Best Email Deliverability Tools for Cold Email (2026)

Here's a conversation I've had more times than I'd like. A company comes to us after its last outbound attempt. "Our emails were going to spam," they say. I ask how they know. Usually the answer is: open rates fell off a cliff.

Then I look. Open tracking was on, so every email carried a tracking pixel and a tracking domain. Mailboxes went from zero to 50 cold emails a day in their first week. Nobody had checked SPF, DKIM or DMARC since the domain was bought. And the list hadn't been verified, so bounces were climbing every day.

No tool was going to save that. But tools would have shown them the problem two weeks earlier, before the domain's reputation was gone.

This guide covers the deliverability tools that actually help with cold email: monitoring, placement testing, warmup and DNS checks. I'm Rodrigo, co-founder of Romar AI. We manage sending for every client on dedicated domains, and I'll say what we use. Every price is from the vendor's own page, checked on November 13, 2026.

Top 8 email deliverability tools in 2026

What does cold email deliverability involve?

• Separate sending domains. Never your main domain. Each with SPF, DKIM and DMARC set up correctly.
• Warmup. New mailboxes send small amounts and get engagement before they cold-send. We warm for 14 days, then start at 10 cold emails a day per mailbox, then 20.
• Low volume per mailbox. Many mailboxes each sending a little beats a few sending a lot.
• Clean lists. Every address verified. We pause a campaign if bounces pass 2% after 100 sends.
• Tracking off. No open or click tracking, which adds pixels and redirect links that filters notice.
• Monitoring. Reputation, spam rate and placement, checked regularly.
• Plain emails. Short, few or no links, no images. Our first emails carry zero links.

Tools help with the first, second and last of those. The middle ones are discipline. I have yet to find software that stops a founder from uploading a list he bought on a forum.

1. Google Postmaster Tools: Best for a free view of Gmail reputation

Google Postmaster Tools shows how Gmail sees mail from your domain.

Key features

• Dashboards for spam rate, domain and IP reputation, authentication and delivery errors.

Pricing

Free.

Where Postmaster Tools shines

• It's Gmail's own data, which is as close to the truth as you get.

Where Postmaster Tools falls short

• Data only covers mail to personal Gmail accounts, not Google Workspace business inboxes, and only appears once you send enough volume. For B2B cold email, that means it's a partial view.

Who Postmaster Tools is best for

Everyone. Set it up on every sending domain. It costs nothing.

2. Instantly warmup: Best for teams already on Instantly

Instantly includes warmup on its outreach plans, alongside unlimited email accounts.

Key features

• Unlimited warmup on outreach plans.
• Warmup runs inside the same tool you send from.

Pricing

Included in Instantly's outreach plans: Growth $47 a month, Hypergrowth $107, Light Speed $358 (monthly billing).

Where Instantly warmup shines

• No extra tool and no extra bill.
• Why we use it: at Romar AI we warm every new mailbox in Instantly for 14 days before it sends a single cold email. We're an Instantly Solutions Partner.

Where Instantly warmup falls short

• It's warmup, not testing. You still want an occasional placement test from another tool.

Who Instantly warmup is best for

Teams sending on Instantly.

3. GlockApps: Best for placement tests plus DMARC reports

GlockApps runs inbox placement tests and DMARC analytics.

Key features

• Spam test credits to see where your emails land across providers.
• DMARC analytics, uptime monitors and IP reputation monitors.

Pricing

Free (2 spam tests). Essential $59 a month, Growth $99, Enterprise $129, billed monthly. Annual billing saves 30%.

Where GlockApps shines

• Testing and DMARC in one place at a reasonable price.

Where GlockApps falls short

• Seed-based placement tests are a sample, not your real recipients. Treat results as a smoke alarm, not a census.

Who GlockApps is best for

Teams that want regular tests and DMARC reports without two vendors.

4. MailReach: Best for per-mailbox warmup with spam tests

MailReach sells warmup per mailbox and spam test credits.

Key features

• An all-in-one plan with warmup and at least 20 spam test credits included.
• A separate spam tester.

Pricing

Priced on a slider by mailboxes. When I checked, the slider showed $19.50 per mailbox per month on the all-in-one plan at its default setting.

Where MailReach shines

• Spam tests come with warmup, so you test as you go.

Where MailReach falls short

• Per-mailbox pricing adds up when you run many mailboxes, and sending tools already include warmup.

Who MailReach is best for

Teams on a sending tool without good warmup.

5. Warmy: Best for warmup with expert help

Warmy is a warmup and deliverability platform.

Key features

• A network it describes as 1M+ mailboxes, and a US seed list.
• Pulls Google Postmaster data, and includes list verification and DMARC monitoring.
• A dedicated deliverability expert, per its site.

Pricing

Plans from $49 a month, with a 7-day trial.

Where Warmy shines

• Human help, which is rare.

Where Warmy falls short

• Another warmup layer on top of a sending tool that already warms.

Who Warmy is best for

Teams that want someone to talk to about deliverability.

6. Folderly: Best for free placement tests

Folderly sells inbox placement testing and mailbox deliverability products.

Key features

• Placement tests that check where emails land, plus IP and DNS checks.
• Real-time spam placement alerts.

Pricing

Placement tests: Free (2 tests a month), $79 a month for 100 tests. Its mailbox product was $96 per mailbox per month on yearly billing when I checked.

Where Folderly shines

• A free tier that's enough for a pre-launch check.

Where Folderly falls short

• The mailbox product is expensive for cold email at volume.

Who Folderly is best for

Teams that want a quick, free test before launching.

7. MXToolbox: Best for DNS and blacklist checks

MXToolbox is a long-running set of DNS, email and blacklist tools.

Key features

• Free lookups for MX, SPF, DKIM, DMARC and blacklists.
• Delivery Center for monitoring.

Pricing

Free tools. Delivery Center $129 a month, Delivery Center Plus $399 a month.

Where MXToolbox shines

• The free lookups are the quickest way to check a new domain's setup.

Where MXToolbox falls short

• Blacklist checks matter less for cold email on Google Workspace or Microsoft 365, where reputation is mostly domain-based.

Who MXToolbox is best for

Anyone setting up domains.

8. Allegrow: Best for catch-all checks plus monitoring

Allegrow combines verification, including catch-all addresses, with deliverability monitoring.

Key features

• Catch-all verification with conclusive valid or invalid statuses, per its site.
• Spam trap detection, SPF, DKIM and DMARC monitoring.

Pricing

A free tier for up to 1,000 verifications, a 14-day trial, and Starter at $99 a month with 5,000 credits.

Where Allegrow shines

• Catch-all handling, which matters with small ecommerce brands.

Where Allegrow falls short

• More expensive per check than pure verifiers.

Who Allegrow is best for

Teams with many catch-all domains and a need for monitoring.

What I check first when someone says "we're in spam"

Before anyone buys a tool, I go through the same short routine. It takes about 20 minutes and catches most problems.

First, the domain. Is the campaign sending from the company's main domain? If yes, that's the conversation, and nothing else matters until it's fixed.

Second, authentication. SPF, DKIM and DMARC on every sending domain, checked with a free lookup. A surprising number of setups have SPF records that include three old tools nobody uses anymore, which can break the record entirely.

Third, volume per mailbox. If a mailbox is sending 60 or 80 cold emails a day, that's the problem, or at least a big part of it. Spread the same volume across more mailboxes and domains.

Fourth, bounces. Pull the last 500 sends and count. If bounces are over 2%, the list is the problem, not the content.

Fifth, the email itself. Links, images, tracking, a signature with five social icons. Strip it down. A plain email of 90 to 150 words, with no links in the first one, looks like a person wrote it, because a person should have.

Only after those five do I look at placement tests and reputation dashboards. Tools tell you something is wrong. These five things usually tell you what.

Why "open rate" is a bad deliverability signal

Apple Mail Privacy Protection preloads images, which fires tracking pixels whether a human opened the email or not. Some corporate filters do the same when they scan links and images. So open rates can be inflated in some places and missing in others, and either way they're noisy.

We run with tracking off and judge campaigns on replies: how many, and how many are real people rather than autoresponders. It's a slower signal, and a much more honest one. If a segment gets zero human replies over a few hundred sends to verified addresses, either the email is wrong or it isn't landing, and a placement test will tell you which.

How to choose deliverability tools

1. Start with free

Postmaster Tools and MXToolbox cost nothing. Use them first.

2. Don't stack warmup

If your sending tool warms (Instantly, Smartlead, Saleshandy all do), you probably don't need another.

3. Test before launch, then monthly

A placement test before each new campaign and once a month is enough for most teams.

4. Fix the basics before buying tools

Separate domains, authentication, low volume per mailbox, verified lists, tracking off. No tool fixes the absence of these.

5. Watch bounces most

Bounce rate is the earliest warning. Set a pause rule (ours is 2% after 100 sends) and stick to it.

How much do deliverability tools cost in 2026?

Or have deliverability handled for you

At Romar AI we set up and run deliverability for every client: dedicated domains, authentication, 14 days of warmup, 10 then 20 sends a day per mailbox, verified lists, tracking off and a pause at 2% bounces. Your main domain never touches cold email. We send the cold email, answer the replies and book the meetings on your calendar. Start with a trial, then a full program priced on the call.

Book a call with Romar AI.

So, which deliverability tools should you use?

For most cold email teams: Google Postmaster Tools and MXToolbox (free), the warmup built into your sending tool, and a placement tester like GlockApps or Folderly once a month. Add Allegrow if catch-all addresses are a big part of your list.