Litmus is an email marketing tool for designing, testing, monitoring and personalising email campaigns. It also offers deliverability insights, collaboration and review tools, competitive intelligence and contact data quality features. It works alongside the customer's email service provider through integrations with platforms such as Mailchimp, HubSpot and Salesforce Marketing Cloud, and is accessed as an online service. The company's site now describes the product as part of Validity Engage.
Litmus Software, Inc. is headquartered in Boston, Massachusetts, in the United States, and its privacy page refers to CCPA and CPRA compliance. Validity, Inc., also based in Boston, acquired Litmus in 2025. The Validity trust centre refers to a Data Processing Addendum and a list of sub-processors, but does not state where customer data is hosted. A European organisation should therefore expect US ownership and processing, and should request hosting locations and the DPA before use.