9 Tools to Check Email Deliverability and DMARC (Free and Paid)
The tools I use and recommend, what each one is good for, and what it cannot tell you.
By Naomi, Klaviyo-certified, Signify Studio
The short answer: Start with Gmail's Show original to see whether one real email passes SPF, DKIM and DMARC, then use Google Postmaster Tools to watch your Gmail reputation over time, and a DMARC reporting tool to see who sends email as your domain. A few free tools cover most of what a DTC brand needs.
Disclosure: Signify Studio makes one of the tools on this list, the free scan. It is listed in its own place and is not ranked above the others. The rest are independent tools we do not have a commercial relationship with.
How to choose
- I want a quick check of one email: Gmail Show original or Mail-Tester.
- I want to see my sender reputation: Google Postmaster Tools.
- I want to see who sends as my domain: a DMARC reporting tool.
- I want to look up my DNS records: MXToolbox.
The tools
1. Gmail Show original
Free, built inOpen any email you received in Gmail, choose Show original, and Gmail lists whether SPF, DKIM and DMARC passed. It is the fastest way to check one real message from your Klaviyo account. It only tells you about that one email.
2. Google Postmaster Tools
FreeShows how Gmail sees your domain: spam rate, domain reputation and authentication results. You verify your sending domain, and Gmail needs enough daily volume from you before data appears. It is the best free view of your standing with Gmail, but it covers Gmail only.
3. MXToolbox
Free tools, paid monitoringLook up your SPF, DKIM, DMARC and MX records, and check whether your domain or sending IP is on a blocklist. Good for confirming a DNS change worked. It reads records; it does not tell you whether mailbox providers trust you.
4. Mail-Tester
Free for limited testsYou send a test email to a temporary address and get a score with a breakdown of authentication and content issues. Handy before a big send. A good score on one test does not guarantee inbox placement.
5. Postmark DMARC Digests
FreeCollects your DMARC reports and sends a plain weekly summary of who is sending email as your domain. A simple way to start reading DMARC reports without learning the raw format.
6. dmarcian
Paid, with some free toolsA fuller DMARC reporting and management service. Useful when you have many sending sources and want to move safely from p=none to enforcement. It is more than a small brand with one sender needs.
7. Klaviyo's own deliverability reporting
Included with KlaviyoYour campaign and flow analytics show bounce, spam complaint and unsubscribe rates, and Klaviyo's settings walk you through setting up a dedicated sending domain. Check these first. They cover your Klaviyo sends only, not other tools that email as your domain.
8. Microsoft SNDS
FreeShows reputation data for sending IPs to Outlook and Hotmail. It is most useful when you control your own sending IPs. If your email platform sends from shared IPs, other tools on this list tell you more.
9. Signify Studio free scan
Free (made by us)Checks your sending setup in about ten seconds and shows what to fix first. It is a starting point, not a replacement for the tools above. Run the scan.
Found a problem? The deliverability fix covers DNS, DMARC, DKIM, SPF and reputation, and it is part of the Flow Bundle.
What no tool can tell you
No tool shows exactly where your email lands in every inbox. Combine signals: authentication passing, a healthy Postmaster reputation, low spam complaints, and steady opens and clicks over time. For why this matters, see email revenue dropped but send volume stayed flat and why Klaviyo emails go to spam.
Questions people ask me
What is the best free tool to check email deliverability?
Google Postmaster Tools is the best free view of your reputation with Gmail, and Gmail's Show original is the fastest check of one email. Use both.
How do I check if my DMARC is set up correctly?
Look up your DMARC record with a DNS lookup tool such as MXToolbox, then use a DMARC reporting service to confirm legitimate senders are passing.
Do I need a paid deliverability tool?
Most small DTC brands do not. Free tools cover authentication and Gmail reputation. Paid tools help when you have many sending sources or need to enforce DMARC.
Start with the free scan.
Then decide what to fix first.