The best email deliverability tools are the ones that cover each job in the chain: warming new mailboxes, testing where real emails land, fixing authentication, watching blacklists, reading mailbox provider data and cleaning lists before you send. Warmy is the broadest single subscription we found, since it bundles warmup, placement tests, verification and DMARC monitoring. For the long version, read our Warmy review.
Some tool links here are affiliate links (disclosure). Nerdy Joe is an affiliate of Warmy, MailReach and Findymail, a certified Apollo.io Managed Services Partner and a PlusVibe Certified Silver Partner. We have no relationship with the other vendors below.
We have not tested these tools hands-on. Everything here comes from each vendor's own pages, read in November 2026, and accuracy or results claims are the vendors' own.
Email deliverability tools at a glance
Prices are list prices on monthly billing as of November 2026. "Not published" means the vendor's page did not show a figure.
| Tool | Main job | Best for | Free option | Starting paid price |
|---|---|---|---|---|
| Warmy | Warmup, placement tests, seed list, verification, DMARC | B2B and B2C senders who want one bundle | 7-day trial, free tools without sign-up | From $49 a month |
| MailReach | Warmup plus spam tests | B2B cold email teams | Free spam test, 3 a day | $25 per mailbox (1 to 5) |
| GlockApps | Inbox placement testing | Independent placement checks | 2 test credits | $59 a month |
| Mail-Tester | Single-address content and setup test | Quick free checks | 3 tests per 24 hours | Packs from $5 |
| EasyDMARC | DMARC reporting | Small teams moving to enforcement | Free lookup tools, trial | $44.99 a month |
| dmarcian | DMARC reporting | Teams that want low-cost DMARC data | Personal plan (non-business only) | $24 a month |
| Valimail Monitor | Sender visibility for your domain | A free first look at DMARC data | Free | Enforce: not published |
| MXToolbox | Blacklist monitoring and lookups | Ongoing blacklist alerts | 1 domain, weekly checks | $129 a month |
| Google Postmaster Tools | Gmail provider data | Anyone sending to Gmail | Price not stated by Google | Not applicable |
| Microsoft SNDS | Outlook.com IP data | Senders on their own IPs | Price not stated by Microsoft | Not applicable |
| Findymail | Finding and verifying emails | Teams that also need new contacts | 10 trial credits | $99 a month |
| ZeroBounce | List verification plus testing extras | Cleaning lists you already have | 100 credits a month | $39 for 2,000 credits |
How to choose: match the tool to the job
Each tool type watches one part of the chain. Pick by the gap you have, not by the longest feature list.
- Warmup builds sending history on new or quiet mailboxes.
- Placement testing shows where a real email lands at Gmail, Outlook and other providers.
- Authentication and DMARC confirms SPF, DKIM and DMARC pass and shows who sends as your domain.
- Blacklist monitoring tells you when your domain or IP appears on a list such as Spamhaus.
- Mailbox provider dashboards show what Google and Microsoft see about your real mail.
- List verification removes bad addresses before they bounce.
If you are not sure which of these is causing trouble, start with our guide to why emails go to spam, which walks through the diagnosis by cause.
Warmup tools
1. Warmy: best all-in-one subscription
Warmy describes itself as an email deliverability platform. Its warmup sends emails between your mailbox and its network, where Warmy says messages are opened, replied to about 30% of the time and moved out of spam. Warmy says its network has more than 1 million mailboxes (its FAQ cites at least 300,000).
It goes well past warmup. Warmy's own comparison pages say every plan includes placement tests, a seed list, Google Postmaster integration, DMARC monitoring, email verification and API access. It also positions for B2C as well as B2B, and it can warm ESP and transactional sending such as Mailchimp, SendGrid and Amazon SES, not only mailboxes.
Pricing: Warmy's comparison pages list five plans from $49 to $429 a month (Starter $49, Business $129, Premium $189, Expert $279, Platinum $429), priced by daily warmup volume, as of November 2026. Its pricing page itself shows only "from $49 a month", so confirm in the app. The trial is 7 days, one mailbox, no card.
Weaknesses, stated plainly:
- Warmy's own pages conflict on whether plan volume is shared across mailboxes or the $49 entry price is per mailbox. Confirm your mailbox slots before you buy.
- Its terms say fees are non-refundable and you must cancel at least five business days before renewal, through support.
- The warmup deliverability score is based on warmup emails, not your real campaigns.
- Its Health Score uses Google Postmaster reputation data, which Google says it is retiring (see the Postmaster section below).
Best for: teams that want warmup, testing, DMARC and verification under one bill, and B2C or ESP senders that cold-email-only tools do not cover. Our full Warmy review covers every plan and free tool.
2. MailReach: best simple warmup for B2B cold email
MailReach pairs automated warmup with a seed-list spam test. MailReach says its network has 30,000+ inboxes, mostly Google Workspace and Microsoft 365, and that it is built for B2B cold outreach rather than B2C newsletters.
MailReach's blog lists $25 per mailbox for 1 to 5 mailboxes, $19.50 for 6 to 20 and $18 for 21 to 50, as of November 2026, with 20% off annual billing. Every warmup plan includes 20 spam test credits, and the free spam test allows 3 tests a day with no card.
Weaknesses: no free trial of warmup is advertised, there is no refund for a started month, and its Reputation Score reflects where warming emails land, which MailReach itself says is not a readiness indicator. For a direct comparison, see Warmy vs MailReach, or our MailReach review.
Best for: B2B senders with 1 to 20 mailboxes who want warmup and placement tests without extra modules.
Built-in warmup in sequencers
If you already pay for a sequencer, you may not need a standalone warmup tool. Instantly, Smartlead and PlusVibe include warmup for unlimited mailboxes in their sending plans, from $47, $39 and $37 a month respectively as of November 2026. Standalone tools earn their place when you need placement testing, B2C or ESP warmup, or reporting that sits outside the sending tool.
A note on Google and warmup
Google's sender guidelines recommend increasing volume slowly to engaged recipients and do not mention warmup tools. Gmail's program policies prohibit automating Gmail in ways that mislead or deceive users. In 2023, GMass said Google required it to shut down its API-based warmup.
Warmy says it is not affected by those API restrictions and that its warmup emails stay inside its own network; its terms make customers responsible for following their email provider's policies. MailReach says Google has not banned warmup. Google has not published a position on warmup networks specifically.
Placement testing tools
Placement tests answer the question warmup scores cannot: where does my real campaign email land? Our inbox placement test guide explains how to run one properly.
3. GlockApps: best for independent placement tests
GlockApps is a placement testing tool with no warmup feature listed on its pricing page. The free tier gives 2 spam test credits. Essential costs $59 a month for 360 credits, Growth $99 for 1,080 and Enterprise $129 for 1,800, and the plans bundle DMARC analytics and IP monitors.
Best for: senders who want a testing tool separate from their warmup vendor, so the same company is not grading its own work.
4. Mail-Tester: best free quick check
Mail-Tester gives you one address to send to and returns a score out of 10 based on your message, server and IP. It allows 3 free tests per 24 hours, and paid packs start at $5 for 10 tests.
It is a content and configuration check, not a multi-provider placement test. Use it to catch broken authentication or spammy content, then use a seed-list test for placement.
Warmy and MailReach also offer free tests. Warmy's free deliverability test needs no sign-up and reports Inbox, Promotions, Spam and Unreceived by provider, plus the sending IP's blacklist status.
Authentication and DMARC tools
Gmail and Yahoo require SPF or DKIM from all senders and DMARC from bulk senders, and Microsoft now rejects non-compliant mail from high-volume senders to Outlook.com. DMARC tools read the aggregate reports providers send and show which services pass or fail.
5. EasyDMARC: best for moving to enforcement
EasyDMARC lists DMARC Plus at $44.99 a month ($35.99 billed yearly) for 2 domains, and DMARC Premium at $89.99 ($71.99 yearly) for 4 domains with a year of history. There is no free plan, but there is a free trial with no card and free DMARC and SPF lookup tools.
Best for: small teams that want guided reporting while they move from p=none to quarantine and reject.
6. dmarcian: best low-cost DMARC data
dmarcian has a $0 Personal plan for non-business use only (2 domains). Basic costs $24 a month ($19.99 billed annually) for 2 domains and 100,000 messages, and Plus costs $240 ($199 annually) for 8 domains. Paid plans have a 30-day trial with no card.
Best for: businesses that want plain DMARC reporting at a low entry price.
7. Valimail Monitor: best free sender visibility
Valimail offers Monitor for free, which shows the services sending email from your domain. Its paid Enforce and BIMI products do not publish prices. Free tools include a domain checker, DKIM checker, SPF validator and DMARC report analyzer.
Best for: a free first look at who sends as your domain before you pay for anything.
Warmy also includes DMARC monitoring in its plans, with alerts on new sending sources, and offers free SPF, DKIM and DMARC generators without sign-up. If you buy Warmy, you may not need a separate DMARC tool for a few domains.
Blacklist monitoring
8. MXToolbox: best for ongoing blacklist alerts
MXToolbox offers a free plan with 1 domain and weekly blacklist monitoring, plus free lookup tools for blacklists, SPF, DKIM, DMARC and MX records. Its Delivery Center costs $129 a month and adds 30 inbox placement tests, 5 domains and DMARC, SPF and DKIM analysis; Plus costs $399.
Best for: teams that want blacklist monitoring and lookups in one place.
For a one-off check, Warmy's free blacklist checker queries 25 lists at once, including Spamhaus, Barracuda and SpamCop, with no sign-up. Warmy says its paid reputation tracker monitors domains and IPs daily and alerts on new listings.
Mailbox provider dashboards
These are the only tools that show what a mailbox provider sees about your real mail.
9. Google Postmaster Tools: Gmail's view of your mail
Google Postmaster Tools monitors mail sent to personal Gmail accounts, with dashboards for spam rate, authentication and delivery errors. You verify your domain with a DNS TXT or CNAME record, and low-volume days may show no data. Google's help page does not state a price.
The reputation change: Google's help center says the old Postmaster Tools interface is being replaced by v2. "All old dashboards are available in v2 except the Domain and IP Reputation dashboards, which will be retired," and v2 adds a Compliance dashboard. Google says the deprecation was postponed and gives no dates.
Warmy's blog says those reputation views were "permanently removed". Either way, plan around spam rate, authentication and compliance data, not a reputation label. Tools that read Postmaster reputation, including Warmy's Health Score, may lose that input.
10. Microsoft SNDS: Outlook.com's view of your IPs
Microsoft SNDS (Smart Network Data Services) gives data about individual IPs and their reputation at Outlook.com, plus junk reporting and feedback loop settings. You sign in with a Microsoft account and request access to IPs you are responsible for.
It is IP-based, not domain-based, so it is most useful if you send from your own IPs. Microsoft's page does not state a price.
List verification
Bounces hurt sender reputation, and no warmup tool fixes a bad list. Warmy says so itself. Our email bounce rate guide covers the thresholds and fixes in order.
11. Findymail: best if you also need to find emails
Findymail finds and verifies emails in the same step, so found contacts do not need a second check, according to Findymail. Its verifier also checks outside lists at 1 verifier credit per check, and Findymail says it verifies catch-all domains that other tools mark risky or unknown.
New accounts get 10 free credits, and the $99 Starter plan includes 5,000 bonus verifier credits a month as of November 2026. Findymail says it refunds credits if your bounce rate exceeds 5%. Our Findymail email verifier guide has the details.
12. ZeroBounce: best for cleaning lists you already have
ZeroBounce offers 100 free validation credits a month, plus 1 inbox test and 1 blacklist monitor on the free tier. Pay as you go starts at $39 for 2,000 validations, and ZeroBounce ONE costs $99 a month (minimum 10,000 credits) with warmup seeds, placement tests, blacklist monitors and DMARC monitoring included. ZeroBounce claims 99.6% accuracy.
Warmy also includes verification. It labels catch-all, disposable and role addresses as Risky and claims 99.5% accuracy, with no published methodology. For more options, see our roundup of the best email verification tools.
Minimum stack by team size
These stacks use list prices as of November 2026 and assume you send cold or outbound email from Google Workspace or Microsoft 365. Free provider dashboards belong in every stack.
Solo founder or 1 to 3 mailboxes
- Warmup: your sequencer's built-in warmup, or MailReach at $25 per mailbox if your sequencer has none.
- Testing: Mail-Tester, Warmy's free deliverability test or MailReach's free spam test before each new campaign.
- Authentication: Valimail Monitor (free) plus Warmy's free DMARC and SPF generators to set records.
- Blacklists: MXToolbox's free weekly monitor.
- Provider data: Google Postmaster Tools.
- Verification: ZeroBounce's 100 free monthly credits, or Findymail if you also need new contacts.
Small team, 5 to 20 mailboxes
- Warmup and testing: Warmy Premium ($189 a month, if volume is shared as Warmy's comparison pages describe) or MailReach (10 mailboxes at $19.50 is $195). At about 10 mailboxes the two cost about the same, so choose on features.
- DMARC: included with Warmy, or dmarcian Basic at $24 a month alongside MailReach.
- Provider data: Google Postmaster Tools, plus SNDS if you use dedicated IPs.
- Verification: Findymail or ZeroBounce before every new list.
Our cold email infrastructure guide covers domain and mailbox setup for this size.
Agency or 20 to 50+ mailboxes across clients
- Warmup: Warmy Expert ($279) or Platinum ($429), which Warmy's own comparison says becomes cheaper than MailReach from about 20 mailboxes, if volume is shared. Warmy also offers up to 100 workspaces and free team members.
- Independent testing: GlockApps or MXToolbox Delivery Center, so placement checks do not come only from your warmup vendor.
- DMARC: Warmy's monitoring with a workspace per client, or EasyDMARC for client domains outside Warmy.
- Verification: a dedicated verifier sized to your monthly volume.
Agencies should also confirm resale terms. Warmy's terms restrict reselling the service while its agency features describe managing client mailboxes, so ask Warmy before you bill clients for it.
Bottom line
Start with the free tools: Postmaster Tools, SNDS if you own IPs, a free placement test and a free blacklist check. Verify every new list, because warmup does not fix bad addresses. Then pay for the bundle that fills your remaining gaps.
For most senders who want one subscription, Warmy covers the most jobs, with real caveats on pricing clarity and refunds. B2B teams with a handful of mailboxes may prefer MailReach's simpler per-mailbox price. Every caveat is in the complete Warmy review.
Rather not build the list yourself?
Nerdy Joe is owned by Agency Growth Partners (AGP). AGP builds verified lead lists and runs outbound for agencies, including the sending setup and deliverability work behind it. If you would rather hand that off, book a call with AGP.
Disclosure: My relationship with Instantly is that of an independent party. I do not hold any position, nor do I have the power to form binding agreements or act on behalf of Instantly. My earnings are derived from referral compensations provided by Instantly. The views I share are solely mine and should not be seen as official statements, promises, or representations of Instantly, or any related entities or personnel.
Sources
- Warmy homepage: https://www.warmy.io/
- Warmy pricing: https://www.warmy.io/pricing/
- Warmy vs MailReach comparison (plan table): https://www.warmy.io/compare/warmy-vs-mailreach/
- Warmy vs lemwarm comparison: https://www.warmy.io/compare/warmy-vs-lemwarm/
- Warmy email warmup product page: https://www.warmy.io/product/warm-up-email/
- Warmy FAQ: https://www.warmy.io/faq
- Warmy terms of service: https://www.warmy.io/terms-of-service/
- Warmy free deliverability test: https://www.warmy.io/free-tools/email-deliverability-test/
- Warmy free blacklist checker: https://www.warmy.io/free-tools/blacklist-checker/
- Warmy DMARC monitoring: https://www.warmy.io/product/dmarc-monitoring/
- Warmy email verification: https://www.warmy.io/product/email-verification/
- Warmy Health Score: https://support.warmy.io/knowledge/health-score
- Warmy workspaces: https://support.warmy.io/knowledge/warmy-workspaces
- Warmy on Google Postmaster Tools retiring: https://www.warmy.io/blog/google-postmaster-tools-retiring/
- Warmy on GMass and Gmail API restrictions: https://www.warmy.io/blog/why-warmy-is-the-best-gmass-alternative-for-warming-up-email/
- MailReach pricing: https://www.mailreach.co/pricing
- MailReach tier table (MailReach blog): https://www.mailreach.co/blog/warmup-inbox-pricing
- MailReach how warmup works: https://www.mailreach.co/how-email-warmup-works
- MailReach free spam test: https://www.mailreach.co/email-spam-test
- MailReach terms of use: https://www.mailreach.co/terms-of-use
- MailReach on Google and warmup: https://www.mailreach.co/blog/email-warmup-solutions-in-house-vs-third-party-services
- Instantly pricing: https://instantly.ai/pricing
- Smartlead pricing: https://www.smartlead.ai/pricing
- PlusVibe pricing: https://plusvibe.ai/pricing
- GlockApps pricing: https://glockapps.com/pricing/
- Mail-Tester: https://www.mail-tester.com/
- EasyDMARC pricing: https://easydmarc.com/pricing
- dmarcian pricing: https://dmarcian.com/pricing/
- Valimail pricing: https://www.valimail.com/pricing/
- MXToolbox Delivery Center: https://mxtoolbox.com/c/products/delivery-center
- Google Postmaster Tools help: https://support.google.com/a/answer/9981691?hl=en
- Google Postmaster Tools v2 changes: https://support.google.com/mail/answer/16594218
- Google email sender guidelines: https://support.google.com/mail/answer/81126?hl=en
- Gmail program policies: https://support.google.com/mail/answer/16734397
- GMass on shutting down warmup: https://www.gmass.co/blog/warmup-shutting-down/
- Microsoft SNDS: https://substrate.office.com/ip-domain-management-snds/snds
- Microsoft Outlook high-volume sender requirements: https://techcommunity.microsoft.com/blog/outlook/strengthening-email-security-outlook-new-requirements-for-high-volume-senders/4399730
- Yahoo sender best practices: https://senders.yahooinc.com/best-practices
- Findymail email verifier: https://www.findymail.com/email-verifier/
- Findymail pricing: https://www.findymail.com/pricing/
- ZeroBounce pricing: https://www.zerobounce.net/email-validation-pricing
Frequently asked questions
What are email deliverability tools?
They are tools that help your email reach the inbox instead of spam. The main types are warmup tools, inbox placement testers, authentication and DMARC tools, blacklist monitors, mailbox provider dashboards such as Google Postmaster Tools, and email verifiers that clean lists before you send.
What is the best email deliverability tool?
No single tool covers every job well. Warmy bundles warmup, placement tests, verification and DMARC monitoring in one subscription, MailReach is a simpler per-mailbox option for B2B cold email, and free provider dashboards like Google Postmaster Tools show data no paid tool can replace.
Is Google Postmaster Tools going away?
Not entirely. Google's help center says the old interface is being replaced by a v2 version and that the Domain and IP Reputation dashboards will be retired, while the other dashboards move to v2 and a new Compliance dashboard is added. Google says the deprecation was postponed and gives no dates.
Do I need a separate warmup tool if my sequencer has warmup?
Not always. Instantly, Smartlead and PlusVibe include warmup for unlimited mailboxes in their sending plans as of November 2026. A standalone tool like Warmy or MailReach adds features such as placement testing, B2C or ESP warmup, and separate reporting, which matter more for agencies and larger senders.
What is the difference between a placement test and a warmup score?
A placement test sends a real campaign email to a set of test inboxes and reports where it landed. A warmup score, as Warmy and MailReach describe theirs, reflects where warmup emails land inside the vendor's network, which is not the same as where your campaigns land.
Which free email deliverability tools are worth using?
Google Postmaster Tools and Microsoft SNDS for provider data, Mail-Tester or Warmy's free deliverability test for a quick check, Warmy's free blacklist checker or MXToolbox's free monitor, and Valimail Monitor for a free view of who sends from your domain.