Developer tools
Free email tools
Check email DNS, inspect headers, and test signatures. No account required.
SPF checker
Look up the SPF TXT record currently published by a domain.
Open →DKIM checker
Look up the DKIM public key for a domain and selector.
Open →DMARC checker
Look up a domain's DMARC policy and report address.
Open →Email header analyzer
Read authentication and routing details from pasted email headers.
Open →Webhook signature tester
Generate or verify a zaSend HMAC-SHA256 webhook signature.
Open →Email authentication
SPF, DKIM, and DMARC checks read the records currently visible in public DNS through Cloudflare 1.1.1.1.
Private debugging
Pasted headers, payloads, and webhook secrets are processed for the request and are not saved to your zaSend account.