Docs
How relay works: security, encryption, deliverability, reputation, privacy, reliability, sending, receiving, domains, webhooks, and message statuses.
Where relay runs, what relays stores and for how long, and what never happens to your data
How relay gets your messages into the inbox, and what every SMTP reply means
The built-in nameserver, managed sender domains, and verifying delegated domains
How relay encrypts messages in transit and protects signers key material at rest
The complete state machines for outgoing and incoming messages, with every transition
How the relay MX server accepts inbound mail and hands it to your webhooks
Queued delivery, transmission records, and retry schedules
How relay builds per-domain reputation and turns mailbox-provider reports into action
How relay protects your account, credentials, signing keys, and webhook deliveries
The relay SMTP interface, every acceptance rule, and the delivery pipeline
Standard Webhooks deliveries with Ed25519 signatures, verification code, and the retry schedule