Adobe first released the new Marketo Email Designer in January 2025. Through 2025 and into 2026, it steadily replaced the classic HTML-based editor as the default for most new email programs. If your team has not switched yet, it is worth understanding what changed — because the underlying model of an email in Marketo is now different, not just the UI.
The core building blocks: Structures, Modules, Fragments
The new Email Designer replaces the classic HTML template with three layered concepts:
- Structures — column/row layouts that define how an email is composed. Marketers can drag structures into an email and reorder them freely.
- Modules — reusable, template-defined content blocks (hero, product grid, CTA card). Modules live inside structures and expose editable fields to marketers.
- Fragments — cross-program reusable blocks like footers, headers, and legal disclaimers. Fragments replace the classic Snippet, and can be updated once to propagate across every email that uses them.
Why this matters
In the classic editor, an email was a single HTML template with editable elements. If you needed the same footer in 200 emails, you either accepted 200 copies or you leaned on a Snippet — which came with its own quirks. In the new designer, a Fragment is a first-class object. Update it once, and every consuming email inherits the change on next send.
Brand Themes and Content Locking
Two governance features arrive with the new designer that were painful to enforce before:
- Brand Themes — standardize fonts, colors, and spacing across all templates. Marketers can only choose from approved values.
- Content Locking — protect specific sections (legal text, brand elements) from being edited by campaign owners, while still allowing approved fields inside a locked module to change.
“For teams that have been fighting brand drift in every campaign for years, the combination of Fragments + Brand Themes + Content Locking is genuinely a category shift in how email programs are governed.”
AI Assistant and Adobe Express integration
The new designer bakes in AI assistance through the Content Accelerate feature — AI-generated subject lines, body copy suggestions, and image generation via Firefly and Nano Banana. Adobe Express is available inline for image editing, and the AEM asset repository is reachable from inside the editor for approved images.
What has expanded in 2026
- REST API support for programmatic email creation went from soft-release in Sep 2025 to officially supported in Feb 2026.
- Available inside Engagement, Default, and Event Programs (originally Email Program only).
- Conditional content now uses Velocity syntax (switched from Handlebars in Sep 2025).
- Image-to-Template — a PNG/JPG mockup can be converted into an editable email in a couple of clicks.
Limitations to plan around
The new designer is not classic-editor-with-drag-and-drop. There are real gaps as of mid-2026:
- No segment-based dynamic content yet — only attribute-based. Segment support is on the roadmap.
- No custom font support — only the standard font list.
- Some third-party tooling (Litmus integrations, Jeto templates, older HTML-heavy templates) still needs to be validated per instance.
Migration approach we recommend
Do not bulk-migrate. Start with 1–2 lower-stakes programs (internal comms, welcome series). Use Template Import for higher-stakes assets — do not rebuild from scratch. Run the new and classic versions in parallel for one to two send cycles to validate opens, clicks, and bounces before cutover. Keep the classic version as an inactive backup for rollback.
Once the migration approach is proven on two programs, roll out template by template — not team by team.