No. Its not a Government App. Its a product of National Payments Corporation of India (NPCI) which is a Section 25 company under Companies Act 1956 (now Section 8 of Companies Act 2013).
NPCI has ten promoter banks namely, State Bank of India, Punjab National Bank, Canara Bank, Bank of Baroda, Union Bank of India, Bank of India, ICICI Bank, HDFC Bank, Citibank and HSBC. The Board constitutes of Shri Balachandran M as the Chairman, Nominee from RBI, Nominees from ten core promoter banks, two Independent Directors and Shri A. P. Hota, Managing Director and Chief Executive Officer, NPCI.
Ref: National Payments Corporation of India (NPCI) About us page