Free email deliverability tools: find what's hurting your inbox placement
No code. Paste a domain or email and get a clear answer in seconds.
Email deliverability tools check what mailbox providers look at before they accept your mail: SPF, DKIM and DMARC authentication, MX and reverse DNS, blocklist listings and the bulk sender rules Gmail, Yahoo and Microsoft publish. Each check here is a DNS lookup or runs in your browser, so nothing is sent from your domain.
Since February 2024 Gmail and Yahoo require bulk senders to authenticate with SPF and DKIM, publish DMARC and keep spam complaints low; Microsoft followed for Outlook.com in May 2025. The bulk sender checker tests a domain against all of it at once; the pages below cover each record on its own.
If you are fixing a problem rather than auditing, start from the evidence: paste the headers of a message that landed in spam, or decode the bounce you got back.
69 email deliverability tools
Catch-all checker
Test whether a domain accepts mail for every address by probing a random address that cannot exist.
Email header analyzer
Paste raw headers to see SPF, DKIM and DMARC results, alignment, every hop with its delay, and spam verdicts.
Deliverability audit
Audit a domain's MX, SPF, DKIM, DMARC and blocklist status in one pass, with what each result means.
SPF record generator
Build a valid SPF TXT record from the services that send for your domain, with a live count against the 10-lookup limit.
DMARC record generator
Build a DMARC TXT record with the right policy and reporting address, and see plainly when p=none enforces nothing.
MX record lookup
Free MX lookup: check the MX records for any domain and see which mail servers accept its email, in priority order, and which provider runs them.
SPF record checker
Free SPF record checker: look up a domain's SPF TXT record, see the raw value, and catch missing records, duplicate records and soft-fail policies.
DMARC record checker
Check any domain's DMARC record: see the raw TXT at _dmarc, the policy (none, quarantine or reject) and what it actually enforces. Free DMARC lookup.
DKIM checker
Check DKIM records on any domain, no selector needed: auto-detects common selectors, decodes key length and flags weak, revoked or broken keys. Free.
Email blacklist check
Free email blacklist check: see if your domain is listed on Spamhaus DBL, SURBL or SpamCop, with refused queries shown as unchecked, not as a false alarm.
Gmail & Yahoo bulk sender checker
One domain in, a checklist out: SPF, DKIM, DMARC, PTR and MX from live DNS, plus one-click unsubscribe, alignment and spam rate as manual items.
Reverse DNS lookup
Enter an IPv4 or IPv6 address to get its PTR hostname, plus the forward-confirm check that Gmail and Yahoo require on sending IPs.
Email provider lookup
Enter a domain or address and see its mail provider and any security gateway (Proofpoint, Mimecast, Barracuda), read from MX and SPF records.
Bounce message analyzer
Paste an Undeliverable or Delivery Status Notification email and get the code, hard or soft, the likely cause and the fix. Runs in your browser.
Spam words checker
Paste email copy to see which phrases match published SpamAssassin rules or break Google's sender guidelines, and which flags are only common advice. Runs in your browser.
Subject line tester
Preview a subject line and preheader in Apple Mail, the Gmail app and Gmail on desktop, and check it against published filter rules and Google's guidelines.
IP blacklist check
Check an IPv4 address against Spamhaus ZEN, Barracuda, SpamCop, PSBL and Mailspike, with each listing code explained and unreachable lists reported honestly.
BIMI checker
Check a domain's BIMI record, SVG Tiny PS logo, VMC or CMC certificate and DMARC policy against Google's and the BIMI Group's published requirements.
Domain age checker
Registration date, age, expiry and registrar for up to 10 domains, read from each registry's RDAP server, with honest gaps where a registry publishes nothing.
DKIM key generator
Create a 2048-bit DKIM key pair and the selector._domainkey TXT record in your browser. The private key never leaves the page.
Microsoft sender requirements checker
Check SPF, DKIM and DMARC against Microsoft's high-volume sender requirements for Outlook.com, Hotmail and Live, with its recommendations listed separately.
Bulk MX / provider lookup
Upload a CSV of emails or domains, get each row's mail provider from MX and SPF, and download the list split into Google, Microsoft and other.
List-Unsubscribe header generator
Builds the two one-click unsubscribe headers from your URL, and checks pasted headers for HTTPS, the exact Post value, a recipient token and DKIM coverage.
DNS lookup
A, AAAA, CNAME, MX, NS, TXT, SOA and CAA in one lookup, with the email records (MX, SPF, DMARC) summarised and linked to the in-depth checkers.
TXT record lookup
Shows TXT records on the domain and on _dmarc, default._bimi, _mta-sts and _smtp._tls, labels SPF, DKIM, DMARC and verification tokens, and flags duplicates.
DMARC report analyzer
Turns rua XML attachments from Google, Microsoft and Yahoo into a table of sending IPs, pass rates and unaligned senders. Unzipped in your browser.
Cold email template generator
Fill in your offer once and get three drafts (trigger-led, quick question, problem-agitate-solve and more) with subject lines. Templates, not AI.
Spintax checker
Checks {a|b} and {{RANDOM | a | b}} syntax with line and column for every error, counts the variations and shows random renders. Merge fields are left alone.
CNAME lookup
Follows the CNAME chain, checks the target against Instantly, Smartlead or lemlist, catches the doubled-domain and proxied-record mistakes, and tests HTTPS.
WHOIS lookup
Registrar, creation and expiry dates, EPP status, name servers and DNSSEC from the registry's own RDAP server, with contact records hidden until you ask.
HTML to plain text email converter
Paste HTML email source and get a readable text/plain alternative: headings, lists and links kept, pixels and hidden preheaders dropped, lines wrapped at 78.
SPF lookup counter
Expands every include and redirect, counts DNS lookups and void lookups against RFC 7208's limits, and shows which include uses the most.
DKIM signature validator
Paste a raw message to recompute the body hash and check the signature against the published key, with the reason when it fails.
Cold email subject line generator
Turns your topic, outcome and trigger into five styles of subject line, each checked against spam-filter rules and phone width.
BIMI record generator
Build the BIMI TXT record from your logo and certificate URLs, get the host name to publish it at, and check DMARC is at enforcement first.
Email size checker
Measures the HTML in KB against Gmail's roughly 102 KB clipping point, breaks down what makes it heavy, and gives you a minified copy.
MTA-STS checker
Reads the _mta-sts and TLS-RPT records, fetches the policy file over HTTPS the way a sending server does, and checks every MX host against it.
SMTP settings lookup
Detects who hosts a domain's mail from its MX records and shows that provider's SMTP, IMAP and POP settings, each from the provider's own docs.
Inbox preview: subject and preview text
Simulated Gmail, Outlook and iPhone inbox rows show where the subject and preheader get cut, and what an email's HTML puts in the preview.
Email signature generator
Fill in your details, pick a layout and colour, and copy a table-based HTML signature that pastes cleanly into Gmail, Outlook and Apple Mail.
DNS propagation checker
Asks 12 public DNS-over-HTTPS resolvers and the zone's own name server for one record, shows each answer as it came back, and how long each cache keeps an old one.
SPF flattener
Resolves every include, a and mx in an SPF record to the ip4 and ip6 ranges behind them, outputs the flattened record (split into sub-records when it's too long) and warns that it goes stale.
MX records generator
Pick Google Workspace, Microsoft 365, Zoho, Fastmail or iCloud+ and a DNS host; get the MX, SPF, DKIM and DMARC records from the provider's own guide, ready to paste.
Mailto link generator
Type the address, subject and message and copy a mailto: link that opens a ready-to-send draft, as a plain link, HTML or Markdown. Spaces and line breaks are encoded the way RFC 6068 asks.
TLS-RPT record checker
Enter a domain to read its _smtp._tls TXT record, validate it against RFC 8460 (case-sensitive tags, one record only) and check that every mailto: or https: destination can receive reports.
BIMI SVG validator and converter
Paste or upload an SVG to check it against the SVG Tiny PS profile and Gmail's requirements, then download a converted copy with before and after previews. Runs in your browser.
Bulk domain availability checker
Paste up to 100 domains (500 when signed in), or bare names to try across .com, .io and other TLDs, and see which are registered and which look available, straight from each registry's RDAP server.
Bulk SPF, DKIM and DMARC checker
Paste a list of domains and see, for each one, whether SPF, DKIM, DMARC and MX are published, with a pass, warn or fail and the reason in plain English.
Bulk DNS lookup
Paste a list of domains or host names and get their A, AAAA, MX, TXT, NS and CNAME records side by side, in one table and one CSV.
Bulk website status and parked domain checker
Paste a list of domains and see each one's HTTP status, where it redirects, and whether it looks parked or for sale, with the signal that says so.
Company name to domain finder
Paste company names and get the likely domain for each, with high, medium or low confidence and the reason, from Wikidata and a check of the home page.
Domain to company name lookup
Paste domains or work email addresses and get the company or site name for each, with high, medium or low confidence, the source and the mail server.
Email spoofing test
Enter a domain, or a list, and get a plain yes, partly or no from its DMARC and SPF records, with what to change to stop forged mail.
DKIM selector finder
Enter a domain and see which of about 80 known DKIM selectors it publishes, with each key's length and the sending platform where DNS shows it.
Bulk catch-all checker
Paste domains or email addresses and see, for each domain, whether its mail server accepts a made-up address: catch-all, not catch-all or unknown, with the reason.
Email stack lookup
Paste company domains and see each one's mailbox provider, sending platforms, security gateway, DMARC reporting and verified SaaS, with the DNS record behind each.
Domain drop date calculator
Enter a domain or a list. Each one's registry status and expiry date give its phase and the window in which it could be deleted and released.
Bulk nameserver lookup
Paste domains and get each one's NS records with the company that runs them (Cloudflare, Route 53, GoDaddy, Namecheap and about 40 others), plus parked domains, in one table.
Which ESP sent this email?
Paste the raw headers of any email and see the platform that sent it, such as SendGrid, Mailchimp or Amazon SES, with the DKIM, bounce and Received lines behind it.
Cold email domain generator
Enter your brand or domain, pick prefixes, suffixes and TLDs, and get sending-domain ideas like getacme.com and acmehq.com, each checked against the registry for likely availability.
Lookalike domain checker
Enter your domain to generate up to 150 typo, homoglyph, Unicode and TLD variants and see which are registered, which answer on the web and which have MX records to send or receive email.
MTA-STS generator
Enter your domain, pull in your MX hosts and pick a mode to get the mta-sts.txt policy file, the _mta-sts TXT record and a matching TLS-RPT record, checked against RFC 8461.
Is Gmail down?
Reads Google's own status feed for open Gmail incidents and connects to Gmail's mail servers to read their greeting, with the time of each check. Outlook.com too, from Microsoft's status page.
UTM builder
Paste a URL, pick an email or SMS preset and get a tagged link that GA4 counts in the right channel. Tag hundreds of URLs at once and download them as a CSV.
EML viewer
Drop an .eml file to read it: sender, recipients, date, the HTML and text versions, attachments to download and the raw headers. Remote images stay blocked until you allow them.
Bulk domain age checker
Paste or upload a list of domains or emails and get each domain's creation date, age and registrar from RDAP, sorted, filtered by age and downloadable.
Bulk domain expiry checker
Paste or upload a list of domains and get each one's expiry date, days left and registrar from RDAP, grouped into expired or in grace, under 30 days, 30–90 days and 90+ days.
Available domain name generator
Enter up to three keywords and pick TLDs: name ideas from prefixes, suffixes and keyword joins are checked against each registry's RDAP server and DNS, likely-available first.
Bulk WHOIS lookup
Paste or upload domains and get registrar, created, updated and expiry dates, EPP status codes, nameservers and DNSSEC for each, from the registry's RDAP server, in one table.