Every Signal sending domain has a region.
That region controls the Signal sending path used for the domain.
Supported region codes
Default behavior
When a project does not have multi-region domain capability, a new domain uses the project’s region.
The add-domain interface shows that value as locked.
When multi-region domain capability is enabled, the add-domain interface exposes the supported region choices.
Use the options shown in the dashboard as the current entitlement; do not infer availability from this list alone.
Immutability
A registered domain’s region cannot be changed.
The domain response exposes the selected region, and the dashboard treats it as a fixed property.
To change region, register a replacement domain and migrate senders:
- Add the replacement in the target region.
- Publish the returned DNS records.
- Wait for required checks to verify.
- Configure the project’s tracking behavior as required.
- Move one controlled caller.
- Compare send, delivery, and webhook evidence.
- Move remaining callers.
- Delete the old registration only after it is unused.
What region does not prove
Region selection does not prove provider handoff, recipient-server acceptance, inbox placement, or engagement.
Use message status and event evidence for those questions.
Do not delete the original domain as the first migration step.
Deletion stops new sending from it immediately.
