Deliverability starts before the first campaign. Zilch Mail can sign messages with DKIM, schedule warm-up activity, and show domain health signals, but those tools work best when your DNS records, sender identity, content, and recipient consent are already in order.
What each authentication record does
| Record | Purpose | Practical check |
|---|---|---|
| SPF | Lists servers and services allowed to send for a domain | The provider sending your message is included and there is only one effective SPF record |
| DKIM | Adds a cryptographic signature that receiving servers can verify | The selector is published and the signature passes on a real test message |
| DMARC | Tells receivers how to handle failed alignment and where to send reports | The policy matches your rollout stage and the From domain aligns with SPF or DKIM |
Configure the domain in a safe order
- 1Confirm ownership of the sending domain and identify every legitimate sender.
- 2Publish or update SPF for the SMTP and provider services you actually use.
- 3Generate or configure DKIM and publish the selector record at your DNS host.
- 4Start DMARC with a monitoring-oriented policy while you inspect reports and alignment.
- 5Send test messages to multiple providers and check authentication results in the received headers.
- 6Increase enforcement only after legitimate traffic consistently passes.
Warm up the sender gradually
Warm-up is a pattern of consistent, expected sending—not a shortcut around reputation. Use the scheduler to increase volume gradually, keep early content useful and relevant, and avoid changing domains, From identities, and sending patterns at the same time.
Never warm up with recipients who did not expect your mail
A warm-up schedule cannot turn unwanted messages into wanted messages. Use recipients who have a legitimate relationship with you and follow every provider’s acceptable-use rules.
Use the deliverability checklist before scaling
- SPF, DKIM, and DMARC checks pass for the actual From domain.
- The Reply-To address is monitored and the unsubscribe path works.
- The recipient segment is current, permissioned, and suppressed where required.
- The content renders correctly in HTML and plain text.
- Links resolve through a domain you control and do not look misleading.
- Recent hard bounces and complaints are reviewed before increasing volume.
Use seed testing as a signal
Seed inbox placement testing can reveal authentication, formatting, and reputation signals across providers. Treat it as directional evidence alongside real delivery, bounce, complaint, and reply data—not as a guarantee that every recipient will see the same placement.