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See the Cold Email category →What Domain Warm-Up Actually Builds
Mailbox providers do not publish their exact recipient scoring algorithms, but the signals they observe are well understood. Sender reputation is a composite of:
- Spam complaint rate. Recipients who hit "Report spam." A domain above 0.1% complaints is in danger territory; above 0.3%, Gmail will start throttling delivery.
- Engagement. Opens (and especially replies), plus moves-to-inbox from the spam folder. These are the strongest positive signals.
- Bounce rate. Hard bounces suggest the sender is using stale or scraped lists. Above 2% is a red flag.
- Sending consistency. A domain that sends 800 emails on Monday and nothing until Friday looks like a blast operation. Even, predictable daily volume reads as legitimate.
- Domain age and history. The oldest, mildest signal. Even after warming up, a 30-day-old domain is treated with more suspicion than a 5-year-old one.
- Authentication. SPF, DKIM, and DMARC alignment provide bonuses to your reputation — and outright rejections when missing. A brand-new domain with broken authentication will not warm up no matter how carefully you ramp volume.
A brand-new domain has none of these signals in its favour. You start with effectively zero engagement, an unknown complaint rate, and zero history. The warm-up schedule is the process of populating those signals with positive data before you ask the domain to carry your full daily volume.
Week-by-Week Schedule
The schedule below assumes a brand-new domain with no authentication configured yet. Day 1 starts the day your DNS records are live and your sending infrastructure is ready. Drop volume if you see any of the warning signs in the next section.
| Week | Daily volume | Source mix |
|---|---|---|
| Week 1 | ≤ 20 | Personal contacts you already know. Plain-content messages, no images, no links. |
| Week 2 | 20–50 | Mix of warm personal contacts and low-risk opt-in recipients who have agreed to hear from you. |
| Week 3 | 50–100 | Begin introducing a small cold-outreach slice (10–20% of volume). Watch bounces and complaints closely. |
| Week 4 | 100–150 | Expand cold mix to 30–40% of volume. Confirm Gmail Postmaster domain reputation is "Medium" or "High" before scaling further. |
| Week 5 | 150–300 | Ramp toward target volume. Maintain a 70/30 mix of warm-to-cold. |
| Week 6+ | 300 → target | Continue ramp in 50-email-per-week increments until you hit your target daily send. |
The exact ramp curve depends on your target volume. If your goal is 500 emails per day, you can compress the schedule to ~4 weeks. If your goal is 5,000 emails per day (the Gmail bulk-sender threshold), expect 8–10 weeks and continue ramping gradually even after hitting your baseline.
Signals to Slow Down
Volume is not the only variable — your daily cap should be reduced if any of the following signals appear:
- Bounce rate above 2%. Your list has a hygiene problem. Pause the ramp and clean the list before resuming.
- Spam complaint rate above 0.1%. The gold-standard threshold. Above this, expect Google Postmaster reputation to degrade and inbox placement to drop.
- Gmail Postmaster domain reputation falling to "Low." A direct, real-time indicator that the algorithm has tagged you. Hold volume constant and audit content, list quality, and authentication before any further ramp.
- Open-to-spam-move ratio dropping. If opens fall while spam-folder-move rates climb, your content is probably triggering filters — not a volume issue, a copy issue.
- Sudden undelivered spike from a single ESP. If Microsoft or Yahoo start rejecting your messages, that ESP has flagged your domain. Pause and resolve before continuing.
Slowing down is always preferable to being blocklisted. If you are unsure whether to ramp, hold your current volume for another week; if signals are still positive, then continue the schedule.
How Inbox-to-Inbox Auto Warm-Up Helps
Auto warm-up services (also called "inbox-to-inbox" warm-up) work by routing a portion of your daily sends to a network of peer mailboxes that automatically open, reply to, mark-as-important, and move-from-spam your messages. The idea is to manufacture engagement signals at scale so the providers' algorithms see positive data tied to your domain during the early weeks.
What they do well:
- Generate consistent daily open and reply signals from real-looking mailboxes.
- Prevent messages you send to your real warm contacts from being spam-folder-moved by triggering positive engagement in the same network.
- Build negative-feedback tolerance: complaints are isolated to the warm-up network rather than affecting your real prospects.
What they don't do:
- Replace authentic engagement from real recipients — eventually you need real opens, real replies, and especially real positive moves-from-spam.
- Fix broken authentication. A domain with a missing DKIM record will not be rescued by warm-up alone.
- Substitute for content quality. Spam-trigger copy erodes the benefits of the warm-up network.
The right pattern is to layer auto warm-up on top of the manual schedule above: use it alongside a small daily send to real contacts in weeks 1–4, then taper the network share as you ramp toward your target volume. By month 2, your domain's engagement history is built from real recipients — which is what you actually need.
Compare with the checklist approach for cold email: Cold Email Deliverability → and confirm your domain isn't already blocklisted before any of this matters: Am I Blacklisted? →
Open the warm-up planner free
The ReputaPilot warm-up planner turns the schedule above into a checklist you can run against your real domain — your daily target, signals to watch, and weekly progression, all in one view.