Loqate - The Standard in Global Address Verification
Smarty - Smarty provides address validation, autocomplete, geocoding and reverse geocoding services covering addresses in over 240+ countries.
ClickToAddress - ClickToAddress offers APIs for address lookup and verification.
Lob - A simple API to integrate print & mail solutions into your applications.
SAP Data Management - Sap Data Management is a flagship enterprise information management solution that facilities the organizations to manage data quality, migration of data, text analytics, and interconnectivity with both SAP and non-SAP system.
AddressZen - Effortless Address Lookup.