Email deliverability for self-hosted senders

Explanation

For:: Publishers and marketers, Workspace admins

Email deliverability is whether your mail reaches the inbox instead of the spam folder or a bounce. Mailbox providers such as Gmail, Yahoo and Outlook.com decide that for every message, from the signals below. When you self-host, you choose the sending providers and own the DNS, so these signals are yours to manage; ReputeCast checks them before, while and after each send.

What decides inbox placement

Signal	What mailbox providers look at	Where to work on it
Authentication	SPF, DKIM and DMARC, aligned with the domain in the From address	Set up SPF, DKIM and DMARC
Reputation	The history of your sending domains and IPs, blocklist listings, bounce and complaint rates	Monitor domain and provider health, warm-up
Engagement	How recipients react: opening, replying, deleting unread, reporting spam	Keep your list healthy
Content	Size, links, images, a plain-text part, a subject that doesn’t look like spam	Fix content warnings before sending
List quality	Addresses that bounce, spam traps, role addresses, contacts who never signed up	The suppression list, verify addresses
Compliance	Consent, a working unsubscribe, a postal address, the bulk sender rules	Gmail, Yahoo and Microsoft bulk sender requirements

How ReputeCast acts before, while and after sending

Send Readiness checks a campaign before it starts, routing hands each recipient to a sending provider, delivery events come back from the sending providers, and thresholds decide whether the send keeps going or pauses.

Before you send. Domain records are checked live while you publish them and every 30 minutes after that. Send Readiness checks each campaign in up to ten groups: sender reputation, authentication, content, languages, accessibility, conditional content, links, compliance, audience quality and routing. Its verdict is Ready, Ready with warnings or Blocked, and a Block keeps the send from starting. It runs when you open Review & send, again 15 minutes before a scheduled send, and when the send starts. A placement test shows where real copies land in seed mailboxes.
While you send. Guarded sending watches bounce, complaint and deferral rates per mailbox provider and per sending provider every 2 seconds, and auto-pauses only the part that crossed a threshold. When a sending provider fails, the route’s failover policy decides whether its share moves to a healthy one or waits for you.
After you send. Delivery events from every sending provider are normalized, and bounces and complaints go to one suppression list that applies to every sending provider. Campaign reports separate human from machine opens, and Deliverability health keeps watching your domains, IPs, sending provider accounts, blocklists, DMARC reports and incidents.

Defaults and limits

These Send Readiness timings and thresholds apply to every campaign:

Setting	Default	How to change
Checks run again before a scheduled send	15 minutes before the send time	Fixed
A held send is checked again	Every 15 minutes	Fixed
HostRepute request timeout before "Continue with provider data only" is offered	30 s per request, 3 attempts	Fixed
Email sends that need the recipient count typed to confirm	1,000 recipients or more	Fixed
Best time per recipient	Each contact's most frequent open hour, up to 24 hours after the scheduled time; contacts without opens get the scheduled time	Review & send › Scheduling
Earliest time you can schedule a send	1 minute from now	Fixed
Warning for contacts with no open or click in 180 days	1% of the audience or 500 contacts	Fixed; the 180 days follow the sunset policy in Audience › List health
Window for recently bounced contacts	30 days	Fixed
Warning for risky addresses found by address verification	2% of the audience	Fixed
Warning for At risk and Sunset contacts not verified in 90 days	10% of the audience	Fixed

When to change them

The Send Readiness limits are fixed. What you decide is how to answer each result: fix a Block, and fix or confirm each warning before you send. The thresholds that end a send early are yours to tune: auto-pause rates per workspace and per campaign (Monitor a send and auto-pause), and each sending provider’s bounce and complaint limits (Provider health and outages). Lower them when a mailbox provider starts deferring or filtering your mail; raising them only lets more damage happen before the pause.

Deliverability checklist

Set up once

Publish SPF, DKIM and DMARC for every sending domain: Set up SPF, DKIM and DMARC.
Collect DMARC reports and move to an enforced policy: Read DMARC aggregate reports.
Check the rules of the large mailbox providers: Gmail, Yahoo and Microsoft bulk sender requirements.
Make sure one-click unsubscribe works, which needs an HTTPS public URL: One-click unsubscribe (RFC 8058).
Collect consent with evidence and keep a postal address in the footer: Consent and anti-spam law basics.
With Amazon SES, leave the sandbox before the first campaign: Move Amazon SES out of the sandbox.
Warm up a new sending provider or IP before full volume: Warm up a new provider or IP.
Optional: show your logo with BIMI, and connect HostRepute for hourly blocklist checks, Postmaster Tools, SNDS and DMARC collection.

Before every send

Fix every Block and read every warning in Send Readiness.
For important sends, run a placement test first.

Keep watching

Open Deliverability health regularly and act on amber and red cards.
Get listings removed quickly: Check and fix blocklist listings.
Stay under the limits of each sending provider: Bounces, complaints and provider limits.
Stop mailing contacts who never engage: Keep your list healthy and The suppression list.

When mail bounces

Look up the code a mailbox provider returned: SMTP error codes.
Find which mailbox providers and sending providers it affects in campaign reports.