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DKIM by provider

DKIM record for Mailjet

Mailjet's DKIM record is a TXT record at mailjet._domainkey on your domain. Its value, starting with k=rsa; p=, is a public key Mailjet generates; you find it in your account under SPF/DKIM Authentication. New keys are 2048 bits by default, and you can regenerate the key as 1024, 2048 or 4096 bits once the whole domain is validated.

Record type
TXT
Selectors
mailjet
Private key held by
Provider (you publish its key)

The DNS records

The key below is shortened. Copy the full value from the SPF/DKIM Authentication section of your Mailjet account.

Mailjet DKIM key

Type: TXT · Host: mailjet._domainkey 

k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNAD…

Mailjet notes that some DNS hosts need the whole TXT value in double quotes.

Set it up and turn on signing

  1. Validate the sending domain in Mailjet first: on the Domains and Senders page in your account settings, click the cog next to the domain and choose Validate, then add the TXT record Mailjet shows.
  2. Open the SPF/DKIM Authentication section to see the DKIM host and value for the domain.
  3. At your DNS host, add a TXT record named mailjet._domainkey with that value. Check afterwards that the host didn't append your domain a second time.
  4. Back in Mailjet, open Account Settings > Domains & DNS and select the domain. A green check mark next to DKIM means the key was found.

DMARC alignment

Once the TXT record is live, Mailjet signs with your domain, so the DKIM result aligns with a From address at that domain and DMARC can pass on it. Mailjet presents SPF (include:spf.mailjet.com) and DKIM as a pair and recommends adding DMARC on top. It also says its support only gives guidelines for DMARC and doesn't analyze reports.

Key length and rotation

Mailjet's key lives in your zone, so a new key means a new TXT value. Use Regenerate Key under DKIM in the SPF/DKIM Authentication setup and choose 1024, 2048 (the default) or 4096 bits, then replace the DNS value. Existing domains aren't upgraded automatically. The button stays greyed out if only an address, not the domain, is validated.

Common mistakes

  • Picking 4096 bits at a host that can't store it. Mailjet warns some providers truncate long TXT values; regenerate a 1024-bit key if yours does.
  • Regenerating without updating DNS. The old value in your zone no longer matches the key Mailjet signs with.
  • Extra spaces in the value. Mailjet says the TXT record must match what it provides exactly.
  • Validating only a sender address. Key regeneration needs the whole domain validated.

Check your Mailjet DKIM key

The selector is filled in for you; add your domain. Free, reads public DNS only.

Frequently asked questions

What is Mailjet's DKIM selector?

mailjet. The record is a TXT record at mailjet._domainkey on your domain, holding the public key from the SPF/DKIM Authentication section of your Mailjet account.

How do I change the Mailjet DKIM key length?

Go to Account, Domains & Sender addresses, SPF/DKIM Authentication, and the setup page; click Regenerate Key under DKIM, choose 1024, 2048 or 4096 bits and confirm. Then replace the TXT value in your DNS with the new one.

Why is the Regenerate Key button greyed out in Mailjet?

Mailjet only lets you regenerate the DKIM key when the entire domain is validated. If you validated a single sender address at that domain, validate the domain itself first.

Sources

Checked against Mailjet's documentation on October 22, 2026. Providers change their setup screens; if yours differs, follow the values your admin console shows.

DKIM records for other providers

Compare every provider's selectors in one table · SPF record for Mailjet

Related guides

SPF, DKIM & DMARC

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