--- search: tags: - Domains - POST seo: description: >- Registers a sending domain and returns the DNS records to publish: SPF, DKIM, DMARC, a return… Reference for the POST /domains endpoint in the AI Inbx API API. sidebar: label: Create a domain badge: POST title: Create a domain type: openapi-operation --- Registers a sending domain and returns the DNS records to publish: SPF, DKIM, DMARC, a return path, and an MX record for receiving. `region` selects the regional mail infrastructure for this domain and cannot be changed afterwards. A wildcard — `*.acme.dev` — is verified once and covers every subdomain: the MX record goes at `*.acme.dev`, the rest at `acme.dev`, and the apex keeps whatever mail setup it has. A name one label under a wildcard of yours — `hi.acme.dev` under `*.acme.dev` — is created as a subdomain of it: no records, verified as soon as the wildcard is, in whatever `space_id` you give it. That is how a platform hands each customer an address of their own without touching DNS again. A domain name can be connected in multiple workspaces, but sending is enabled for the workspace whose DKIM key is published. To move sending, add the domain in the destination workspace and publish its DNS records. The next verification check updates sending readiness; existing mail remains in its original workspace. Duplicate apex or wildcard identities within one workspace fail with `domain_taken`. Every workspace already has one domain it did not add: `.aiinbx.app`, listed with `provided: true`. It is verified through our zone, has no records and cannot be deleted; a name under `aiinbx.app` cannot be added by hand and fails with `reserved_domain`.