There are no immediate plans to allow the reconciliation of bank statement lines via the Xero API. We are keen to get your feedback on this. If it is a feature you would like to use, please vote (and optionally leave a comment on your own specific use case) in our Uservoice forum here. Voting will ensure you will be notified of any developments.
Bank Statement lines import
We will look to allow developers import bank statement lines to bank accounts in the future. To show your support and get updated as we make progress, vote here.
Bank Statement Report
There is a bank statement report which can be accessed via the Reports endpoint and allows you to retrieve the details of statement lines that have been imported into a Xero organisation.