> For the complete documentation index, see [llms.txt](https://mifos.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mifos.gitbook.io/docs/payment-hub-ee/overview/secondary-identifier-storage-and-registration.md).

# Secondary Identifier Storage and Registration

Documentation on the storage of secondary identifiers (e.g. MSISDN) in Fineract

Document the registration API and process

Retrieve the secondary identifier (MSISDN) for an account (identified by external account ID) API