Content Triggers
| Trigger | Risk Level | Notes |
|---|---|---|
| ALL CAPS in subject | High | Instant spam signal |
| Exclamation marks!!! | Medium | One is fine, multiple = spam |
| "Free", "Discount", "Offer" | Medium | Contextual, but risky |
| "Urgent", "Act now" | High | Classic spam language |
| Dollar signs ($$$) | High | Avoid in subject lines |
| Phone numbers | Medium | Can look salesy |
| "Click here" | High | Use descriptive link text |
Technical Triggers
| Trigger | Risk Level | Notes |
|---|---|---|
| Tracking pixels | High | Invisible images = tracking |
| Shortened URLs | High | bit.ly, tinyurl = suspicious |
| Multiple links | Medium | Stick to one or none |
| Large attachments | High | Security systems block |
| Embedded images | Medium | Load from external server |
| HTML-heavy emails | Medium | Plain text is safer |
Sending Pattern Triggers
| Trigger | Risk Level | Notes |
|---|---|---|
| High volume from new domain | Critical | Classic spam pattern |
| Same email to many recipients | High | Personalize each |
| Sending at odd hours | Medium | Bots send 24/7 |
| Burst sending | High | Spread over time |
| No warmup | Critical | New domain + volume = spam |
Reputation Triggers
| Trigger | Risk Level | Notes |
|---|---|---|
| No SPF record | High | Basic authentication missing |
| No DKIM | High | Can't verify sender |
| No DMARC | Medium | No policy for failures |
| High bounce rate | High | Bad data = spammer signal |
| Spam complaints | Critical | Recipients marking as spam |
| Blacklisted domain/IP | Critical | Check regularly |
Safe Practices Checklist
Before every campaign, verify:
- [ ] Plain text format (minimal HTML)
- [ ] No tracking pixels
- [ ] One link maximum (your website)
- [ ] No attachments
- [ ] Personalized content
- [ ] Subject line is normal (no ALL CAPS, no $$$)
- [ ] SPF, DKIM, DMARC configured
- [ ] Bounce rate under 3%
- [ ] Domain not blacklisted
- [ ] Warmup complete (30 days)
Key Takeaway
Spam filters look for patterns. Avoid anything that looks automated, salesy, or technically suspicious. When in doubt, ask: "Would I send this exact email to a colleague?"