2026 Optimizely CMS 13 (PaaS) release notes

Optimizely CMS 13 is a major release that upgrades the platform to .NET 10 and introduces a modern content management experience built around headless delivery, visual authoring, and deep integration with Optimizely Graph. CMS 13 makes Optimizely Graph and Opti ID mandatory components included in your CMS 13 license, establishing the foundation for cross-product composability within the Optimizely One ecosystem.

This release delivers value across the platform:

• For content editors – Visual Builder replaces on-page edit as the default editing experience, providing a unified interface for pages, blocks, experiences, and media. New content templates, content variations, auto-translation, and the new Content Manager streamline day-to-day content operations.
• For developers – A new C# (.NET) SDK for Optimizely Graph offers a familiar fluent API for querying content, ASP.NET MVC support in Visual Builder removes the Graph dependency for rendering, and content type contracts enable flexible content modeling through .NET interfaces.
• For administrators – Redesigned application management replaces site definitions, and new tools for license management and scheduled job monitoring improve operational visibility.

Features and enhancements

Visual Builder

Visual Builder is the default editing experience in CMS 13, providing a unified interface for creating and editing pages, blocks, experiences, and media assets. It replaces on-page edit (OPE), which is disabled in CMS 13. See Visual Builder for more information.

• Unified content editing – Edit pages, blocks, media, experiences, and sections in a single interface with autosave, interactive property highlighting, synchronized preview, and consolidated content creation dialogs. 
• Experiences and sections – Build layout structures with a data model that separates layout from content. Editors can create experiences and sections from scratch, add rows and columns, and copy and paste layout structures between sections. Administrators control which block types are available as elements or sections. 
• Shared blocks in experiences – Drag and drop shared blocks into experiences, edit them in-context, and have them automatically inlined when indexed to Optimizely Graph for complete content delivery. See Shared blocks for more information.
• Templates and blueprints – Create, export, and import content templates with predefined property values and layouts. Manage templates and blueprints centrally in Settings with search, filtering, and pagination. See Manage blueprints and Blueprints for more information.
• ASP.NET MVC rendering – Render Visual Builder content server-side using tag helpers (epi-outline, epi-component, epi-grid, epi-row, epi-column) and HTML helpers, without requiring Optimizely Graph. See Configure Visual Builder for setup instructions.
• Custom elements – Define and save custom element types directly in the Admin UI using existing editors and fields, without requiring code deployment.

Content Manager

CMS 13 introduces Content Manager, a new search-first interface for content navigation powered by Optimizely Graph. Content Manager gives editors faster content discovery and a more efficient workflow for managing large content libraries. See Manage content with Content Manager for more information.

• Graph-powered search – Find content fast across all content types with Graph-based search, filtering by content type, status, and language.
• Customizable views – Toggle columns on or off, reorder them, and browse image and PDF assets in a grid view with orientation-aiding backgrounds.
• Details panel – Inspect content items in a slide-out panel with thumbnail, title, properties, and an Edit shortcut, without leaving the list.
• Content sources – Load content from CMS and external content sources configured through Optimizely Graph using a left-hand navigation panel.
• Page creation and in-context editing – Create CMS pages directly from Content Manager with blueprint selection, and edit content in an embedded dialog without navigating away.
• Content and CMP Library pickers – Select images and assets directly within Visual Builder using the Content Manager picker and CMP Library picker.

Content variations

CMS 13 introduces content variations, letting you maintain multiple published variations of the same content item in the same language. This enables experimentation and personalization scenarios, helping you optimize content performance through data-driven testing. See Create content variations for more information.

• Delta-based storage – Variations store only explicitly modified properties, optimizing storage and management.
• Independent lifecycle – Each variation has its own version history and publishing lifecycle, with approval workflow integration.
• Edit view management – A Variations dropdown in the toolbar lets editors create, switch between, and manage variations with full autosave support.
• Real-time preview – The preview URL contains all necessary information for the frontend to fetch and render the correct variation version.
• Promote to original – A Copy changes to Original option lets editors apply successful modifications from a variation back to the primary content instance.
• Graph indexing – All content variations, including unpublished drafts, are indexed to Optimizely Graph with unique identifiers for discovery in previews and experiments.

Content editing

CMS 13 includes several content-editing improvements that enhance the day-to-day workflow for editors.

• Scheduled publish date in Version gadget – Added the scheduled publish date to the version status display, helping editors confirm when scheduled content will go live.
• Increased default upload size – Increased the default file upload size to align with Microsoft's recommended settings for Kestrel and Azure. Improved error messaging for upload failures.
• Restricted file upload by extension – Added a whitelist of allowed file extensions across all upload methods, preventing the upload of potentially unsafe files.
• Increased external link character limit – Increased the external link character limit from 255 to 2,000 characters, letting editors save complete URLs without truncation.
• Content GUID display – Added the content GUID alongside the content ID in Edit view, providing a consistent identifier for content items.
• Blocks renamed to Shared Blocks – Renamed "Blocks" to "Shared Blocks" across the user interface to better distinguish reusable blocks from inline blocks.
• Migrated top area actions – Moved content management actions from the All Properties top area to the in-page Settings tab for a cleaner editing interface.

Multi-language and translation

CMS 13 introduces new multilingual content management capabilities with redesigned translation workflows and machine translation, reducing the time and effort required to manage content across multiple languages. See Translate content for more information.

• Global language context switching – Added the ability for content creators to change the global language context, with the UI dynamically adjusting to reflect content availability and creation permissions.
• Enhanced translation workflows – Added the ability to translate content from multiple initiation points (context menu, toolbar ribbon, language selector). The Translate Content dialog box lets editors copy content structure, duplicate source content, or start empty.
• Auto-translation – Machine translation preserves the original structure including page hierarchies, content areas, and blocks. The editing context automatically switches to the target language upon completion.
• Draft translation – Added the ability to translate draft content (pages, blocks, experiences) without requiring prior publication.
• Translatable content export – Added export of translatable content in a human-readable format (JSON) for use with external translation providers, respecting Visual Builder and content structures.
• Redesigned Language Selector – Redesigned the Language Selector to display all available languages split into two sections: languages with existing branches and those without. Clicking an untranslated language opens the Translate Content dialog box.
• Browser language preferences – Updated UICultureLanguageCode so that browser language preferences are correctly applied when UseBrowserLanguagePreferences is enabled.

Optimizely Graph C# (.NET) SDK

CMS 13 introduces the Optimizely Graph C# (.NET) SDK, providing a fluent API for querying content directly from C# code, similar to Optimizely Search & Navigation. The SDK offers a familiar, strongly-typed querying experience that simplifies the transition from Optimizely Search & Navigation to Optimizely Graph. See Optimizely Graph C# SDK for more information.

• Fluent API – Build and execute Optimizely Graph queries with field-level search including boosting, skip and limit pagination, facet support, and total count retrieval.
• Strongly-typed results – Deserialize query results into selected POCO types or strongly-typed content models.
• Caching – Cache Optimizely Graph query results with support for custom cache eviction policies.
• Authentication – Single-key authentication by default with an opt-in for Basic authentication per query, including support for IPrincipal and options to include deleted content.
• Tracking – Track Optimizely Graph queries for analytics and optimization.

CMS REST API

CMS 13 introduces a full REST API for content modeling, content management, and more. The API is included by default through AddCms(), with OAuth client configuration available through appsettings.json or environment variables on DXP. See the API reference documentation for more information.

DAM integration

CMS 13 introduces embedded Optimizely Digital Asset Management (DAM) integration as a separate NuGet package (EPiServer.Cms.DamIntegration.UI), enabling editors to browse, search, and select DAM assets directly within the CMS editing interface. Optimizely Content Management System (CMS) offers three ways to work with Digital Asset Management (DAM) assets. Each suits different workflows and levels of DAM integration.

• Embedded DAM
• Content Manager
• DAM asset picker (through a DAM integration package)

Application and site management

Applications replace the site definition feature from CMS 12, providing a streamlined interface for managing in-process and headless websites and other types of applications. This simplifies multi-site management and aligns configuration with modern hosting patterns. See Applications for more information.

• Create, edit, and delete applications – Added a dedicated interface with validation, editable names, and API IDs.
• Automatic migration – Implemented automatic migration of SiteDefinition settings to in-process web applications when upgrading to CMS 13, including site-specific assets, hostnames, and wildcard hostname handling.
• Default application – Added the ability for administrators to designate a default application, replacing the previous wildcard behavior.
• Application-specific assets – Added functionality that lets content editors upload and select assets unique to each application. When enabled, headless applications generate unique URL segments to distinguish their assets, while in-process applications retain existing URLs.
• Expanded host types – Added expanded host type support. Headless applications support Primary, Preview, and Media hosts. In-process applications support Default, Primary, Media, Edit, RedirectPermanent, and RedirectTemporary hosts.
• Updated terminology – Renamed Website and Channels to Application and Applications throughout the UI and APIs.

Preview for headless sites

CMS 13 introduces configurable preview routing for headless websites, giving frontend teams control over how preview URLs are generated and managed. See Enable live preview for more information.

• Custom preview routing – Configure preview URLs in Settings with predefined tokens (Context, Host, Key, Locale, Path, Segment, Version).
• Live preview management – Enable or disable preview per application and manage fallback and content-type-specific routes.
• Reusable preview tokens – Preview token validation verifies the principal's permissions to the routed content rather than validating the token's content reference.
• Preview request handling – Load specific preview versions, bypass query cache, and render HTML attributes for frontend preview interactivity.
• Automatic configuration – Existing applications are automatically updated with correct default preview routing values during upgrade.

Content modeling

CMS 13 adds new content modeling capabilities, improving flexibility and reducing package dependencies. See Create contracts for more information.

• Content type contracts – Added support for defining content type contracts as .NET interfaces inheriting from IContentData. Developers can specify that a content type is a contract using a property on ContentTypeAttribute, and contract types can be used in AllowedTypesAttribute.

Admin and configuration

• Cloud license management – Added a dedicated view at Settings > Cloud License with a tooltip displaying active server names for each URL and a detailed dialog on click. See Manage cloud licenses for more information.
• Third-party licenses page – Added visibility into open-source licenses of npm packages delivered to the client browser in CMS edit mode.
• Scheduled job hang detection – Added a log indicator for jobs that appear to be running but have stopped responding, helping administrators identify and resolve stalled jobs. See Scheduled jobs through code for more information. See also Scheduled jobs through the UI.
• Plugin Manager removed – Removed the Plugin Manager UI and its backend components. Scheduled jobs and custom property types no longer use the obsoleted EPiServer.PlugIn system.

Security and data integrity

• File extension filtering on import – Added file extension filtering during data import. Blobs with extensions not in the allowed whitelist are blocked, with a message listing skipped files.
• Permission checking on user deletion – Added IsSupported enforcement during user delete operations, preventing bypasses of custom UIUserProvider restrictions.

Import and export

See Export data and Import data for more information.

• Enhanced error visibility – Improved import error visibility so that error messages during package import remain visible on the page for administrators.

Framework

• Upgraded to .NET 10 – Upgraded CMS 13 to the .NET 10 runtime. See Upgrade to CMS 13 for migration guidance.
• Optimizely namespace – Updated module URL segments to use the Optimizely namespace (for example, /Optimizely/Optimizely.Cms.UI.Admin/) instead of the EPiServer brand.
• DAM packages renamespaced – Moved DAM integration packages from the EPiServer namespace to the Optimizely namespace.

Deprecated and removed features

For a complete list of breaking changes, see Breaking changes in CMS 13.

• Optimizely Search & Navigation – Deprecated Optimizely Search & Navigation. CMS 13 and future releases no longer support Optimizely Search & Navigation implementations. Implement search with Optimizely Graph or a third-party search provider. See Migrate from Optimizely Search & Navigation for guidance.

• On-page edit (OPE) – Disabled on-page edit by default in CMS 13 in favor of Visual Builder. See Visual Builder for the replacement editing experience. A developer needs to set OnPageEditing to true in appSettings.json to enable on-page editing in the user interface (UI).

  services.Configure<CmsFeatureOptions>(options =>
   {
       options.OnPageEditing = true;
   });

• Plugin Manager – Removed the Plugin Manager from the Admin interface.

Coming next for CMS 13

• Opal tools and agents
• Web MCP – access to Optimizely tools and instructions from anywhere.
• Blueprint support for all content types
• CMS+CMP integration; manual now, automated later.
• DAM  – Asset migration from CMS 12 to CMS 13 for current DAM customers, and asset tracking.
• JS SDK
• Content Delivery API support
• Migration path improvements  
  • Simplified project creation for existing CMS 12 Optimizely Graph customers.
  • Claude AI skills and documentation on Optimizely Search & Navigation to Optimizely Graph migration
• The following apps (add-ons)
  • Language Manager
  • Forms
  • Content delivery API, and will then ONLY support existing CMS12 capabilities, no net new features added (for example, no Visual Builder support)