Email deliverability tools

30 free checks, generators, tests and utilities for the domains and inboxes you send cold email from. Paste a domain and Ken grades its SPF, DKIM, DMARC, MX and eight more checks first. No signup, and nothing is sent from your domain.

Opens the Domain health check, then every check and generator it links to keeps your domain.

Check

9 tools

DNS and reputation

Generate

4 tools

Records to paste

Test

5 tools

A real message or report

Set up

4 tools

Fleet size and new domains

Utilities

8 tools

IP, ASN, SSL and more

Check

9 tools. One domain in, a verdict and the record to paste out. Nothing is sent.

Domain health check

SPF, DKIM, DMARC, MX and eight more checks on one domain, graded A to F with the exact records to paste. Free, no signup, and nothing is sent from your domain.

SPF checker

See every include in your SPF record, count the DNS lookups against the limit of 10, and get a fixed record to paste.

DKIM checker

Sweeps the common DKIM selectors on your domain, shows every key it finds and flags keys shorter than 2048 bits.

DMARC checker

Reads your DMARC record tag by tag, shows where you sit on the none, quarantine, reject ladder and gives you the record for the next step.

BIMI checker

Checks your BIMI record, validates the logo against SVG Tiny PS and shows whether Gmail, Apple Mail and Yahoo would display it.

MTA-STS checker

Fetches your MTA-STS policy, compares it with your live MX hosts and gives you the record and policy file to publish.

TLS-RPT checker

Checks whether your domain publishes a TLS-RPT record, so servers that deliver mail to you can report when TLS to your mail servers fails.

Blacklist checker

Checks a domain, its mail server and website IPs, or one IPv4 against public email blocklists, and links to the delisting page for every listing.

DNS lookup

Looks up A, AAAA, MX, TXT, CNAME, NS, SOA and PTR records, and asks four public resolvers for one record type to show whether they agree.

Generate

4 tools. Build the SPF, DMARC and DKIM records your domain needs, or flatten an SPF record that runs past 10 lookups.

SPF record generator

Pick the services that send email for you and get one SPF record that stays under the 10-lookup limit.

SPF flattener

Replaces the includes in your SPF record with the IP ranges behind them, so a record over 10 lookups passes again.

DMARC record generator

Pick a policy, test mode and where reports go, and get the DMARC record for your next step from none to reject.

DKIM key generator

Creates a 2048-bit DKIM key pair in your browser and gives you the DNS record to publish. The private key never leaves your device.

Test

5 tools. Send a test email, paste headers or drop a DMARC report. Ken reads the result.

Mail tester

Send one email to a test address and get a 10-point score for authentication, spam filters, blacklists, content and links.

Email header analyzer

Paste the headers of any email to see each hop and its delay, the SPF, DKIM, DMARC and ARC results, and the spam scores.

DMARC report analyzer

Drop a DMARC aggregate report (XML, gz or zip) and see who sends email as your domain and which sources fail.

SMTP test

Connects to your mail server and checks the greeting, EHLO, STARTTLS, the TLS certificate and reverse DNS, with the time each step took.

Inbox placement test

See whether your cold email lands in the inbox, a tab or spam at Google Workspace, Gmail, Microsoft 365 and Outlook.com. The test runs in the Ken app, on your own campaign.

Set up

4 tools. Size the fleet and set it up right before the first send.

Cold email inbox calculator

Enter how many emails you want to send a month and get the inboxes, domains, warmup time and cost you need.

Email warmup calculator

Get a day-by-day warmup ramp for a new inbox, from the first sends to your target daily volume.

Sending domain generator

Enter your brand and get sibling domains for cold email that are free to register now, so outreach never runs on your main domain.

Email signature generator

Build an HTML signature or a plain-text one for cold email, with a live Gmail and Outlook preview and install steps.

Utilities

8 tools. Small network tools. Fast, with no result to email.

What's my IP ASN lookup CIDR calculator RDAP domain lookup SSL certificate checker llms.txt checker AI crawler checker Password generator

Ken runs these checks on every inbox it sends from.

Connect your domains and Ken watches DNS, blacklists and bounce rates daily, and pauses an inbox before it does damage.

Start free - 1,000 credits, no card

What the deliverability suite covers

Cold email lands or it does not, and most of what decides that is set before the first send: DNS records, the reputation of the domain and its IPs, and how many messages each inbox sends per day. These tools cover that whole path. They are the same checks Ken runs on every connected inbox, opened up for any domain.

Check a domain

The domain health check runs SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT, BIMI and reverse DNS in one lookup, flags a domain that also carries your website and team mail, and grades the result A to F. Each single-check page goes deeper on one record: the SPF checker draws the include tree and counts the 10 DNS lookups, the DKIM checker sweeps the common selectors, the DMARC checker walks the policy ladder from none to reject. Every warning comes with the exact record to paste.

Test a real message

DNS can be right and mail can still go to spam. The mail tester gives you an address to send one real email to and scores what arrives out of 10. The header analyzer reads the hops and authentication results from a message you already have. The DMARC report analyzer turns the XML reports nobody opens into a list of who sends as you.

Set up the fleet

The inbox calculator turns a monthly volume into inboxes, domains and a cost, the warmup calculator into a day-by-day ramp. The sending domain generator finds sibling domains that are free, so cold email never runs on the domain your customers write to.

Questions

Where should I start?

Run the domain health check on your sending domain. It grades SPF, DKIM, DMARC, MX and eight more checks, and links to the single-check tool for anything that needs a fix.

Do these tools send anything from my domain?

No. The checks read public DNS and the mail servers a domain points to. Nothing is stored beyond a 10-minute cache unless you email yourself the report.

Can I run them on a prospect's domain?

Yes. Everything here reads public records, so a prospect's domain works the same as yours. Agencies use the health check as a first-call opener and email the report to the prospect from the form under the result.

Can I keep a result?

Yes. The form under a check's result emails you the full report with the records to paste, and a saved link that stays live for 90 days. The DKIM key generator saves nothing, because a private key should never leave your device.

Is there an API?

Yes. The checks are also a free JSON API, documented at /tools/api. Most calls need no key, and a free Ken API key raises the limits.

Other suites

67 free tools in 6 suites.

Copy lab

8 tools. Paste an email and the checks run on it at once.

Prospecting

5 tools. From a website to an ICP, a market count and a checked list.

CSV tools

14 tools. Clean, combine and prepare a list in your browser.

Planner

10 tools. Calculators that open on a worked example.

All 67 free tools