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How do you test email deliverability without buying a platform? Testing email deliverability starts with free checks: confirm your domain's SPF, DKIM and DMARC records, send a real message to a scoring tool, and watch Google's own data on how Gmail treats your mail. Paid placement tools earn their cost only when email is how you sell, or when a problem keeps coming back after the basics are fixed.
Most companies find out about a deliverability problem secondhand. A client says the invoice never arrived, or a proposal turns up in someone's junk folder a week late, and by then the cause has usually been sitting there for months. A short testing routine catches it sooner, and most of that routine costs nothing.
What testing email deliverability measures
People lump different questions together under one word. The first is whether your domain is set up correctly: SPF, DKIM and DMARC records tell receiving servers that mail claiming to be from you really is. When those fail, nothing else matters much, and our guide to DMARC failure covers the fixes.
The second question is whether one message looks trustworthy, judged on its headers, links, content and authentication. The third is where your mail lands over time across Gmail, Outlook and Yahoo: inbox, spam or somewhere in between. Free tools answer the first two well. Paid tools exist mostly for the third.
The tools at a glance
| Tool | What it tests | Cost | Watch for |
|---|---|---|---|
| Google Postmaster Tools | How Gmail rates your domain: spam rate, reputation, authentication | No fee listed; needs a Google account and a DNS record | Gmail only, and data can be missing on low-volume days |
| Mail-Tester | One message you send to a test address | Free for occasional tests; extra test packs priced from 1 to 10 euros | One message is a snapshot, not a trend |
| MxToolbox Email Health Check | DNS, mail server and more than 100 blacklists | One free check every 24 hours; monitoring is paid | Checks setup, not where mail lands |
| InboxAlly | Inbox or spam placement, plus seed-based warmup | Free placement tester; Starter at $149 a month, Plus at $645 a month | Paid plans are built for senders repairing a damaged reputation |
| Instantly Inbox Placement | Placement tests for cold outbound | Add-on at $47 a month for one-time tests, $97 with automated tests | Sold alongside a cold email platform you may not need |
Prices are as published on each vendor's own pages; InboxAlly's figures come from its own comparison page. How we are compensated on some of these links is noted at the top of the page. We are not compensated for Postmaster Tools, Mail-Tester or MxToolbox.
Start with the free checks
Your domain records
Before testing any message, make sure SPF, DKIM and DMARC are published and passing. Our free domain health checker reads those records and explains each one in plain terms. For the server side, MxToolbox's Email Health Check looks at your DNS and mail server and checks more than 100 blacklists, although free users get one check every 24 hours.
Google Postmaster Tools
Postmaster Tools is the closest you'll get to hearing from Gmail directly. You add your domain, prove you own it with a TXT or CNAME record, and then get dashboards for spam rate, domain and IP reputation, authentication, encryption, delivery errors and compliance with Google's sender requirements. Google's sender guidelines advise keeping the user-reported spam rate below 0.1% and never letting it reach 0.3%.
Where it falls short: it says nothing about Outlook or Yahoo, and Google warns that data might be missing when a day's volume is too low. A 20-person firm sending ordinary business email may see gaps for that reason. It's still worth the ten minutes to set up, because when the numbers do appear, they come from Gmail itself.
Mail-Tester
Mail-Tester gives you a one-time address. You send a real message to it from the system you want to check, and it reports on authentication and content. Occasional use is free, and extra tests are sold in packs priced from 1 to 10 euros. Its limit is the obvious one: it reads a single message once, so it can't tell you that Outlook has been quietly filing your invoices as junk for a month.
When a paid tool is worth it
Paying for placement testing makes sense in a few situations. Email may be a revenue channel for you, through a newsletter or outbound prospecting. You may have just moved to a new sending platform or domain. Or a problem keeps returning even though your records pass.
InboxAlly
InboxAlly's free Email Placement Tester shows whether a message lands in the inbox or in spam, which makes it a sensible next step after Mail-Tester. Its paid service is seed-based warmup and reputation repair. InboxAlly publishes Starter at $149 a month for one sender profile and 100 seeds a day, extra profiles at $35 a month each, and Plus at $645 a month for five profiles. There is a 10-day trial with no card required and no annual contract. InboxAlly says it supports Gmail, Google Workspace, Yahoo, Hotmail and Outlook.
Choose it if your domain's reputation is already damaged and you need to rebuild it. Look elsewhere if you only send day-to-day business email; the free tester covers that, and the paid plans are priced for senders with a volume problem.
Instantly
Instantly is a cold email platform, and its placement testing is a separate add-on. The add-on costs $47 a month for unlimited one-time tests, or $97 a month to add automated tests. The outreach plans themselves start at $47 a month for Growth, which includes 5,000 emails and 1,000 uploaded contacts, and warmup comes with every plan.
Choose it if your team already runs outbound in Instantly and wants placement data in the same place. Look elsewhere if you don't send cold email at all. Buying a prospecting platform to test ordinary business mail is the wrong way around. If you are weighing outreach software anyway, our guide to prospecting tools for small B2B sales teams compares the options.
A testing routine for a small business
- Run a domain check monthly, and again after any change to your email provider, website host or marketing tools.
- Send one test message from every system that sends as your domain. That means your mailboxes, plus the CRM, newsletter tool, invoicing system and website forms.
- Set up Postmaster Tools once and look at the spam rate when you do the monthly check.
- Run a placement test before a large send or after moving platforms.
- Write down who owns your DNS. When someone adds a new sending tool and nobody updates SPF, mail from that tool starts failing, and the person who could fix it often doesn't know.
Deliverability is usually a symptom of how the domain is managed, not a mystery. For the infrastructure side, see email authentication and infrastructure.
Questions, answered plainly
How often should a small business test email deliverability? Check your domain records once a month and after any change to your email provider, website host or marketing tools. Send a message test whenever a new system starts sending as your domain, and run a placement test before any large send.
Is Google Postmaster Tools enough on its own? No. It only reports on mail sent to Gmail, and Google warns that data can be missing on days when your volume is low. Pair it with a domain check and an occasional message test.
What spam rate is too high? Google advises senders to keep the user-reported spam rate below 0.1% and to keep it from reaching 0.3% or higher. Bulk senders above 0.3% lose eligibility for Google's mitigation until the rate stays below 0.3% for seven consecutive days.
Do we need a paid deliverability tool? Most companies that send ordinary business email do not. A paid tool earns its cost when email is a sales channel, when you have moved sending platforms or domains, or when a problem keeps coming back after the records are fixed.
