SignaTrust is a zero-custody e-signature platform that anchors every signed document to the blockchain, creating immutable proof of execution verifiable without any vendor. Every signing generates a cryptographic hash on a public blockchain that no party can alter, creating court-admissible permanent evidence. Three-tier signer verification with SMS OTP, biometric, and device-bound passkeys closes the bearer-token vulnerability where forwarded signing links are exploited, included on every plan. AI-powered analysis flags risks, unusual clauses, and hidden terms in plain language before signing. Documents and signing keys never touch our servers, leaving nothing to breach, subpoena, or lose. Compliance-ready for HIPAA, SOC 2, RFC 3161 timestamps, and 21 CFR Part 11 across healthcare, finance, and legal. API-first with REST API, TypeScript SDK, embedded signing, and webhooks. Native iOS and Android apps with QR scanning, offline signing, and blockchain verification.