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Deterministic spam-SIGNAL score for the email content (caps ratio, image-to-text ratio, spam phrases, missing unsubscribe, raw-IP links…). HONEST: a content signal score, NOT an inbox-placement prediction; SpamAssassin/Rspamd sidecar = the calibrated upgrade (see docs). Pure local compute.
The full HTML of the email you are about to send (paste the source). Parsed read-only in a no-network, no-script sandbox.
Optional subject line — included in the spam-signal analysis.
Optional plain-text alternative of the email. If omitted, the audit flags the missing multipart/alternative text part.
curl -X POST https://api.reefapi.com/email-preflight/v1/spam_score \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"html":"<p>100% FREE!!! ACT NOW — WIN CASH PRIZE</p>","subject":"FREE MONEY"}'Hit Send to run this endpoint live.