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Free DKIM generator

Generate the keys.
Keep signing in your control.

Generate a free RSA DKIM key pair and a public DNS TXT record locally in your browser. Download the signing key and zone record without an account or upload.

Keys are generated by your browser’s Web Crypto API. No keys, domain, or selector are uploaded or saved by Reply Runway. Save the private key before clearing, leaving, or generating again.

Public record. Private signing key.

Generate a matching RSA key pair and a DKIM TXT record. Publish only the public record. Install the private key on a signing system you control.

Publish the record. Keep the key private.

Confirm your signing system

Use this generator only if your sending system accepts imported RSA private keys. Hosted email providers usually supply their own DKIM records.

Save the matching key pair

Download the private key for the signing server and keep it protected. The public TXT record goes in DNS at the selector’s hostname.

Enable signing and verify

Configure the signing system to use the same selector and domain. After publishing, use the DKIM lookup and check a real message’s authentication result.

Is DKIM key generation free?

Yes. It runs locally in your browser using Web Crypto, with no account, payment, or upload.

Does adding the TXT record enable DKIM automatically?

No. Your mail system must sign messages with the matching private key, domain, and selector. Publishing a record alone does not sign mail.

What if my provider gives me a CNAME instead?

Use the provider’s exact instructions. Do not replace a managed DKIM record with a generated key that the provider cannot import.

Domain and email setup guides DKIM cryptographic requirements

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