Free cold email tools
Tools we use when we set up cold email for customers. They run in your browser, need no sign-up and store nothing.
Check your domain
Records, blocklists and reputation of a domain you send from
- Domain health checkerBlocklist lookups for the domain and its mail server IPs, SPF, DKIM, DMARC and MX records, and registration and expiry dates, with what to fix for each findingUse it when placement drops, before you send from a domain you bought, and once a month on every sending domainOpen the checker
- SPF, DKIM and DMARC checkerSPF record and its DNS lookup count, DMARC policy, DKIM keys at common selectors or the one you enter, and MX records, with what to fix for each findingUse it after you set up a new sending domain and after you add a service that sends email as that domainOpen the checker
- Email blacklist checkerA domain on 2 domain blocklists and an IP, or a domain's mail server IPs, on 11 IP blocklists, with reverse DNS, what each list means and its removal pageUse it when bounces mention a blocklist, when replies drop on one domain, and before you send from a domain or server you did not set upOpen the checker
- Domain reputation checkerBlocklists for the domain and its mail server IPs, SPF, DKIM, DMARC, MX and domain age, with links to Postmaster Tools, SNDS, Spamhaus, Talos and Safe BrowsingUse it when replies or placement drop on a domain, before you buy or reuse a domain, and to see what mailbox providers can see about yoursOpen the checker
- SPF checkerThe SPF record as a tree with every nested include, the DNS lookup count against the limit of 10, void lookups, repeated terms, +all, ?all and ptr, with the corrected record and a flattened variant when neededUse it when you add a sending service to a domain, when mail fails SPF with permerror, and before you send from a new domainOpen the checker
- DMARC checkerThe DMARC policy and subdomain policy, every tag in plain words, report addresses and their authorization, syntax errors and the Gmail and Yahoo requirement, with the corrected record and the next policy stepUse it when you set up a new domain, before you raise the policy from none to quarantine or reject, and when DMARC reports stop arrivingOpen the checker
- DKIM checkerDKIM keys at your selector and at the selectors providers document, who hosts each key, key type and length, revoked keys, testing mode and CNAMEs that point to nothing, with where to get a new keyUse it after you connect a mailbox provider or sending tool to a domain, when mail fails DKIM, and before you raise the DMARC policyOpen the checker
- MX lookupMX records by priority, the mail provider behind each host, IPv4 and IPv6 addresses of every host, null MX, hosts that do not resolve, IPs or CNAMEs used as MX, mixed providers and an SPF record that misses the providerUse it after you move a domain to a new mailbox provider, when replies or bounces do not arrive, and to see which provider a domain usesOpen the lookup
Generate records
SPF and DMARC records ready to paste at your DNS host
- SPF record generatorOne SPF record from the services you send from (Google Workspace, Microsoft 365, Zoho, SendGrid, Mailgun, Amazon SES, HubSpot, Brevo and more), your IPs and other includes, with a live DNS lookup countUse it when you add a sending service to a domain, set up a new domain, or merge two SPF records into oneOpen the generator
- DMARC record generatorA DMARC record for your stage (none, test, quarantine, reject) with report addresses, subdomain and non-existent subdomain policy, alignment, and the records a report domain must publishUse it when a domain has no DMARC record, when Gmail or Yahoo flag the domain, or when you are ready to move the policy up a stageOpen the generator
- SPF flattening toolDNS lookups per include across the whole SPF tree, multiple SPF records merged into one, and a flattened record with chained _spf records when the addresses do not fitUse it when a checker reports too many DNS lookups or SPF permerror, or when a domain has two SPF recordsOpen the flattener
- SPF, DKIM and DMARC by providerThe records for Microsoft 365, SendGrid, Amazon SES, Mailgun, HubSpot and more, and where they go at Cloudflare, GoDaddy, Namecheap and other DNS hosts, each with a pre-set checkOpen the setup guides
Analyze an email
Why a message landed in the inbox or in spam
Plan & cost
Mailboxes, domains and the monthly bill for your volume
- Cold email capacity calculatorSending mailboxes, spare mailboxes, domains, monthly cost and a warmup timeline for the monthly volume you enter, at 25 cold emails per mailbox a working day and up to 5 mailboxes per domainUse it before you buy domains, when you plan to raise volume, or to compare what your current setup costs with $2.50 a mailboxOpen the calculator
- Cold email cost calculatorMailboxes, domains, warmup time, new leads a month and the monthly cost of the same volume on Outreach2day and six stacks (Instantly, Smartlead, Google Workspace, Maildoso, Mailforge, Zapmail), with the formula and sourcesUse it to budget a new cold email setup, to price a volume increase, or to check what your current mailbox vendor and sequencer cost togetherOpen the calculator
Copy
Spam words, links and spintax before a sequence goes out
- Cold email copy checkerLinks, bare domains, images, spam-trigger phrases, fake Re: and Fwd: subjects, length and missing questions, with the reason behind each flagUse it on every email in a sequence before launch; in the first email, links count as errorsOpen the checker
- Spintax validatorUnbalanced braces, empty options, option spaces that get trimmed at send time, nested spintax and nested fallbacks in {{RANDOM|a|b}} or {a|b} format, with sample renders for filled and empty merge fieldsUse it before you paste a subject line or an email with spintax into your sequencerOpen the validator
Setup guides
SPF, DKIM and DMARC by provider
The exact records for the service you send with and the DNS host they go into, each with a check pre-set for that provider.
Free guide19 min read
Send 100,000 cold emails a month
Domains and mailboxes you need, DNS, warmup, lists, copy and follow-ups, with a launch checklist, sent to your inbox.
In your AI assistant
The same checks as agent skills
Download a SKILL.md and Claude, ChatGPT, Gemini, Grok or Cursor runs these checks on what you paste.
- Cold email copy reviewerCopy
- Cold email follow-up sequence plannerCopy
- Cold email link checkerCopy
- Merge variable render checkCopy
- Cold email opener writerCopy
- Cold email spintax linterCopy
- Cold email subject line spintax generatorCopy
- Email blacklist check for IPs and domainsDeliverability
- Bounce triage for cold emailDeliverability
- Burned sending domain detectorDeliverability
- Spam complaint rate guard for cold emailDeliverability
- SPF, DKIM and DMARC audit for sending domainsDeliverability
- Inbox placement test readerDeliverability
- Warmup metrics readerDeliverability
- Cold email capacity plannerInfrastructure
- Cold email sending domain plannerInfrastructure
- All cold email skills21 skills
Mailboxes, warmup and sending in one place
$2.50 a mailbox a month. DNS records are set for you, and every mailbox shows its warmup numbers from day one.