Webhooks, Clay, Zapier, Instantly, Smartlead, HeyReach

All of these accept a JSON POST. Paste the catch-hook URL in Integrations. Payloads are flat (first_name, email, email_grade, company_domain, intent_score, last_pages, profile_url, …). Set a signing secret and verify X-Deanonymized-Signature = HMAC-SHA256(secret, timestamp + "." + body). URLs must be public https; private addresses are rejected.