We begin with the reason for the subdomain. A shop on its own platform, a client portal, a separate language site, a staging area for testing, a booking tool hosted by another provider or a regional microsite each need different handling. We ask what will live there, who will manage it, where it is hosted and whether it should appear in search results. For content you want found, we usually advise a folder on the main site, such as /blog/, because it keeps authority together; a subdomain suits a distinct application, a third-party service or a private area. We explain the trade-off honestly and let you choose. Next we take a safe snapshot of your current DNS: every A, AAAA, CNAME, MX, TXT and NS record, with notes on what each does. We find out who controls the DNS, whether at the registrar, the hosting company or a service such as Cloudflare, and confirm we have the right level of access without asking for your main account password; see domain DNS configuration. We agree the name, keeping it short, readable and consistent with your brand. We add the DNS record that suits the case: an A record to point to a server address, or a CNAME to point to a platform such as a store or booking tool, with the target given by the service. We set a sensible time-to-live so that changes spread quickly. On the hosting side, we create the subdomain in the control panel or server, set the document root, or add the domain to the external platform and verify ownership; see hosting resource optimization. We issue an SSL certificate for the subdomain, either individually or through a wildcard certificate when many subdomains are planned, and force HTTPS. For WordPress setups we configure the install or multisite correctly, and fix settings such as site address and cookies. We check email: the new record must not disturb MX, SPF, DKIM or DMARC records, and where the subdomain sends email we add the right authentication. We handle search aspects: whether to allow indexing, a robots rule for staging copies, canonical tags where content is shared and redirects from old addresses; see domain redirects. We test from outside: the address resolves, HTTPS shows no warning, the right site loads on desktop and mobile and nothing else on the domain changed. We wait for propagation and test again from a different network. We document what was added, where, why and how to remove it, and we set a reminder to renew certificates if they are not automatic; see domain renewal coordination. We cannot control third-party platforms that restrict custom subdomains, nor speed up internet-wide DNS updates, but a planned, recorded and tested subdomain keeps your main website and email safe.
