This is SoftBank's first investment in an Indian company this year.
True Balance was set up in 2014 by South Korean expatriate Cheolwon (Charlie) Lee.
The app gives balance check, call log, data pack assessment, and recharge service for prepaid accounts on Android smartphones.
"The True Balance application retires the old, inconvenient way of checking your current mobile balance," said JP Lee, Director of SoftBank Ventures Korea, adding “True Balance is built for "centralizing and analyzing your balance log data, enabling it to be the most valuable as a potential mobile wallfor the future."
"We have already crossed the 2 million downloads mark this March and are looking to achieve a new milestone of 10 million downloads in the next 9 months," said Cheolwon.