---
title: "Blog"
description: "Guides from the Nextmail team on deliverability, domains, sending and the inbox, with the sources behind every claim."
url: "https://nextmail.sh/blog"
---

Blog

# Notes on email, from the people building it.

Guides on deliverability, domains and the inbox, written by the Nextmail team. Every claim links to its source.

Oct 31, 2026 8 min read

## Best AI email clients for 2026: 8 apps compared

Eight AI email clients compared on what their AI does, the mail they work with and the price in 2026, from Nextmail and Superhuman to Gmail and Outlook.

Benjamin AI

Oct 31, 2026 6 min read

## How to build your own email client on Nextmail

What you need to build your own email client on Nextmail: OAuth sign-in for your users, typed SDKs in seven languages, live events, webhooks and raw messages.

Arta Developers

Oct 31, 2026 5 min read

## Email as a mailbox: why AI agents need a real inbox

Most email APIs only send. What a real mailbox adds for apps and AI agents, the four ways to get one in 2026, and how much code each leaves you.

Benjamin AI

Oct 31, 2026 9 min read

## Resend pricing in 2026: what it costs, how to pay less

What Resend costs at 50,000 to 1,000,000 emails a month, with every plan, overage rate and add-on, and what the same mail costs on Nextmail.

Benjamin Comparisons

Oct 31, 2026 5 min read

## SPF, DKIM and DMARC explained: how inboxes trust mail

What SPF, DKIM and DMARC each check, why alignment decides whether DMARC passes, and a safe order for moving a domain from p=none to p=reject.

Benjamin Deliverability

Oct 31, 2026 9 min read

## What is an email client? How email clients work

An email client is the app you read and send mail in, apart from the service that holds your mailbox. How clients find servers, sync, send and guard privacy.

Benjamin Email clients

Oct 31, 2026 10 min read

## What is BIMI? Inbox logos and how to get a certificate

BIMI is a DNS record that puts your logo beside mail that passes DMARC. How the record, the BIMI logo and VMC or CMC certificates work, inbox by inbox.

Arta Deliverability

Oct 31, 2026 9 min read

## What is DKIM? How DKIM signatures and records work

DKIM is a signature on every email that proves which domain vouches for it and that nothing changed on the way. How it works, tag by tag, and which keys to use.

Benjamin Deliverability

Oct 31, 2026 9 min read

## What is DMARC? Policy, reports and getting to p=reject

DMARC is a DNS record that checks SPF and DKIM against your visible From domain, tells inboxes what to do with mail that fails and reports who sends as you.

Arta Deliverability

Oct 31, 2026 10 min read

## What is IMAP? How IMAP works: ports, sync and security

IMAP is how mail apps read and organise mail that stays on the server, in sync on every device. How it works, which port to use and how it compares with POP3.

Arta Protocols

Oct 31, 2026 6 min read

## What is JMAP? The JSON email protocol, explained

JMAP is the IETF standard for email, contacts and calendars over JSON and HTTPS. How it works, how it differs from IMAP, and who supports it in 2026.

Arta Developers

Oct 31, 2026 10 min read

## What is SMTP? How it works, from ports to reply codes

SMTP is the protocol that carries email from your app to your provider and between mail servers. How it works, which port to use and what each reply means.

Benjamin Protocols

Oct 31, 2026 9 min read

## What is SPF? How SPF records work and where they break

SPF is the DNS record that lists the servers allowed to send mail for your domain. How receivers check it, what each part means and what quietly breaks it.

Arta Deliverability

Try it yourself

## Your email, on your own domain.

Nextmail puts your domains, sending and inbox in one place, with the full API on every plan, the free one included.

[Open mail](https://nextmail.sh/mail/inbox) [Get Started](https://nextmail.sh/signup.md)