# Production Integrations, Email Delivery & Reliability — Overview

**Document Version:** 1.0.0 (Phase 21)  
**Status:** Production Ready · 711 Automated Test Assertions Passing

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## 1. Executive Summary

LeadPilot Phase 21 establishes the production integration foundation for lead capture and follow-up communication:

```
External Communication & Lead Ingestion Layer
├── Production Email (SMTP, System, Mock) with Idempotency & Retry Classification
├── Inbound Webhook Ingestion with HMAC Verification & Replay Defense
├── Server-Side Request Forgery (SSRF) Protection for Outbound Webhooks
├── REST API Idempotency Keys (`Idempotency-Key` / `external_reference`)
└── CSV Import Hardening & Spreadsheet Formula Injection Defense
```

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## 2. Supported V1 Integration Matrix

- **Email Communication:** SMTP (custom credentials, SSL/TLS, port configuration) and System Mail transport.
- **Lead Capture:** Website Form endpoints, Unique Capture URLs, REST API (`/api/v1/leads`), Webhook Ingestion (`/api/v1/webhooks/leads/{uuid}`), CSV Import.
- **AI Qualification:** Modular provider abstraction with graceful heuristic fallback.