Purpose: Mosaico is an open source email template builder for designing responsive email templates.
Responsive templates: The site says its responsive, tested templates work with all major email clients and devices.
Customization: Users can personalize the overall theme and customize individual element styles.
Image handling: The editor supports drag and drop image uploads and automatically resizes images to fit available space.
Editing controls: Mosaico provides a global undo and redo system.
Custom templates: Mosaico supports custom templates through a template language that can make an HTML design work with the editor.
Template driven editing: The project README says templates define which content and styles can be edited in Mosaico.
Open source license: The official site says Mosaico is distributed under the GPL license and links to its complete codebase on GitHub.
Deployment: The project README documents building and running Mosaico locally and deploying it through a web server such as Apache PHP or Django.
Integrations: The project README says Mailtrain supports email editing via Mosaico and lists CiviCRM among open source projects using it.
Image hosting limit: The site says hotlinking images from mosaico.io is disallowed and asks users to download and host images themselves.
Support: The site directs users who need support to its linked support guidance and says feedback email is not for support requests.
Audience: The site invites developers, template authors, end users, and UI/UX designers to provide feedback and suggestions.
Maker: The site says Mosaico is brought to users by Italian email marketing firm VOXmail.it.
Price from: Free

Where it ranks on Freedom251

Best Email Template Software in 2026#7 of 26

Is Mosaico yours?

Claim it for free: prove the domain, then correct facts, plans and screenshots. An editor reviews every change.

Claim it free Promote Mosaico

Sources

mosaico.email· checked 4 Oct 2026
github.com/voidlabs/mosaico/blob/master/README.md· checked 4 Oct 2026