Question to the HM Treasury:

To ask Mr Chancellor of the Exchequer, what proportion of HMRC's (a) transactions and (b) transaction value came through application programming interfaces in each of the last 12 months.

During 2016/17 HMRC processed 2.3bn transactions, 95% of which were digital. Where Application Programming Interfaces (APIs) were available as an option they made up 80% of service transactions. APIs currently account for about 12% of all digital transactions.

HMRC is currently unable to supply the transaction value that came through APIs. This is because a significant number of internal API transactions using the API platform do not have a monetary transaction value e.g. API transactions supporting customer service voice biometrics.