Sending & Deliverability
How you send email decides whether it reaches the inbox. This page covers the sending options and the deliverability basics that matter most.
Sending options
Section titled “Sending options”Configure sending under Settings then Sending.
| Option | Plan | Best for |
|---|---|---|
| PHP Mail | Free | Quick testing and very low volume |
| Custom SMTP | Free | Real sending through any SMTP server |
| Amazon SES | Pro | High volume at low cost |
| SendGrid | Pro | High volume with detailed provider analytics |
| Mailgun | Pro | Developer-friendly high-volume sending |
| Postmark | Pro | Fast, reputation-focused delivery |
| Brevo | Pro | All-in-one sending |
PHP Mail uses whatever your server provides and is the least reliable for real campaigns. For anything beyond testing, use Custom SMTP or, with Pro, a dedicated email service provider.
How PrimoCRM paces sending
Section titled “How PrimoCRM paces sending”Campaigns and sequences are delivered by a background worker in throttled batches that respect your mailer’s limits. This protects your server, stays within your provider’s rate limits, and avoids the timeouts you get from trying to send a large list in one request. You do not need to configure batching; it adapts to your chosen sending method.
Deliverability basics
Section titled “Deliverability basics”Getting into the inbox is mostly about authentication and list hygiene.
Authenticate your domain
Section titled “Authenticate your domain”Set up these DNS records for your sending domain. Your SMTP provider or ESP gives you the exact values.
- SPF: authorizes your provider to send for your domain.
- DKIM: cryptographically signs your mail so receivers can verify it.
- DMARC: tells receivers what to do with mail that fails SPF or DKIM.
Sending from a domain you control with SPF and DKIM in place is the single biggest factor in reaching the inbox.
Use a real from-address
Section titled “Use a real from-address”Send from an address at your own authenticated domain, for example
hello@yourbrand.com. Avoid free-mailbox from-addresses such as a gmail.com
address, which fail DMARC alignment and are commonly filtered.
Keep your list clean
Section titled “Keep your list clean”- Only email Subscribed contacts. PrimoCRM already excludes unsubscribed, bounced, and complained contacts automatically.
- Remove or stop mailing addresses that repeatedly bounce.
- Watch your reports for rising bounce or complaint rates and act early.
Warm up and pace new domains
Section titled “Warm up and pace new domains”If you are sending from a new domain or IP, start with smaller, engaged segments and grow volume over a couple of weeks. A sudden large send from a cold domain is a common reason mail lands in spam.
Write mailable content
Section titled “Write mailable content”- Keep a genuine unsubscribe link in every email. It is required and it reduces spam complaints.
- Avoid spam-trigger phrasing, all-caps subjects, and link shorteners.
- Send relevant content to people who asked for it. Engagement is a ranking signal for inbox placement.