Email Warmup
Email Warmup automatically builds sender reputation for new mailboxes by sending and receiving engagement emails at a controlled pace. This ensures your outbound emails land in the inbox, not spam.
Why Warmup Matters
New email accounts have no reputation with inbox providers (Gmail, Outlook, Yahoo). Sending a high volume of cold emails from a new account triggers spam filters. Warmup solves this by gradually increasing send volume while generating positive engagement signals (opens, replies, moves from spam to inbox).
How Warmup Starts
For purchased domains and mailboxes, warmup starts automatically in the background. A background worker enrolls the mailbox in warmup as soon as it’s provisioned — no manual action required.
If you need to start warmup manually (or restart it after a pause), you can do so from the Purchase Domain & Mailboxes section.
Manual Start (Purchased Mailboxes)
Manual start is available only from the Purchase Domain & Mailboxes page — not from the standard Mailboxes page or the Domains page.
- Go to Settings → Purchase Domain/Mailboxes
- On the Domains tab, click the domain that owns the mailbox
- Switch to the Mailboxes tab for that domain
- Click the mailbox you want to warm up
- Open the Warmup tab
- Click Settings to configure warmup parameters, or Refresh to pull the latest stats
Warmup Settings
From the mailbox’s Warmup tab, click Settings to adjust:
| Setting | Description | Recommended |
|---|---|---|
| Daily limit | Maximum emails sent per day during warmup | Start at 5, ramp to 40+ |
| Ramp-up speed | How quickly daily volume increases | Gradual (2-3 weeks to full volume) |
| Reply rate | Target percentage of warmup emails that get replies | 30–40% |
Warmup Providers
graph8 supports two warmup providers:
| Provider | Best For |
|---|---|
| Instantly | Default provider, works with most mailboxes |
| SmartLead | Alternative provider, used with purchased domains |
Provider selection happens at the domain level when the domain is purchased.
Monitoring Warmup Progress
The Warmup tab on a mailbox shows real-time analytics.
Summary (Last 7 Days)
Four headline cards summarize recent activity:
| Metric | What It Shows |
|---|---|
| Warmup emails sent | Total warmup messages delivered in the last 7 days |
| Landed in inbox | Count of warmup emails that landed in the primary inbox |
| Saved from spam | Count of warmup emails that were marked “not spam” by the warmup network |
| Emails replied | Count of warmup emails that received a reply |
Daily Chart — Warmup Emails Sent, Spam & Replied
A daily stacked bar chart shows:
| Series | Meaning |
|---|---|
| Sent | Warmup emails delivered that day |
| Replied | Warmup emails that received a reply |
| Landed in Spam | Warmup emails that landed in spam — should trend toward zero |
| Saved from Spam | Warmup emails recovered from spam by the warmup network |
Click Refresh to pull the latest data from the warmup provider.
What a Healthy Warmup Looks Like
| Indicator | Healthy Range |
|---|---|
| Daily volume | Steadily increasing for the first 2–3 weeks, then steady |
| Reply rate | Above 25% |
| Inbox placement | Above 90% |
| Spam volume | Trending toward zero |
If spam volume stays high for several days, pause outbound sending and let warmup rebuild reputation.
Placement Testing
Placement testing measures where your emails actually land — primary inbox, promotions, spam, or quarantine — across Gmail, Outlook, Yahoo, and other major providers. This is the single most reliable deliverability signal; reputation scores lag, but placement tests reveal problems immediately.
When to Run a Test
| Scenario | Recommended Frequency |
|---|---|
| New domain warmup | Weekly during the first 4 weeks |
| Ongoing outbound at scale | Weekly |
| Before a high-volume campaign | 24–48 hours before launch |
| After a deliverability incident | Daily until 3 consecutive weeks pass with ≥90% inbox |
| After DNS or infrastructure change | Within 24 hours of the change |
Running a Test
- Go to Settings → Purchase Domain/Mailboxes
- Click a domain
- Open the Placement tab
- Configure the test (mailbox, frequency, receivers, content)
- Start the test
Results arrive within 5–15 minutes. graph8 sends a seeded email to test mailboxes in each provider and reports where it landed.
Reading Results
Test results show placement per provider:
| Provider | Inbox | Promotions | Spam | Other |
|---|---|---|---|---|
| Gmail | 95% | 2% | 3% | 0% |
| Outlook | 88% | — | 10% | 2% |
| Yahoo | 92% | — | 5% | 3% |
| iCloud | 90% | — | 7% | 3% |
| Column | What It Means |
|---|---|
| Overall score | Weighted average across all providers (B2B inboxes weighted higher) |
| Inbox | Delivered to primary inbox — the only “good” outcome |
| Promotions | Gmail-only tab; better than spam but filtered out of most reading sessions |
| Spam | Landed in junk folder — recipient unlikely to see it |
| Other | Quarantine, bulk, blocked, or not delivered |
Placement Score Benchmarks
| Overall Score | Health | Action |
|---|---|---|
| ≥95% | Excellent | Keep warmup running; send confidently |
| 85–94% | Healthy | Normal sending; monitor weekly |
| 70–84% | Warning | Reduce daily send volume by 30–50%; investigate content and list hygiene |
| 50–69% | Unhealthy | Pause outbound; resume warmup-only for 1–2 weeks |
| Below 50% | Critical | Stop sending from this mailbox; review DNS, content, list quality, and consider a new domain |
Diagnosing Low Placement
Match the symptom to the most likely cause:
| Symptom | Likely Cause | Fix |
|---|---|---|
| High spam rate across all providers | Domain reputation or content | Check content for spam triggers; slow ramp |
| Gmail inbox drops, others fine | Engagement with Gmail recipients is low | Increase reply rate in warmup; improve subject lines |
| Gmail moves emails to Promotions tab | Content looks promotional (images, tracking, CTAs) | Remove images/buttons; use plain-text format |
| Outlook spam spikes | SFB (smart network data) flagged your IP | Check SNDS score; consider pausing Outlook sending for a week |
| Yahoo/AOL bounce spike | Dedicated IP reputation issue | Check for hard-bounce volume; clean list |
| Corporate (B2B) domains reject | Missing DKIM alignment or strict DMARC policy | Verify DKIM is aligned; align From domain with DKIM domain |
Scheduled Tests
Set up recurring placement tests to catch deliverability issues early:
- In the placement test configuration, select Recurring
- Choose frequency (daily, weekly, bi-weekly)
- Set Alert threshold — if inbox drops below this, graph8 sends an email or Slack alert
- graph8 runs tests automatically and alerts you if placement drops
Scheduled tests count against your monthly test quota. See Settings → Billing for current quota.
Multi-Mailbox Rotation Testing
If you rotate across multiple mailboxes in a sequence, test each mailbox independently — placement varies per mailbox even on the same domain. Create one recurring test per mailbox and compare scores. Retire mailboxes that consistently score below 80%.
Best Practices
- Trust the automatic start — for purchased domains, warmup begins immediately on provisioning
- Don’t skip warmup on purchased domains — new domains have zero reputation
- Keep warmup running alongside outbound — warmup maintains reputation during active sending
- Monitor weekly — check the Warmup tab and run placement tests
- Use multiple domains — spread sending across domains to protect reputation
- Pause outbound before warmup — if reputation drops, stop outbound first; warmup-only sending recovers reputation faster
Troubleshooting
| Issue | Fix |
|---|---|
| Warmup not running for a new mailbox | Verify the mailbox is fully provisioned. The background worker enrolls mailboxes within 5–10 minutes of activation |
| Want to restart warmup manually | Open Settings → Purchase Domain/Mailboxes → [domain] → Mailboxes → [mailbox] → Warmup and adjust Settings |
| Low inbox placement | Reduce daily send volume in warmup settings, check DNS records (SPF, DKIM, DMARC), pause outbound for 1–2 weeks |
| Warmup paused unexpectedly | Check mailbox health — provider may have flagged the account. Reconnect OAuth if expired |
| Stats not updating | Click Refresh on the Warmup tab to pull the latest data from the warmup provider |
| Can’t find Warmup controls | Manual warmup management is only available for purchased mailboxes via Settings → Purchase Domain/Mailboxes. Self-connected mailboxes use automatic warmup only |
Related
- Mailboxes → - Connect and configure email accounts
- Domains → - DNS setup and domain management
- Purchase Domains → - Buy domains with auto-configured DNS