The vocabulary,
decoded.

Symmetric block cipher with a 256-bit key, used for encryption-at-rest. Every VoltMail database, backup, and object-store payload is encrypted with AES-256 and per-customer key envelopes.

A DNS TXT record that authorises an SVG logo to render next to your sender name in supported inboxes. Requires a DMARC policy of quarantine or reject and (for Gmail/Apple) a Verified Mark Certificate.

Percentage of sends that the receiving MTA refused. Hard bounces are permanent (invalid address); soft bounces are temporary (full mailbox, server down). Above ~3% sustained, ISPs throttle or quarantine your domain.

Cryptographic signature added to email headers. Receivers fetch the public key from DNS and verify that the message body has not been altered. VoltMail rotates DKIM with two selectors so rotation is zero-downtime.

Policy record sitting on top of SPF + DKIM. Tells receivers what to do when both fail (none / quarantine / reject) and where to send aggregate or forensic reports.

The first SMTP command issued by a sending server, identifying itself to the receiver. Reverse-DNS on the EHLO host should resolve back to the source IP — or many ISPs reject the connection outright.

A program (run by AOL, Yahoo, Comcast, others) that forwards spam complaints back to the sending domain. We ingest these continuously and add complainants to your suppression list within seconds.

Contract between a covered entity (a hospital, insurer, etc.) and a vendor that handles Protected Health Information. VoltMail offers a BAA on Pro Max with HIPAA-conformant infrastructure.

Symmetric signature scheme. Every VoltMail webhook delivery carries an X-VoltMail-Signature header containing an HMAC-SHA256 over (timestamp + body). Verify it before trusting the payload.

A client-generated identifier passed in the Idempotency-Key request header. We cache the (key, response) pair for 24 hours; identical retries return the same response without performing the work twice.

The process of slowly building reputation on a brand-new dedicated IP by sending small, gradually-increasing volume. Skipping the warm reliably parks new mail in spam for weeks. Our auto-warm doubles every 36 hours.

A header (and one-click HTTPS endpoint) Gmail and Yahoo require on bulk email. Recipients click "unsubscribe" in the inbox UI; we honor it within 200ms server-side.

Software that accepts mail over SMTP and routes it. Postal, Postfix, and Exim are MTAs. VoltMail runs a Postal cluster in production with custom queue + retry logic.

A DNS record listing the mail servers responsible for receiving mail at a domain. Outbound senders look up the MX, then connect to the highest-priority host.

A per-IP and per-domain score every major receiver maintains. Sources include bounce rate, complaint rate, spam-trap hits, and engagement signals. Below threshold, you go to spam.

An email address used to catch senders with poor list hygiene. Pristine traps were never opted-in; recycled traps were once valid but now expire. A single hit can damage your reputation for weeks.

A TXT record that lists the IPs authorised to send mail "from" your domain. Receivers reject mail whose source IP is not in the list.

A per-account record of email addresses that should never receive mail again — typically populated by hard bounces, complaints, and unsubs. We maintain a global list across all of your sending domains.

Transport-layer encryption for SMTP and HTTPS. Every VoltMail connection (SMTP, dashboard, API) is TLS 1.3 with HSTS preloaded.

A certificate proving you own the trademark on your BIMI logo. Issued by Entrust or DigiCert; required by Gmail and Apple Mail to render the logo.

The ability to re-emit past webhook deliveries against a live or new endpoint. Useful for backfilling state after an outage. Pro+ stores 30 days of replayable events; Pro Max stores 90.