What problem does it solve? Integrating identity verification and KYC into an application requires navigating dozens of Cashfree Secure ID endpoints, authentication schemes, webhook events, and SDK variants, and mistakes like using the wrong penny drop endpoint or skipping webhook signature verification cause real production failures. ## Core Features & Use Cases - Bank Account & Identity Verification: Covers penny drop (BAV sync/async/bulk), PAN, Aadhaar via DigiLocker, GSTIN, driving licence, passport, voter ID, and KYB checks like CIN and Udyam. - Onboarding & Biometrics: Provides integration guidance for KYC links, Video KYC SDKs (Web/Android/iOS), 1-Click Onboarding, DigiLocker React Native SDK, face match, face liveness, and Smart OCR. - Webhooks & Security: Documents webhook event types, HMAC-SHA256 signature verification, 2FA via IP whitelisting or RSA public key signatures, and sandbox/production base URLs. - Use Case: A fintech backend developer needs to validate beneficiary bank accounts before payouts; the skill directs them to POST /bank-account/sync, explains the async webhook trap, and warns against misusing Reverse Penny Drop. ## Quick Start Ask the assistant to show how to verify a bank account using Cashfree Secure ID penny drop with the correct headers and webhook handling.