What does an email deliverability service do?
An email deliverability service checks and monitors whether your email reaches inboxes. The market splits into five jobs, and a small B2B team usually needs two or three of them rather than one big suite. Every price below comes from the vendor's own page, in US dollars, checked on 4 November 2026.
| Job | What it answers | Free starting point | Paid examples |
|---|---|---|---|
| Provider dashboards | How Gmail, Yahoo and Microsoft see your mail | Google Postmaster Tools, Yahoo Sender Hub, Microsoft SNDS | None; no price is listed on any of the three sites |
| Placement and setup tests | Which folder a test email reaches, and why | mail-tester (3 tests per 24 hours), GlockApps Free (2 test credits) | GlockApps, MxToolbox Delivery Center, EasyDMARC Deliverability |
| DMARC reporting | Who sends mail as your domain, and whether it passes | Postmark's weekly digest, dmarcian Personal (non-business use) | dmarcian, EasyDMARC, Postmark DMARC Digests |
| List verification | Whether an address will bounce before you send | ZeroBounce: 100 free validations a month with a business domain sign-up | ZeroBounce |
| Consulting | Why mail is failing and what to change | Postmaster Tools' delivery issue form, Microsoft sender support | GlockApps with MailSoar, MxToolbox Managed Services, dmarcian |
Warm-up tools are a separate category with their own trade-offs; our sibling post on email warm-up and the tools that do it covers them. To run a test with the free tools below, follow our step-by-step email deliverability test.
Which free deliverability tools come from Gmail, Microsoft and Yahoo?
Gmail, Microsoft and Yahoo each run a sender tool with no price listed, and each has one condition that decides whether it's any use to a small team.
| Tool | What you get | Who can use it | The catch |
|---|---|---|---|
| Google Postmaster Tools | Compliance status, spam rate, authentication, encryption, delivery errors and feedback loop dashboards | Anyone with a Google account who verifies the sending domain with a DNS record | Covers mail to personal Gmail accounts only, and data may be missing on low-volume days |
| Microsoft SNDS | Per-IP mail volume, filter results and complaint reports, plus the Junk Mail Reporting Program | People who can prove they own the IP range | Data may be missing for IPs that sent fewer than 100 messages that day; access lasts 10 months, then needs reattestation |
| Yahoo Sender Hub | Complaint Feedback Loop reports for your DKIM domain, and Insights with aggregated delivery statistics | Senders who add and verify their domains | Yahoo's FAQ says it no longer offers IP-based feedback loop reports |
The deciding fact is where your mail leaves from. If you send through Google Workspace or Microsoft 365, the sending IPs belong to Google or Microsoft, so in our reading you have no range to prove to SNDS; its welcome page pitches it to people monitoring the IPs they control. Set up Postmaster Tools first. Google's setup page says verification usually works right away but can take up to 10 minutes.
Two details from Google's own pages change how you use it. Google's page on retiring the old interface (a retirement Google has now postponed) says the Domain and IP Reputation dashboards won't move to the new version and will be retired, partly because the old dashboard can be misleading when reputation is only one of many factors affecting deliverability. And for DMARC, Google's sender requirements FAQ says to use a third-party DMARC tool to check the details, which is why the DMARC reporting row above exists.
How much do email deliverability tools cost?
From $0 to a few hundred dollars a month for small teams, and on request at enterprise level. This table compares the pricing basis and the lowest paid price each vendor shows.
| Tool | Main job | Pricing basis | Lowest paid price shown | Free option |
|---|---|---|---|---|
| mail-tester | Setup and content score | Per test | $5 for 10 tests, or $10 a month for 50 (excl. VAT) | 3 tests per 24 hours |
| GlockApps | Seed placement tests, DMARC, uptime | Plan with spam test credits | Essential: $85 a month with 30 credits (taxes may apply), or $59 a month billed annually ($708) with 360 | Free plan, 2 credits |
| MxToolbox | Blacklist monitoring, placement, DMARC | Monthly plan by domains and volume | Delivery Center: $129 a month, 30 inbox placement analyses, 5 domains | Weekly blacklist monitoring for 1 domain |
| Postmark DMARC | DMARC reports | Per domain | $14 a month per domain, 14-day trial | Weekly email digest: top 10 sources, 5 IPs each |
| dmarcian | DMARC management | Plan by domains and messages | Basic: $24 a month billed monthly, or $239.88 a year, excl. taxes; up to 2 domains and 100,000 DMARC-capable messages a month | Personal plan, non-business use only |
| EasyDMARC | DMARC; its Deliverability tier (custom price) adds inbox placement tests | Plan by emails a month and domains | DMARC Plus: $44.99 a month, or $35.99 a month billed annually; 2 domains, 100,000 emails a month | Free trial, no card |
| ZeroBounce | List verification | Credits, one per address checked | $39 for 2,000 validations, or ZeroBounce ONE at $99 a month | 100 free validations a month (business domain sign-up) |
| Validity | Enterprise placement and monitoring | Custom quote | Not shown | None shown |
Three notes on reading it. GlockApps counts one test as one email sent to its full or shortened seed list, whatever the number of seeds. ZeroBounce says it doesn't charge for "unknown" results, and that without a ZeroBounce ONE subscription, credits may expire depending on when your account was created or the credits were bought. Validity's pricing page offers "Enterprise pricing, built to fit," and the old Everest address now opens a Validity Engage page.
What does a deliverability stack cost a three-mailbox team?
About $20 a month for the lean version and $105 to $150 for paid monitoring. Here is the arithmetic for a sample team, Northwind Ltd (an invented example): two founders, three Google Workspace mailboxes on one domain, about 40 cold emails a day per mailbox, and 1,000 new leads a month to verify.
| Item | Lean stack | Placement-test stack | Suite stack |
|---|---|---|---|
| Provider dashboards | $0 | $0 | $0 |
| Placement or setup tests | mail-tester free tier: $0 | GlockApps Essential, monthly: $85 | MxToolbox Delivery Center: $129 |
| DMARC reports | Postmark free digest: $0 | Included in GlockApps Essential: $0 | Included in Delivery Center |
| Verification | ZeroBounce: $19.50 | ZeroBounce: $19.50 | ZeroBounce: $19.50 |
| Per month | $19.50 | $104.50 | $148.50 |
The workings. Verification: $39 buys 2,000 checks, so 1,000 a month costs $39 ÷ 2 = $19.50 a month on average, before ZeroBounce's 100 free monthly validations. Tests: one test per mailbox a week is 3 × 52 ÷ 12 = 13 a month, which fits inside mail-tester's free 3 per 24 hours and inside the 30 credits on GlockApps' monthly Essential plan. Annual billing changes the GlockApps line: $85 × 12 = $1,020 a year against $708, a saving of $312. Placement stack: $85 + $19.50 = $104.50, because GlockApps Essential includes DMARC Analytics for up to 50,000 DMARC messages a month. Suite: $129 + $19.50 = $148.50.
At 3 × 40 = 120 emails a day, much of it to company domains rather than personal Gmail, Postmaster Tools may show little data, so the test line matters more than the dashboards. If Siela's Lead Finder sends Northwind's cold email, it goes from the Gmail mailboxes Northwind connects, up to 100 a day each, so the same stack applies to those mailboxes.
Which deliverability tool fits which problem?
Match the tool to the symptom, and start with the free check in the middle column.
| Symptom | Check first (free) | Pay for this if the free check doesn't settle it |
|---|---|---|
| Gmail rejects mail with a 5.7.26 error | Authentication: Google says messages that aren't authenticated may be rejected with that error | DMARC reporting, to find which sending service fails |
| Replies dried up on a sequence that used to work | One test send with headers read at Gmail and Microsoft 365 | Seed placement tests across providers |
| New domain or mailbox | DNS checks, then a slow ramp | A weekly placement test during the ramp |
| Bounces rising on new lists | Remove addresses that hard-bounced | List verification before each upload |
| Mail to Microsoft 365 prospects lands in Junk | The SFV and CAT values in a test header | Placement tests that include Microsoft seeds |
| About 5,000 or more a day to Gmail | Postmaster Tools' Compliance status dashboard | DMARC monitoring: Google requires DMARC at that volume |
Two volume lines matter. Google calls a bulk sender anyone who sends about 5,000 messages or more to Gmail accounts in 24 hours, and its sender guidelines require SPF, DKIM and DMARC above 5,000 a day. Microsoft's Outlook.com postmaster page says that since 5 May 2025 it has enforced SPF, DKIM and DMARC for domains sending over 5,000 emails a day, with non-compliant mail sent to Junk. For a quick look at your own record, our DMARC checker reads its policy and where reports go. If the cause turns out to be the sending tool itself, our Instantly, Smartlead and lemlist comparison covers the sending side.
When should you hire an email deliverability consultant?
When the free checks pass and placement is still poor, or when mail that brings in revenue is blocked and you can't find the cause. The vendor services we found: GlockApps books calls with consultants from its partner MailSoar and says you get a recording of the session (GlockApps consulting page); MxToolbox offers Managed Services covering inbox placement, blacklist monitoring, SPF and DKIM setup and DMARC enforcement; ZeroBounce and dmarcian list consulting and DMARC deployment services in their menus. Only GlockApps listed a price when we checked on 4 November 2026: a free 20-minute assessment, or a 1-hour expert session for $400, refunded in full if the expert can't answer your questions or give clear solutions. ZeroBounce offers a free consultation and says audit prices depend on the job. dmarcian sells consultation time in prepaid four-hour blocks, with no price on the page.
Try the free escalation routes first. Google's Report delivery issue form in Postmaster Tools is open to verified owners whose domain meets the sender guidelines, for messages that are DKIM and SPF authenticated with a matching From domain. For urgent problems sending to Outlook.com, the SNDS site says to contact Microsoft's sender support. Our cold email spam fix list covers the common fixes to try before anyone is paid.
If you do hire someone, send this before the first call so the hour goes on diagnosis:
Frequently asked questions
What is the best email deliverability tool?
There isn't one tool for every job. Provider dashboards, placement tests, DMARC reports and list verification each answer a different question. A small team sending from Google Workspace can cover most of it with Postmaster Tools, a free placement or setup test and a free DMARC digest, then pay for whichever job the free tools leave unanswered.
Is Google Postmaster Tools free?
Google's setup pages list no fee. You need a Google or Google Workspace account and a DNS record to verify your sending domain. Its dashboards only cover mail sent to personal Gmail accounts, and Google says data may be missing on days when your sending volume is low, so a founder sending a few dozen emails a day may see little.
How much does an email deliverability consultant cost?
GlockApps lists one: on 4 November 2026 its consulting FAQ offered a free 20-minute assessment and a 1-hour expert session for $400. ZeroBounce offers a free consultation and prices audits per job, dmarcian sells prepaid four-hour blocks without a listed price, and MxToolbox asks you to get in touch. Ask for a fixed fee for a defined job, such as an authentication audit, and send your headers and records in advance so the paid time goes on diagnosis.
Do I need a DMARC monitoring tool?
If you send about 5,000 or more emails a day to Gmail, Google requires a DMARC record, and reports are how you see which services pass. Below that it's still useful whenever several tools send as your domain. Google's own FAQ points to third-party DMARC tools for the details, and Postmark offers a free weekly digest.
What is Microsoft SNDS and do I need it?
SNDS is Outlook.com's data service for people who own sending IP ranges; its pages list no price. It shows volume, filter results and complaints per IP, and data may be missing for IPs sending fewer than 100 messages a day. If your mail goes out through Google Workspace or Microsoft 365, you don't own those IPs, so in our reading it's rarely useful.
Sources
- Gmail Help: Set up Postmaster Tools (checked 4 Nov 2026)
- Gmail Help: Postmaster Tools dashboards (checked 4 Nov 2026)
- Gmail Help: Sender requirements & Postmaster Tools FAQ (checked 4 Nov 2026)
- Gmail Help: Deprecation of the old Postmaster Tools interface (checked 4 Nov 2026)
- Gmail Help: Report delivery issues in Postmaster Tools (checked 4 Nov 2026)
- Google Workspace Admin Help: Email sender guidelines (checked 4 Nov 2026)
- Microsoft SNDS: FAQ (checked 4 Nov 2026)
- Microsoft SNDS: Welcome page (announcement dated 22 Sep 2026, checked 4 Nov 2026)
- Outlook.com Postmaster: Announcements (checked 4 Nov 2026)
- Yahoo Sender Hub (checked 4 Nov 2026)
- Yahoo Sender Hub: FAQs (checked 4 Nov 2026)
- mail-tester.com: Pricing and account features (checked 4 Nov 2026)
- GlockApps: Pricing (monthly) (checked 4 Nov 2026)
- GlockApps: Pricing (annual) (checked 4 Nov 2026)
- GlockApps: Email deliverability consulting (checked 4 Nov 2026)
- MxToolbox: Product pricing (checked 4 Nov 2026)
- Postmark: DMARC monitoring (checked 4 Nov 2026)
- dmarcian: Pricing (checked 4 Nov 2026)
- EasyDMARC: Pricing (checked 4 Nov 2026)
- ZeroBounce: Email validation pricing (checked 4 Nov 2026)
- Validity: Pricing and packaging (checked 4 Nov 2026)
- Validity: Everest (now opens Validity Engage) (checked 4 Nov 2026)
- ZeroBounce: Email deliverability consulting (checked 4 Nov 2026)
- dmarcian: DMARC Consultation (checked 4 Nov 2026)