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# Email Warming Overview

# Email Warming Overview

## Purpose

New mailboxes can't send 500 emails a day on day one — they get flagged as spam. Warming gradually builds a sending reputation by starting low and increasing volume over time, establishing your mailbox as a legitimate sender. This article explains how warming works in SuperSend and what to expect from the warming dashboard.

## Why Warming Matters

When you connect a fresh mailbox to a sending campaign, email providers like Google and Microsoft are watching. A new mailbox that immediately blasts hundreds of emails looks like spam activity. Warming solves this by:

1. Starting with a small daily send volume (e.g., 5–10 emails/day).
2. Gradually increasing volume each day over a 14-day initial warmup period.
3. Running "background warming" indefinitely after the initial period — a low-volume stream of warm-up emails that keeps the mailbox's reputation active even on days when your campaigns don't send much.

The warming emails are real messages exchanged with a network of other warming mailboxes. They land in inboxes, get opened and replied to, and simulate healthy inbox activity.

## The Two Warming Phases

**Initial Warmup (Day 1–14)**
This is the ramp phase. SuperSend limits daily sending from the mailbox and gradually increases it. The warming dashboard shows "Day 7 of 14" or similar for each mailbox in this phase. Most mailboxes complete initial warmup within two weeks.

**Background Warming (After Day 14)**
Once initial warmup completes, the mailbox shifts to background warming. SuperSend continues sending a low volume of warming emails daily, maintaining reputation. Background warming runs indefinitely unless you turn it off. Mailboxes in background warming show a green "Background" badge on the warming dashboard.

When a mailbox finishes initial warmup and is in a healthy state, the dashboard shows a **"Ready to Go!"** banner. At this point, it's safe to ramp your campaign sends.

## The Warming Dashboard

Go to **Warming** from the left sidebar.

### Stat Cards

At the top of the page, three summary cards give you a snapshot:

| Card | What it shows |
|---|---|
| **Total Warming** | Total mailboxes currently warming, broken down by Initial vs Background |
| **Avg Health Score** | Average health score across all warming senders. Green ≥80%, yellow ≥60%, red <60% |
| **Inbox Rate** | The percentage of warming emails landing in the inbox (vs. spam). From placement test data. Green ≥95%, yellow ≥90%, red <90% |

### Status Filter Tabs

Below the stat cards, filter the sender list by:
- **All** — shows every mailbox currently in warming
- **Initial Warmup** — just the mailboxes in the 14-day ramp phase
- **Background** — mailboxes that have completed initial warmup and are maintaining

### The Warming Chart

Two views, toggled by tabs:

**Initial Warmup view**
A bar chart showing how many senders are on each day of the 14-day warmup. If you added a lot of mailboxes at once, you'll see a cluster of bars. Hover over a bar to see the breakdown of healthy vs. unhealthy senders on that day.

**Trends view**
A dual-axis line chart for the selected time period. The purple line tracks total warming email volume; the green line tracks inbox rate (%). Use this to spot when inbox rate drops — usually a sign that content or volume needs adjustment.

Use the **period selector** (top right of the chart) to view Last 7 / 14 / 30 / 60 / 90 days.

### The Warming Senders Table

A full list of every mailbox in warming with these columns:

| Column | What it shows |
|---|---|
| **Email** | Mailbox email address. Red ⚠ icon if this sender is flagged as a problem |
| **Status** | "Initial" (purple) or "Background" (green), with current day/progress |
| **Progress** | Progress bar for Initial warmup senders showing how far through the 14-day ramp |
| **Inbox Rate** | % of warming emails landing in inbox. Color-coded. |
| **Health** | Overall health score. Color-coded. |
| **Volume** | Sent today / Max per day. E.g., "12/50 /day" |
| **Profile** | The sender profile this mailbox is attached to (link) |

**Actions per row:**
- **Hide button** — removes the mailbox from the list after background warming completes. Doesn't stop warming — just hides it from this view.
- **Settings (gear) icon** — opens the sender settings modal to adjust warming speed, daily limits, SMTP settings, and other configuration.
- **Chart (bar) icon** — expands an inline 30-day history chart for that individual mailbox.

## Inbox Placement by Provider

When warm-up placement data is available, the dashboard shows a row of pills for **Google**, **Outlook**, and **SMTP** (all other mailbox types combined). For example: *"Google: 97.3% (1,204)"* — meaning 97.3% of warming emails sent to Google-hosted addresses landed in the inbox, based on 1,204 messages.

This is the most useful signal for understanding where your mailboxes actually land. If Google shows 94% but Outlook shows 71%, you know to investigate before sending a campaign heavily targeting Outlook-hosted companies. **Placement tests** (separate from warm-up) can still break results down further by provider when you need seed-level detail.

## Expected Result

You can see the warming status of every mailbox, identify which ones are ready to use, and spot any with health problems before assigning them to active campaigns.

## Troubleshooting

- **Issue:** Warming data appears flat (no health score, no inbox rate).  
  **Fix:** Confirm the mailbox is connected and actively sending warming emails. Go to Senders → Mailboxes and check the mailbox status. Warming data typically starts appearing within 24 hours of activation.

- **Issue:** A mailbox shows "Problem" status.  
  **Fix:** Click the gear icon on that row to open sender settings. Check if the mailbox connection is still active (SMTP/IMAP auth valid). Common causes: password change on the underlying mailbox, IMAP access disabled, or sending limits hit at the provider.

- **Issue:** Inbox rate is declining over time.  
  **Fix:** Reduce campaign volume on that mailbox and let warming run longer before ramping back up. Also run a placement test to get more diagnostic data.

## Related Articles

- [Understand Sender Health](https://help.supersend.io/en/article/understand-sender-health-3vg2oi/)
- [Placement Tests Overview](https://help.supersend.io/en/article/placement-tests-overview-1bhvhlu/)
- [Senders Overview](https://help.supersend.io/en/article/senders-overview-vqg87v/)