Update localized content
Partially updates journey message content. Optional content must be exactly one of mjml, html, text, or payload as the UI infers the editor type from that key.
Unlike broadcasts, a journey does not need to be a draft in order to edit message content. A live or paused journey is editable. Archived and locked journeys are rejected with 409 Conflict.
You cannot add a locale value to the default content and you cannot clear the locale on a localized content record. Duplicate locale values are rejected with 409 Conflict.
Authorizations
Accepts either a raw API key or Bearer <key>.
Headers
Optional dated API revision for the request. Must use YYYY-MM-DD format.
^\d{4}-\d{2}-\d{2}$"2026-03-01"
Path Parameters
Journey ID.
Message ID.
Content ID.
Body
New locale for a localized content. The default content's locale cannot be changed, and a locale already used on this message is rejected.
255Subject line. Omit to leave it unchanged.
Preheader text. Omit to leave it unchanged.
Channel content body — exactly one of mjml, html, text, or payload.

