SPF, DKIM & DMARC for Proton Mail
Proton Mail doesn't host your domain's DNS — add these wherever your domain is registered or its DNS is managed.
SPF & DKIM — get both from your domain's settings in Proton
In Proton: Settings → Go to settings → Domain names (select your custom domain). Proton shows you the exact SPF and DKIM records to publish, including rotating DKIM selectors (commonly protonmail, protonmail2, protonmail3). Copy those exactly as shown rather than from a guide — the DKIM values are unique to your account and Proton signs your mail with its own key, not one you generate yourself. A key pair from our generator would never actually get used to sign anything.
DMARC
Not specific to Proton Mail — the same record works everywhere. Use the DMARC record generator to build yours.
Once it's live, check your setup free to confirm everything reads correctly.