This is the third edition of our review. We first published it in September 2025 and updated it in May 2026. This Fall 2026 edition adds our latest test results.
Since its early-2025 launch, the new Marketo Engage Email Designer has become a far more polished drag-and-drop editor, with reusable fragments, brand themes and a cleaner editing experience. Its API, however, still trails the classic editor for programmatic control. With each major Adobe release, we retest it against Jeto so you know what’s improved and whether it’s ready for your programs.
This edition covers the biggest milestones so far, including the public Email Designer REST API (February 2026) and Conditional Content inside fragments (May 2026). It also covers our latest test of the full Jeto workflow, from Launcher to Campaign to the cloned program.
Compatibility Status: The new Email Designer is a big improvement for managing Marketo assets and is fully compatible with Jeto, except for module (fragment) controls, which aren’t supported yet.
The Designer was limited when it first came out (see our initial review), but it has improved steadily. For Jeto clients, the biggest benefit is being able to create and edit Marketo email templates in a drag-and-drop interface. That reduces the need for custom, costly template coding.
The good news: some Marketo API bugs and limitations remain, but we’re confident we can support emails built in the new Designer in Jeto. We can’t yet confirm whether module deletion and controls will be part of the first release. Our team will keep working on fragment controls for future releases.
Public REST API support for the Designer arrived in February 2026. It was a crucial milestone, but because it isn’t backward compatible with the classic email API, it still takes real integration work.
First, here are the major improvements to the Designer since it launched.
January 2025: The drag-and-drop Designer launched in the January release with fragments and content locking. At first it required Adobe IMS, worked only in Email Programs, and had no public API.
March 2025: It became available in Engagement, Default and Event Programs.
May 2025: Designer emails could be cloned, and role-based access control got more detailed permissions.
June 2025: Conditional Content was added for dynamic personalization. It used Handlebars at first and was later temporarily disabled.
July 2025: Custom CSS gave users more design control, partly closing the gap between pure WYSIWYG and the code-based classic editor. Emails could be moved between programs, and programs containing Designer emails could be deleted. Firefox support, a read-only permission and per-email branding domain and IP settings were also added, and the Adobe GenStudio integration was announced.
August 2025: Bug fixes and speed improvements arrived, including email previews that load up to 60% faster, fixes to template rendering and content locking, and Designer emails in email performance reports.
September 2025: Dark Mode support, AI Assistant permissions and comments on assets were added. Adobe also announced that Conditional Content scripting would switch from Handlebars back to Velocity, which Marketo users know better.
October 2025: Conditional Content (now on Velocity) and A/B testing came back on par with the classic editor. A Template Importer (beta) for classic templates, Brand Themes and an image-to-HTML converter were also added.
January 2026: Emails, templates and fragments could be organized in folders. Fragments got thumbnails, and multi-level bullets were added. Conditional Content reached parity with the old Dynamic Content, and the AI Assistant could take brand assets in the prompt.
February 2026: The Email Designer REST API arrived, the long-missing piece. Folder actions caught up with the classic editor: share, archive, share across workspaces and drag-and-drop. AI image generation added Nano Banana alongside Firefly.
March 2026: An Outlook rendering fix shipped, along with Advanced HTML Mode for small HTML/CSS edits. Quick Actions (Duplicate, Delete, Move, Create/Edit Draft) and editable components in fragments were added, plus Manage Brands (beta) and Brand Score Checker.
May 2026: Conditional Content started working inside fragments.
Adobe has also improved the documentation along the way. There’s a new Experience League article, Feature Comparison – Old editor vs New Designer, an updated Email Designer knowledge base, as well as the Email Template (New/V2) Email (New/V2) and Fragments (New/V2) API documentation
Our Experiments
Our testing approach was simple:
Step 1 – Build a Marketo program template with new emails
Build a new email template from the library
Create a test program
Build two emails: (a) one from a template, (b) one directly in the Email Designer, with no template
Tokenize the program and emails
Step 2 – Create a Launcher and a Campaign from the new program
Resync our Jeto instance to fetch the new program
Create a new Launcher and generate the preview
Create a campaign and: (a) preview all assets, (b) edit content (one field of each type, including images), (c) preview the changes, (d) send a sample, (e) submit and review the cloned program, (f) run the test campaign from Marketo
Test Results
API Bug and Workaround
Right away, we found a bug in the Marketo Asset API. The Get Emails (browse) endpoint doesn’t return the email header values (Subject, From Name, From Address, Reply-To, Preheader). We’ve reported it to Adobe and hope it gets fixed soon. [Add your workaround in one sentence.]
Editing Content, Previews and Samples
Once we handled the API errors, editing content from the Jeto form was easy and worked as expected for every token type, with previews generated as we edited. Sending email samples also worked as expected.
Module Editing Not Yet Supported
In the new Designer, modules have been replaced by customizable fragments. Marketo added Fragment endpoints to the Asset API (v2) in 2026, but they manage fragments as standalone assets. They don’t yet cover inserting fragments into an email or editing a fragment’s content inside an email. So for now, we’ve put Jeto’s module-editing feature for the new Designer in the “maybe later” bucket.
Campaign Processing (and Program Clone)
The program was cloned successfully and kept the new emails, the program structure and the values Jeto filled in. [Add the result of step 3f.]
User Interface and User Experience
The new Designer gives you a great deal of control over email editing. Highlights:
AI generation: We like to test AI everywhere, and generating email content from prompts is a great use of it and a blast to try.
The right-side panel for email properties.
The left-side panel with editing controls and new widgets for the navigation tree, links, fragments and direct access to assets.
Programmatic Controls (API Integrations)
The biggest drawback of the new editor is still its lag in providing programmatic API controls. Partner applications like Jeto, and custom integrations, depend on those controls to work with Marketo emails.The table below summarizes our observations on these aspects as of November 2026.
D = documented on Experience League
T = observed in testing
U = not documented, needs testing
Capability | Classic editor (v1 API) | New Email Designer (v2 API) |
Create an email from a template | Supported (D) | Supported: |
Create an email with its own content | Limited to classic templates (D) | The create body accepts |
Read the email’s content |
| The docs show only metadata. In testing, the GET response includes the full HTML in |
Update email headers and settings | Supported (D) | Supported: partial update, “all properties are optional” (D) |
Update the email’s content or HTML | Per section, or full HTML once the email is unlinked from its template (D) | Supported: send the new HTML in |
Reorder, add, duplicate or remove content blocks (modules, snippets or fragments) | Dedicated endpoints: | No dedicated endpoints. Likely possible by editing the HTML, either moving whole sections or moving the |
Approval lifecycle | Approve, unapprove, discard draft (D) |
|
Clone, delete and dependency lookup | Clone and delete (D) |
|
Reusable content blocks | Snippets (D) | Fragments: create with |
Update a reusable block’s content | Supported for snippets (D) | Create accepts |
Templates | Full content and structure endpoints (D) | Create, update, approve, clone, delete, |
Content schema documentation | Documented (D) |
|
Other Limitations
Gmail Clipping: Adobe community reported the new designer produces much heavier HTML), in a context where Gmail cuts off any email whose HTML is over about 102 KB and shows a “View entire message” link
Outlook Tables: Adobe community also reported possible table breaks in Classic Outlook Outlook Desktop App (no surprise here..). So test your layouts in classic desktop Outlook for Windows, which is still the hardest client for table-based designs. Adobe’s March 2026 release improved the Designer’s Outlook rendering, but testing is still essential.
Conclusion
Nearly two years after launch, the new Marketo Email Designer has become a robust tool. Conditional content, custom CSS, a public REST API and full folder and quick-action parity have largely closed the gap with the classic editor. That especially benefits teams that want to edit and customize templates themselves. We’ve put Jeto’s module-editing feature for the new Designer in the “maybe later” bucket. the team will soon review the recent API updates and limitations related to controlling fragments inside an email to determine if/when we could enable marketers to control email modules from Jeto.
If you have additional questions on the new Email Designer or need help in mirgating your email templates from Email 2.0 to the new Email Designer, please reach out to your Customer Success Manager!