Builder Guide
Monaco advanced JSON mode
Edit the canonical page document directly in Monaco with the same validation and publish fences.
Every page has one canonical JSON document. Monaco (advanced) edits that same document directly for builders who need precise structural control. Puck remains the primary editor; switching editors does not fork the page or create a second source of truth.
What the validator protects
Every block carries a stable identity that the template upgrade system uses to merge changes safely. If a raw edit would remove or duplicate a block identity, the save is blocked with error E021 until you explicitly acknowledge the loss. This isn't bureaucracy — losing those identities means future template upgrades can no longer match your customized blocks to their upstream versions.
Acknowledging E021 is permanent for the affected blocks. They will be treated as brand-new content in every future template upgrade. If you're not sure, cancel and ask what the edit is removing.
Returning to Puck
You can switch back to Puck only when the document parses and passes the editor's structural checks. A malformed edit cannot enter the visual editor, save as a valid draft, or reach the live page. The same edit lease, expected version, validation, and exact-draft publish rules apply in both editors.
When to use it
- Bulk find-and-replace across a large page
- Pasting a block structure between pages
- Inspecting exactly what a block is configured to do
Page JSON describes presentation and approved bindings; it does not encode a user's authorization. DataRoles, Locations, field rules, and action checks are evaluated by runtime services for the signed-in person.
Exporting the application definition
Builders can export the versioned JSON documents and JSON Schema contracts that define an application's pages and workflows. The package preserves the portable application definition - including component configuration, approved bindings, workflow steps, and version metadata - without exporting live credentials.
This is different from a customer data export. The application-definition package describes how the product behaves; an account data package contains only the authorized organization's records and related artifacts, while a whole-SaaS backup contains the app's databases and must remain restricted to authorized operators. Together with the continuity runtime, the two packages support migration or recovery outside BuildWithHQ. See Business continuity and application portability.
For everyday layout work, Puck is faster and safer. Reach for Monaco when you need surgical precision.
Capability review: 2026-09-14. For exact current technical availability, use the generated API Map and first-class module inventory.