Exchange rate for export of services

for rates

https://www.cbic.gov.in/Exchange-Rate-Notifications

date of invoice rate of exchange for raising invoice.

For services, then link is given to Generally Accepted Accounting Practices (GAAP), which inturn links to RBI rates. 

RBI website > archives > rates as per dates

But this is not being updated on daily basis. 

In such cases can refer CBIC rate notifications itself. Although, it is for goods, can be used for services too. Available in bottom right corner of the CBIC official website. Link cannot be shared as this changes frequently.