SPF, DKIM, and DMARC Explained Simply (with Infographics)

Pelle Penttinen — Tue, 19 Aug 2025 16:27:58 +0000

Email spoofing and phishing are still some of the most common ways attackers trick people. The good news is that there are three simple standards that can protect your domain and make sure your messages get delivered where they belong. If you’ve ever been confused by SPF, DKIM, and DMARC, this post will break them down in plain English.

SPF (Sender Policy Framework): Think of it as a guest list. It tells receiving servers which mail servers are allowed to send on behalf of your domain.
DKIM (DomainKeys Identified Mail): Works like a tamper-proof seal. It adds a digital signature to your emails so recipients know they haven’t been altered in transit.
DMARC (Domain-based Message Authentication, Reporting & Conformance): This is the referee. It checks whether SPF and DKIM align with your domain, then applies your policy (monitor, quarantine, or reject).

Why it matters

Stops spoofing and phishing using your domain
Improves deliverability (your legit emails land in the inbox)
Gives you visibility via DMARC reports

I’ve also created simple infographics to show exactly how these checks work step-by-step.

If you want the full breakdown (with all the graphics), check out the original article here:

👉 SPF, DKIM, and DMARC Explained Simply

Setting these up properly can make a huge difference in protecting your domain and your customers’ inboxes.

DEV Community: Pelle Penttinen

SPF, DKIM, and DMARC Explained Simply (with Infographics)

Why it matters