Domains & deliverability
Deliverability guide
What it takes to land in the inbox as a bulk sender — authentication, complaint rate, and list hygiene, all riding on your own domain's reputation.
Because Deckle sends from a domain you own and verify (Model A), your deliverability is yours to protect — one noisy sender can never poison a shared pool. The flip side is that the fundamentals are on you. Here’s the short list that keeps you in the inbox.
Bulk sender essentials#
Gmail and Yahoo enforce a baseline for anyone sending at volume. Deckle handles some of this for you and gives you the tools for the rest. Cover all of it:
- SPF, DKIM, and DMARC — authenticate every message. Publish all three when you verify your domain. See Domain authentication.
- One-click unsubscribe — every marketing send includes
List-Unsubscribeheaders and a visible link, as the bulk-sender rules require. - Complaint rate under 0.3% — keep spam complaints well below the threshold mailbox providers enforce.
- Enforced suppression — Deckle never sends to a suppressed address, and hard bounces and complaints are added automatically.
- Clean template markup — use the gallery templates or keep your HTML simple and inline-styled; messy markup trips spam filters.
- A plain-text alternative on every HTML email — Deckle’s template renderer produces one automatically alongside the HTML.
- Valid TLS and PTR — encrypted transport and reverse DNS are handled for you by AWS SES.
Watch your complaint rate#
Your complaint rate is the share of delivered messages that recipients mark as spam. It is the single metric most likely to get your sending throttled, so treat the 0.3% ceiling as a hard line, not a target.
Keep complaints under 0.3%
Mailbox providers start penalizing senders that cross a0.3% complaint rate. The dashboard warns you as you approach the threshold — if you see that warning, pause and review who you're emailing before you send more.List hygiene#
Most deliverability problems trace back to who you send to, not what you send. A smaller, engaged list beats a large, stale one every time. Make these habits:
- Send to engaged contacts. Favor people who have opened or clicked recently. Build a live segment for engagement and target it rather than blasting your whole list.
- Honor unsubscribes. Unsubscribing suppresses the contact automatically — never re-import or re-add someone who opted out.
- Remove hard bounces. Hard bounces are auto-suppressed, so repeatedly sending to dead addresses can’t happen — but clean them out of your source lists too so your metrics stay honest.
The suppression list is your safety net for all of this. It records the reason for every entry — hard_bounce, complaint, unsubscribe, or manual — and Deckle rejects any send to a suppressed address with a 422.