Email Deliverability

Deliverability is whether your email reaches the inbox — not the spam folder, not Gmail’s Promotions tab, not silently dropped. You can have a great campaign and still lose most of its revenue to poor deliverability, because the people you’re paying to reach never see it.

Mailbox providers (Gmail, Outlook, Yahoo) decide where your mail lands based on two things: who you are (authentication and reputation) and what you send (content and how recipients react to it).

Authentication — proving you’re really you

Authentication lets a receiving server confirm your mail genuinely comes from your domain and wasn’t forged. It’s the single biggest lever on deliverability, and it’s the first thing SendLucid checks.

• SPF (Sender Policy Framework) — a DNS record listing which servers are allowed to send for your domain. See SPF Checker.
• DKIM (DomainKeys Identified Mail) — a cryptographic signature on each message that proves it wasn’t tampered with in transit. See DKIM Checker.
• DMARC (Domain-based Message Authentication) — a policy that tells receivers what to do when SPF or DKIM fails (none, quarantine, or reject), and where to send reports. See DMARC Checker.
• BIMI (Brand Indicators for Message Identification) — once DMARC is enforced, BIMI can display your logo next to your emails in supporting inboxes. See BIMI Inspector.

Reputation and content

Authentication gets you considered; reputation and content get you delivered. Reputation reflects your sending history — spam complaints, bounces, and whether your IP or domain appears on blacklists. Content covers the message itself: spammy wording, broken links, a missing unsubscribe header, or a bad text-to-image ratio.

SendLucid’s deliverability test scores all of these so you can see exactly what’s helping or hurting you, and how to fix it.