Dropbox Sign, formerly HelloSign, is an eSignature and document-workflow product founded in 2010 and acquired by Dropbox, Inc. in 2019 for $230 million in cash, Dropbox's largest purchase at the time. It is a product of publicly traded Dropbox (NASDAQ: DBX) and suffered a security breach in April 2024 in which attackers accessed customer emails, usernames, phone numbers, hashed passwords, API keys, OAuth tokens and MFA data.