What is the difference between deliverability monitoring and email warmup?

Warmup builds a mailbox's sender reputation over time by trading real-looking mail with a network of other inboxes. Monitoring is a check that tells you where a send landed at each provider: inbox, promotions or spam. Most teams need both.

Is Google Postmaster Tools enough on its own?

It's free and shows Gmail data: spam rate, domain reputation and IP reputation. That helps, since Gmail is often the biggest slice of a B2B list. It only covers Gmail, though, so it misses problems at Outlook, Yahoo or company spam filters that a seed-list tool would catch.

How often should deliverability be checked during an active campaign?

Check at least weekly while you send steadily. Check right away after you change volume, add a new domain to the pool, or see a jump in bounces or complaints. Those are the events most likely to move a domain's reputation.

Does SalesCrew include deliverability monitoring?

Disclosure: SalesCrew is our product. It tracks bounce and complaint rates per mailbox and moves a mailbox to suppression when they spike. Pair it with a seed-test tool like GlockApps to see inbox placement.

Best deliverability monitoring tools

Bounce and complaint rates tell you a problem happened. A monitoring tool tells you where a message landed, before a dead campaign tells you the hard way.

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Pipeline with weighted forecast and stage breakdown

GlockApps wins for a team that wants inbox placement tests across many providers in one dashboard. Google Postmaster Tools wins as a free add-on for the Gmail slice of your list.

The short answer

GlockApps' Essential plan starts at $59/mo and tests inbox placement across 70-plus seed addresses at Gmail, Outlook, Yahoo and company filters.
Google Postmaster Tools is free and shows domain reputation, IP reputation and spam rate, but only for mail sent to Gmail, not the rest of a mixed B2B list.
Warmup and monitoring answer different questions. Warmup builds reputation before you send at volume; monitoring tells you what happened to a message you already sent.
These tools find the problem. The fix is usually to slow your send volume, clean your list, or take a burned domain out of rotation.

How we compared these

We compared tools on what they test (inbox placement at which providers, spam scores, reputation), on starting price, and on whether the tool is free, sold alone, or bundled with warmup. We checked each vendor's pricing page in September 2026.

Deliverability monitoring comparison

Tool	Starting price	What it tests	Provider coverage	Best for	Not for
GlockApps	$59/mo Essential (annual billing), unlimited spam tests	Inbox placement, spam scores, blacklist checks	70+ seed addresses across Gmail, Outlook, Yahoo, company filters	A team that wants one dashboard for most major providers	A team that only cares about Gmail and doesn't want a paid tool
Google Postmaster Tools	Free	Domain reputation, IP reputation, spam rate, feedback loop data	Gmail only	Any sender, as a free base check on the largest single provider	A full picture across Outlook, Yahoo or company spam filters
Mailreach	$19.50/mailbox/mo, All-In-One plan (warmup plus 20 spam-test credits)	Warmup plus monitoring in one plan	Several major providers through its spam-test credits	A team that wants warmup and monitoring from one vendor	A team that already has a warmup tool and only wants monitoring

Figures checked on vendor pricing pages, September 2026, including mailreach.co/pricing.

The field, ranked

1. GlockApps

Inbox placement tests across dozens of real seed addresses, with a spam-score breakdown for each test. It's the clearest single-job tool here. Best for: a team running steady cold outbound that wants a weekly placement check. Not for: a team on a tight budget that sends now and then.

2. Google Postmaster Tools

Free and straight from Gmail, with domain and IP reputation data that no outside tool sees as clearly. Best for: any sender, as a base check that costs nothing. Not for: full coverage; it says nothing about Outlook or Yahoo placement.

3. Mailreach

Puts warmup and monitoring in one $19.50/mailbox/mo plan, for a team that wants fewer vendors more than the deepest tool in either job. Best for: a smaller team cutting down its tools. Not for: a team that wants the most detailed placement data; a single-job tool usually goes deeper.

How to choose

Choose GlockApps if you run steady cold outbound and want weekly placement tests across 70-plus seed addresses. Add Google Postmaster Tools for free Gmail data whatever else you use. Choose Mailreach if you want warmup and monitoring from one vendor. Monitoring pays off once you send from a second domain and a sender pool, where one bad domain can quietly drag down replies for weeks.

Questions

What is the difference between deliverability monitoring and email warmup?: Warmup builds a mailbox's sender reputation over time by trading real-looking mail with a network of other inboxes. Monitoring is a check that tells you where a send landed at each provider: inbox, promotions or spam. Most teams need both.
Is Google Postmaster Tools enough on its own?: It's free and shows Gmail data: spam rate, domain reputation and IP reputation. That helps, since Gmail is often the biggest slice of a B2B list. It only covers Gmail, though, so it misses problems at Outlook, Yahoo or company spam filters that a seed-list tool would catch.
How often should deliverability be checked during an active campaign?: Check at least weekly while you send steadily. Check right away after you change volume, add a new domain to the pool, or see a jump in bounces or complaints. Those are the events most likely to move a domain's reputation.
Does SalesCrew include deliverability monitoring?: Disclosure: SalesCrew is our product. It tracks bounce and complaint rates per mailbox and moves a mailbox to suppression when they spike. Pair it with a seed-test tool like GlockApps to see inbox placement.