enterprises will spend more each year on chatbots and their creation than on traditional mobile app development.

Chatbots are essentially robot customer service agents, capable of handling routine human tasks/interactions. Some use artificial intelligence. However, the common denominator among chatbots is use of an electronic interface to communicate with individuals (chat), collect data from the conversation and use the data to complete a task or update records without human intervention.

“Our report lists 30 firms in the chatbot space as well as information on how to select a chatbot,” said John Nurthen, SIA’s executive director of global research. “These range from rudimentary electronic forms to globally deployed, enterprise-level conversational AI recruiting bots.”

The report is available to SIA corporate members.