EMAIL AUTHENTICATION

SPF, DKIM & DMARC tools

Check a domain's email authentication, then generate the exact DNS records you need — SPF, DMARC and a fresh DKIM key. Everything runs in your browser; nothing is uploaded.

Checker DMARC generator SPF generator DKIM key generator

SPF, DKIM & DMARC checker

Enter a domain to look up its live DNS records and see what's protecting (or missing from) its email.

Domain

Leave the selector blank to probe common ones: google, default, selector1, resend, cf2024-1, k1.

DMARC record generator

Build a valid _dmarc TXT record. Start at p=none to monitor, then tighten to quarantine or reject.

Your domain

Policy (p)

Subdomain policy (sp)

Aggregate report address (rua)

Percentage (pct)

SPF alignment (aspf)

DKIM alignment (adkim)

SPF record generator & validator

Tick the senders you use to build one SPF record — or paste an existing record to validate it against the 10-lookup limit.

BUILD A RECORD

Google Workspace / Gmailinclude:_spf.google.com Microsoft 365 / Outlookinclude:spf.protection.outlook.com Cloudflare Emailinclude:_spf.mx.cloudflare.net Resend / Amazon SESinclude:amazonses.com Mailchimpinclude:servers.mcsv.net Add your own (space-separated — e.g. ip4:198.51.100.5 include:mail.yourhost.com)

Policy for everything else

VALIDATE AN EXISTING RECORD

Paste an SPF record

DKIM key generator

Generate a fresh RSA-2048 keypair, right here in your browser. Paste the private key into your mail system and publish the public key in DNS.

Selector

Domain (for the record name)

Keys are generated locally with your browser's WebCrypto engine. Nothing is sent anywhere — if you reload this page, the key is gone, so copy it before you leave.

Tired of wrangling DNS for every domain? Blue Folder Mail gives you encrypted mailboxes on every domain you own, with SPF, DKIM and DMARC configured for you. See plans →