Password Reset Email Deliverability for Custom Domain Provider (and Bounce Evidence Limits)

Short answer: for marketplace password recovery, choose the delivery setup that can prove what happened to every message, then keep the suppression decision in your own system. Inbox placement matters, but an evidence trail is the decision axis. A custom sending domain with aligned DKIM and SPF, bounce events, and exportable history gives an auditor something better than a green dashboard. The decision note: which delivery shape leaves evidence? Delivery shape Evidence you can normally retain Best fit Trade-off Managed transactional service Webhooks, message ids, DNS guidance Teams that need mailbox feedback quickly Retention and event detail vary by contract Cloud notification primitive Basic accepted or failed status Small systems with an existing mail pipeline Bounce reason and suppression semantics may be thin Self-hosted MTA Full local logs and routing policy Data-residency teams with on-call capacity Reputation, feedback loops, and maintenance become yours My default is the first shape, with a local ledger beside it. The transport can change; the account-recovery policy should not. That split also makes a provider review concrete: ask for a sample event export, its retention period, and the fields that connect a bounce to a reset request. The catch is operational capacity. A self-hosted stack is not suitable for a marketplace that cannot staff reputation incidents, while a managed service is a poor fit when its export cannot satisfy your retention or residency rules. Keep the cloud primitive for low-volume internal tools, not as an automatic answer for customer recovery. What must a password reset email evidence trail capture? Begin with the reset request. Store a hash of a random, single-use token, its expiry, the account identifier, and the request time. OWASP recommends a consistent response for existing and non-existing accounts, rate limiting, and invalidation after use; those controls prevent delivery telemetry from becoming an account-enumeration signal