Introduction
To ensure a secure, performant, and consistent email experience, Open Email Standards permit only a defined set of external CSS frameworks, JavaScript libraries, and CDN providers. These resources have been pre-approved based on their reliability, cryptographic delivery over HTTPS, and alignment with security and performance best practices. By restricting usage to these trusted sources, the standards help prevent unauthorized tracking, dynamic injection, and other risks associated with unverified third-party content.
Approved Libraries and Resources
CDN Providers
Font Providers
CSS Frameworks
JavaScript Libraries
Embed Platforms
Approved Utilities
- The list of approved resources may be expanded or updated. For the latest version, please visit: openstandards.email/resources