A warmup program becomes more useful when you can explain what changed. MailSlurp puts sending activity, sender readiness and placement checkpoints in the program view, so you can review the evidence before changing the pace.

This guide is for that review: what the numbers mean, how to compare checkpoints, and what to do when the chart looks encouraging but one provider still reports spam. You'll also find a small worksheet for keeping the decision with the results.

## Start with the question each result answers

An increasing send count is easy to spot. Understanding what happened afterward takes a little more care.

| Observation | What it establishes |
| --- | --- |
| Accepted send | The configured sending provider accepted the outbound request |
| Controlled-inbox receipt | The message reached a monitored MailSlurp destination |
| Provider placement checkpoint | The sampled provider mailbox reported a placement outcome |
| Sender readiness | MailSlurp's current assessment and pacing guidance from available signals |

An accepted send doesn't turn into an inbox result simply because enough time has passed. A message can be accepted and later appear in spam, or remain unobserved during a check. Those outcomes remain useful evidence even though the accepted-send counter has already increased.

Daily controlled-inbox observations and premium provider placement also have different coverage. On eligible plans, warmup checkpoints sample Gmail, Google Workspace, Outlook.com and Microsoft 365. The [warmup documentation](/docs/email-warmup/) describes the available coverage. A result from one destination isn't a stand-in for another.

## Read the checkpoint before reading the percentage

In the program's **Inbox placement** section, MailSlurp shows placement over time and the latest available result, labeled **Baseline**, **Final** or a checkpoint day. The view includes checks sent, plus provider rows with inbox, spam and not-received counts.

A check still in progress isn't a completed zero-percent result. The chart uses completed or partial checks; partial coverage needs more care than a complete set of observations. If placement is unavailable, there's no placement conclusion to draw from that check.

For each review, it helps to record:

- which checkpoint and provider you're reading;
- whether the check is complete or partial;
- how many checks were sent and how many inboxes were sampled;
- the inbox, spam and not-received counts;
- whether the sender, connection or program settings changed between checks.

**Not received** describes a missing observation within the check. It doesn't tell you, by itself, that the message went to spam. Submission failures, delivery delays and observation issues call for different follow-up, so the activity and provider responses matter too.



{{LANDING_SHORTCODE:ARTICLE_IMAGE:%7B%22src%22%3A%22asset%3Aproduct%2Femail-warmup%2Fscreenshots%2Fplacement.png%22%2C%22alt%22%3A%22Example%20MailSlurp%20placement%20results%20with%20baseline%2C%20Day%207%20and%20Day%2014%20checks%2C%20reaching%2090%20percent%20in%20each%20sampled%20provider%22%2C%22width%22%3A%221920%22%2C%22height%22%3A%22848%22%2C%22mobileSrc%22%3A%22asset%3Aproduct%2Femail-warmup%2Fscreenshots%2Fplacement-mobile.png%22%2C%22caption%22%3A%22%22%7D}}



*Example data: the Day 14 check shows 9 inbox and 1 spam observation out of 10 for each provider. Both reach 90%, but neither has eliminated spam. These are illustrative samples, not customer results or a prediction for a campaign.*

## Compare the same provider across checkpoints

Let's use a deliberately small, hypothetical example. These are teaching numbers, not MailSlurp benchmark results or a customer report.

| Gmail sample | Baseline to later |
| --- | --- |
| Inboxes sampled | 4 to 4 |
| Inbox | 2 to 3 |
| Spam | 1 to 1 |
| Not received | 1 to 0 |

Counting inbox observations against all four sampled inboxes gives 50% at baseline and 75% later: an increase of **25 percentage points**. The improvement is one additional inbox observation, while the spam count is unchanged. That's a more useful description than declaring that spam has disappeared.

With four observations, one message moves the percentage by 25 points. Small samples can produce an impressive-looking line with very little movement underneath. Percentages do enjoy a bit of theatre.

MailSlurp's **Sender readiness** view includes provider placement changes, the baseline and latest inbox percentages, and the latest sample size when available. Those details help you ask whether an apparent improvement repeats across checkpoints. They don't establish that the same proportion of your subscribers will receive the next campaign in their inbox.



{{LANDING_SHORTCODE:POST_CTA_BANNER:%7B%22title%22%3A%22Follow%20the%20warmup%20beyond%20the%20send%20count%22%2C%22content%22%3A%22Review%20sender%20readiness%2C%20adaptive%20pacing%20and%20available%20provider%20placement%20checkpoints%20alongside%20your%20warmup%20activity%20in%20MailSlurp.%22%2C%22buttonHref%22%3A%22%2Fproduct%2Femail-warmup%2F%22%2C%22buttonText%22%3A%22Explore%20email%20warmup%22%2C%22buttonTheme%22%3A%22slate%22%2C%22image%22%3A%22asset%3Aproduct%2Femail-warmup%2Fscreenshots%2Fplacement-deltas-mobile.png%22%2C%22imageAlt%22%3A%22Example%20provider%20placement%20changes%20in%20the%20MailSlurp%20app%22%2C%22imageWidth%22%3A%22664%22%2C%22imageHeight%22%3A%22372%22%2C%22imagePosition%22%3A%22%22%7D}}



## Turn the review into a next step

The **Sender readiness** section shows **Ready for**, **Goal**, today's accepted and planned sends, and the next scheduled send. **Adaptive pacing** explains the current action and next target. An estimated goal date, when shown, is an estimate rather than a provider commitment.

The useful question is whether the observations support the next increase. Here's how a few common patterns translate into an investigation:

| Pattern | Useful next step |
| --- | --- |
| Repeated SMTP rejection | Investigate the connection or provider restriction before changing volume |
| Accepted sends, placement still pending | Wait for the checkpoint result before judging placement |
| One provider worsens across completed checks | Review that provider separately, including authentication and recent changes |
| A partial check differs sharply from a complete one | Compare coverage and counts before calling it a trend |
| Stable checks and an increase recommendation | Review the proposed target alongside normal production traffic |

MailSlurp also shows domain-health and Gmail reputation information when connected. Missing monitoring data is a gap in the evidence, not a healthy result. The program's explanation and recommended next step help put the available signals together.

For a sender already experiencing delivery problems, the [sender reputation recovery guide](/blog/email-sender-reputation-recovery/) gives a broader diagnosis process. Pausing a warmup during an investigation can keep a connection or configuration problem from producing more failed attempts.

## Keep a short record of the decision

This is a manual review template you can copy into a shared note. It uses the program view without assuming an export or calculating a new reputation score.

```text
Program, sender and review date:
Checkpoint label and status:
Provider / inbox / spam / not received:
Latest sample size and comparison checkpoint:
Changes to sender, connection or content since then:
Adaptive pacing action and explanation:
Other sending activity due before the next review:
Decision: continue, investigate, pause or revise schedule
Owner and next review:
```

A useful note might say, "Gmail gained one inbox observation; spam count unchanged; no connection change; review again after the next completed checkpoint." It says what happened and leaves the uncertainty visible. Someone picking up the program tomorrow won't need to reverse-engineer an enthusiastic tick mark.

## Test the campaign separately before sending it

Warmup content and campaign content do different jobs. MailSlurp warmup uses managed messages or a custom plain-text subject and body; custom warmup rejects links, tracking, media, scripts and template markers. Your finished campaign may contain all sorts of things that weren't present during the warmup.

A separate **inbox placement test** checks that actual message through the intended sending route. MailSlurp can reuse the verified sending connection for automated placement, while manual seed list testing provides the current test addresses and marker for a send from your email platform. The [inbox placement testing guide](/blog/inbox-placement-testing/) covers those steps and explains why Promotions differs from spam.

A message-level spam test, seed placement and sender reputation monitoring therefore complement one another. One inspects the message, one observes sampled mailbox outcomes, and one adds information about the sender over time. Together they give your email deliverability monitoring more context than a single score.

You can [create a MailSlurp account](https://app.mailslurp.com/sign-up/?onboardingRequest=deliverability) to start a warmup and follow the first observations. For an existing program, the next useful action is a review of its latest completed checkpoint, with the provider counts beside the percentage.