Set Email Content

Updates the email content of an automation's send email action.

The content is replaced in full, and is live for subsequent runs of the automation once the call returns. Replaced in full means anything left out of content is cleared, so omitting the preview text or a default placeholder value removes it rather than keeping what was stored. The one exception is editorType, which describes the content type rather than being part of it.

This operation doesn't preserve draft translations: after the update, the email content and every existing draft translation are published and become live.

A draft automation is the exception: its content is updated in the draft only, and nothing is published. The content, in every language, goes live when the draft automation is published.

There's no revision to pass and no concurrency check: the last write wins, and two callers updating the same email at once silently overwrite one another.

The most reliable way to update content is to first retrieve it with Get Email Content and modify the result, rather than building content from scratch. WEB content in composer.composerDataJson is a proprietary structure. It's checked before storage and rejected with CONTENT_NOT_PUBLISHABLE when it isn't a JSON object, has no regions, or has a region with no type, an unsupported type, no data, or data missing the objects its type requires. To create content from scratch, use the MJML or HTML editor type. If the content may later be opened in AI Composer, see Update Composer for the MJML components it can edit and the limitations of other components.