MXToolbox

Checks SPF, DKIM, DMARC, MX and blacklists for a domain.

What it is for

Verifying email authentication before an outreach or newsletter send; the SuperTool covers most checks free.

deliverability · DNS · SPF · DKIM · DMARC

Google email sender guidelines◆ — The rules Gmail applies to bulk senders — authentication, unsubscribe, spam rate. free
beehiiv — Newsletter platform built around growth — referrals, recommendations, ad network. free tier
Buttondown — A minimal, developer-friendly newsletter tool with Markdown and an API. free tier
Instantly — Cold-email sending with mailbox warm-up and rotation. paid
Kit (formerly ConvertKit) — Creator email with automations, landing pages and commerce. free tier
NeverBounce — Email list verification to keep bounces under control. paid
Substack — Newsletter publishing with a built-in discovery network and paid tiers. free tier

Suggest a correction — a changed price, a moved page, a better tool for the task.