Every application sends from its own domain

Shared sender domains are how transactional mail platforms get into trouble. One customer’s bounce rate becomes everyone’s reputation problem, and a recipient sees a brand they do not recognise in the From line.

DevSewa Mail has no global default. A message must name a domain_key, and that key must be a sender lane — a domain registered in the mail engine with its own SMTP identity and DNS — assigned to exactly one application. If an application has no lane yet, sending fails loudly with mail_domain_not_configured rather than quietly borrowing somebody else’s domain.

• The console shows every lane on your account and which application owns it.
• A domain field that contains an @ is rejected before it is stored; the alias field carries the local part.
• Before SMTP is even attempted, the computed From address is checked against the lane’s authenticated identity, so misconfiguration surfaces as a clear sender_identity_mismatch instead of a provider rejection.

Behind the lane, DevSewa signs to the mail engine as one caller and names your tenant as the message origin, with idempotency keys namespaced per tenant. Two applications retrying the same event id can never cancel each other out.