Check a domain name or diagnose its DNS

Resolve the owner's domain question in their current stack. A domain purchase is optional: a published platform URL already works, and a domain the owner already owns can be reused. An existing-domain problem should lead to diagnosis, not a new-name sales flow.

Availability and renewal costs

For a new name, use the read-only JSON endpoint:

GET https://www.adddomain.net/api/check?name=example.com

For a bare label, GET https://www.adddomain.net/api/check?name=example&tlds=com,net checks those endings; a full domain checks only that exact name. Use at most six endings per call; registries rate-limit, so do not loop over hundreds of names. If an incoming link has a valid src label, preserve it on check and buy-link requests.

Interpret each result separately:

• available: no registry registration record was found. Premium, reserved or newly registered names can still be refused at checkout; this is not a reservation.
• registered: already registered. Do not offer it as a new registration or turn this result into proof that the owner controls it.
• unknown: no reliable registry answer. Say unknown and let the owner confirm at a registrar. DNS silence is not availability.