X Activity API renames event types to dot format from March 18, 2026
What changed
On March 13, 2026 X announced that X Activity API event types move from PascalCase names (for example ProfileBioUpdate) to a dot-separated lowercase format (for example profile.update.bio), effective March 18, 2026. The PascalCase names are deprecated, and X tells developers to update any filtering, switch statements or deserialization logic that relies on the old values.
What it means
Code that matches X Activity API events by their old PascalCase names, such as ProfileBioUpdate, stops recognising events once they arrive under the new dot-format names.
Who is affected
Developers who subscribe to or parse X Activity API events.
What to do by 18 Mar 2026
Switch filters, switch statements and deserializers to the dot-format names such as profile.update.bio, and use those names when creating subscriptions.
What this means for you
Apps that get live alerts from X sort them by a name, like a label on a box. X changed how those labels are written. An app still looking for the old labels can miss alerts, for example that an account changed its profile. This is a job for app makers. If an app stopped noticing X changes after mid-March 2026, this may be why.
The details
- Announced: March 13, 2026. Effective: March 18, 2026.
- Old format (deprecated): PascalCase, as launched in the open beta:
ProfileBioUpdate,ProfilePictureUpdate,ProfileBannerUpdate,ProfileGeoUpdate,ProfileUrlUpdate. - New format: dot-separated lowercase. The changelog's example maps
ProfileBioUpdatetoprofile.update.bio. - Current profile names in the docs:
profile.update.bio,profile.update.profile_picture,profile.update.banner_picture,profile.update.screenname,profile.update.handle,profile.update.geo,profile.update.url,profile.update.verified_badgeandprofile.update.affiliate_badge. Other groups use the same pattern, such aspost.create,follow.followanddm.received. - What to update: "any filtering, switch statements, or deserialization logic that relies on the old values", in the changelog's words.
What to do next
- Business owners: Nothing.
- Marketers and agencies: Nothing, unless a tool stopped reacting to X profile or account changes after March 18, 2026: report it to the vendor.
- Developers: Replace every PascalCase event name with its dot-format name in subscriptions and handlers, using the names in the X Activity API introduction.
Primary sources
Get an email when a new API change is added
Follow new entries with the RSS feed. Each platform also has its own feed, for example X or Meta.