Invision - Prototyping and collaboration for design teams
Stripo - Stripo is an all-in-one email design platform. We enable our clients to build emails of any complexity, including interactive AMP emails, really fast and easy.
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
MJML - The open source framework for responsive emails
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
BeeFree.io - Bee is MailUp's drag-&-drop editor for responsive design emails.