AccuZIP - AccuZIP Postal Software and Data Cleansing For Direct Mail Marketing
Addressy - Addressy is address verification software that captures and verifies addresses on websites.
Melissa Data Quality - Melissa helps companies to harness Big Data, legacy data, and people data (names, addresses, phone numbers, and emails).
ClickToAddress - ClickToAddress offers APIs for address lookup and verification.
Loqate - The Standard in Global Address Verification
Addressify - Addressify is an API that allows developers to implement address verification, validation and autocomplete for Australia in their apps.