Projects, regions, and data boundaries

A project is Signal’s customer isolation boundary. Its domains, API keys, contacts, custom properties, segments, topics, suppressions, messages, webhooks, usage, and metrics belong to that project.

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What project-bound means

• An API key authenticates to one project.
• A verified domain in one project does not make that domain available to another project.
• Contact and suppression state does not cross project boundaries.
• Message IDs, webhook endpoints, usage, and metrics are resolved in the authenticated project.
• A topic or segment audience ID must belong to the same project as the sending key.

Use separate projects when production and non-production data must not mix. This gives each environment its own credentials, sender configuration, audiences, suppressions, events, and usage record.

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Project regions

You select a project region when creating the project. Signal exposes the region as read-only afterward; changing it requires a separate project and a controlled migration. Availability can depend on the active plan, so use the choices shown by the creation dialog as the live entitlement.

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Domain regions

Every sending domain also has a region. Without multi-region domain capability, a new domain uses the project region and the dashboard locks that choice. With the capability enabled, the add-domain dialog exposes the supported regions. A domain’s region cannot be changed after registration. To move a sender to another region:

1. Register the replacement domain in the target region.
2. Publish and verify its DNS records.
3. Reconfigure tracking and BIMI when used.
4. Move a controlled caller or traffic slice.
5. Confirm message and webhook behavior.
6. Move the remaining From addresses.
7. Remove the old domain only after no caller uses it.