# Domain & sending warm-up guide

> Build sender reputation by ramping volume gradually and mailing your most engaged recipients first. A practical schedule for new domains.

**Warming up** means starting at a low daily volume and increasing it gradually, so mailbox providers build a positive reputation for your domain before you send at full scale. A new domain has no track record — if it suddenly sends tens of thousands of messages, providers treat it like a spammer and route mail to junk.

MailBlastr sends on a shared IP pool, so the **IP** reputation is already warm. Your job is to warm up your **domain's** reputation — which is what Gmail, Outlook, and iCloud actually track for authenticated senders.

## The two rules of warm-up

1. **Ramp volume gradually.** Increase how much you send per day in steps, not all at once. Roughly doubling daily volume every few days is a reasonable pace; slow down if you see bounces or complaints rise.
2. **Send to engaged recipients first.** Start with the people most likely to open, click, and reply — recent signups and active customers. Positive early engagement is what tells providers your mail is wanted.

## New domain — first-week schedule

A brand-new domain has no reputation, so start very low and roughly double each day. These are baselines, not hard rules — slow down if your metrics worsen.

| Day | Messages per day | Messages per hour |
| --- | --- | --- |
| 1 | up to 150 | — |
| 2 | up to 250 | — |
| 3 | up to 400 | — |
| 4 | up to 700 | 50 max |
| 5 | up to 1,000 | 75 max |
| 6 | up to 1,500 | 100 max |
| 7 | up to 2,000 | 150 max |

Past day 7, keep increasing daily volume in steps (roughly ×1.4 per day is a safe pace for a new domain) until you reach your target, holding hourly volume to about a tenth of the daily figure.

## Existing domain — first-week schedule

If you're moving an already-established, already-warm domain onto MailBlastr, you can start higher and ramp faster:

| Day | Messages per day | Messages per hour |
| --- | --- | --- |
| 1 | up to 1,000 | 100 max |
| 2 | up to 2,500 | 300 max |
| 3 | up to 5,000 | 600 max |
| 4 | up to 5,000 | 800 max |
| 5 | up to 7,500 | 1,000 max |
| 6 | up to 7,500 | 1,500 max |
| 7 | up to 10,000 | 2,000 max |

Beyond day 7, continue stepping up (roughly ×1.5 per day for an established domain) toward your target daily volume.

## Watch these as you ramp

- **Bounce rate** — keep it **below 4%**. A rising bounce rate means list-quality problems; pause and clean before increasing volume.
- **Spam rate** — keep it **below 0.08%**. Any climb means slow the ramp and find the root cause before continuing.
- **Engagement** — opens (with the caveat that they're noisy), and especially clicks and replies.
- For Gmail, watch your domain reputation in **[Google Postmaster Tools](https://postmaster.google.com)** as you ramp.

> **Warning:** Avoid third-party "warm-up" services that artificially inflate engagement. They work by gaming spam filters, and as providers like Gmail adjust, that fake history backfires on your real reputation. Warm up with real, relevant mail to engaged recipients instead.

## After warm-up: stay consistent

Reputation decays when you go quiet. After warming up, keep a **steady** cadence rather than long silences punctuated by big blasts — a sudden burst after weeks of nothing looks like a fresh, cold sender all over again.

> **Note:** Warm-up and authentication go together: a domain can only build reputation once it passes SPF/DKIM and aligns with DMARC. Verify your domain and publish DNS first — see [DNS records](https://www.mailblastr.com/docs/domains/dns).