> Plain-English definitions of email terms for developers: SPF, DKIM, DMARC, return path, bounces, complaints, sender reputation, BIMI, MTA-STS, webhooks and more.

Source: https://vaartix.com/glossary

# Email glossary

Plain-English definitions for developers who send email

The words you meet when you set up a sending domain, read a bounce or debug a spam-folder problem: what each one means, and what it means for you.

-   [**BIMI**](https://vaartix.com/glossary/bimi)A DNS record (`default._bimi.yourdomain`) that points to your logo, so supporting mailbox providers can show it next to your emails.
-   [**Bounce (hard and soft)**](https://vaartix.com/glossary/bounce)A message from the receiving server saying it couldn't deliver an email. A hard bounce is permanent (the address doesn't exist); a soft bounce is temporary (a full mailbox, or the server is busy).
-   [**Click tracking**](https://vaartix.com/glossary/click-tracking)Counting clicks by sending each link through a redirect that records the click, then forwards to the real page.
-   [**Complaint**](https://vaartix.com/glossary/complaint)A report that a recipient marked your email as spam, passed back to the sender by mailbox providers that offer a feedback loop.
-   [**Dedicated IP**](https://vaartix.com/glossary/dedicated-ip)An IP address that sends only one sender's email, instead of an address shared by many senders.
-   [**Deliverability**](https://vaartix.com/glossary/deliverability)Whether your email reaches the inbox, rather than the spam folder or nowhere at all. It depends on authentication, your sending reputation and the content.
-   [**DKIM**](https://vaartix.com/glossary/dkim)A cryptographic signature added to every email. The receiving server checks it with a public key published in your DNS, which proves the email came from your domain and wasn't changed on the way.
-   [**DMARC**](https://vaartix.com/glossary/dmarc)A DNS TXT record at `_dmarc.yourdomain` that tells receiving servers what to do with email that fails SPF and DKIM alignment (nothing, quarantine it or reject it) and where to send reports.
-   [**Idempotency key**](https://vaartix.com/glossary/idempotency-key)A unique value you send with a request so that retrying it doesn't repeat the action.
-   [**IP warm-up**](https://vaartix.com/glossary/ip-warm-up)Sending a small amount of email from a new IP address or domain at first, and increasing it gradually, so mailbox providers learn to trust it.
-   [**MTA-STS**](https://vaartix.com/glossary/mta-sts)A policy, published in DNS and on an HTTPS URL, that tells sending servers to deliver email to your domain only over an encrypted (TLS) connection with a valid certificate.
-   [**MX record**](https://vaartix.com/glossary/mx-record)A DNS record that says which server receives email for a domain or subdomain.
-   [**Open tracking**](https://vaartix.com/glossary/open-tracking)Counting opens with a tiny invisible image in the email: when it loads, the email was (probably) opened.
-   [**Return path**](https://vaartix.com/glossary/return-path)The hidden address that bounces go back to, separate from the From address people see. SPF is checked against its domain.
-   [**Sender reputation**](https://vaartix.com/glossary/sender-reputation)How much mailbox providers trust mail from your domain and from the IP addresses it's sent from, based on its history: bounces, complaints, spam traps and how recipients engage.
-   [**SPF**](https://vaartix.com/glossary/spf)A DNS TXT record that lists the servers allowed to send email for a domain. Receiving servers check it against the domain in the hidden return path, not the From address you see.
-   [**Suppression list**](https://vaartix.com/glossary/suppression-list)A list of addresses an email service won't send to, usually because they bounced or complained.
-   [**TLS-RPT**](https://vaartix.com/glossary/tls-rpt)A DNS TXT record (`_smtp._tls.yourdomain`) that asks sending servers to report problems they had making encrypted connections to your mail servers.
-   [**Transactional vs marketing email**](https://vaartix.com/glossary/transactional-vs-marketing-email)Transactional email is sent to one person because of something they did: a login code, a receipt, a password reset. Marketing email is sent to many people to promote something: newsletters, offers, campaigns.
-   [**Webhook**](https://vaartix.com/glossary/webhook)An HTTP request a service sends to a URL you choose when something happens, so you don't have to keep asking.

**Vaartix is a transactional email API built in India.** SPF, DKIM and a return path on your domain are set up for you, and every feature is free during the private beta.

[Request early access](https://vaartix.com/#early-access)