# Developer Reference — Integrations & Delivery Architecture

**Document Version:** 1.0.0 (Phase 21)

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## 1. Core Services

- **`EmailDeliveryService`**: Dispatches outbound email via configured transport (`SmtpMailProvider`, `SystemMailProvider`, `MockMailProvider`), enforcing idempotency keys and classifying errors.
- **`WebhookAdapterService`**: Verifies HMAC-SHA256 signatures, provides event replay protection, maps arbitrary payloads to `CanonicalLeadInput`, and logs diagnostic history.
- **`SsrfProtectionService`**: Validates destination URLs against internal and private IPv4/IPv6 CIDR blocks.
- **`CsvImportService`**: Hardens spreadsheet imports against formula injection attacks.