OptinMonster - OptinMonster helps to convert abandoning website visitors into subscribers and customers.

MJML - The open source framework for responsive emails

Sleeknote - Set up lead capture forms on your website in minutes. No coding required. Sync your new email leads with your favorite email service provider. Try for free.

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.

Poptin - Create engaging and high converting website pop ups and contact forms in minutes. With Poptin, you get access to a feature-packed conversion rate optimization toolkit that converts more website visitors into email subscribers, leads, and customers.

Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.