New

• security: CC/BCC suppression guards, deterministic IP hash, domain cache invalidation, custom headers
• smtp: VERP return-path for reliable bounce-to-email matching
• api: add domain cache and configurable DB pool for higher throughput
• api: add hard bounce suppression, pagination with total counts, and test webhook delivery
• api: add idempotency keys, account endpoint, bounce buffer limit, webhook auto-recovery
• api: add OpenAPI documentation with Swagger UI
• api: add SHA-256 API key cache and optimize auth + Docker setup
• domains: generate DKIM keypairs at registration and implement DNS verification
• euromail: implement complete transactional email service
• helm: add production hardening with security contexts, probes, PDBs, and alerting
• observability: add Prometheus metrics and OpenTelemetry OTLP tracing
• ops: add composite DB indexes, worker readiness probe, and template render timeout
• ops: add cross-process API key cache invalidation, worker port dedup, and dashboard error logging
• quota: replace DB quota with Redis atomic counting and partition emails table
• resilience: add graceful shutdown, DB pool hardening, and worker task draining
• resilience: domain validation, quota batch sync, JWT pinning, and orphan prevention
• security: add CSPRNG, SSRF protection, security headers, per-account rate limits, login brute-force guard
• security: add email validation, body size limits, template fuel cap, and streaming webhook reads
• security: bounce guard, partition pruning, config validation, template tenant isolation
• security: bounce tenant isolation, webhook HMAC timestamps, SDK contract fixes
• security: dashboard tenant isolation, input validation, SDK response alignment
• smtp: add stream MAXLEN, multi-IP pool, warm-up schedule, circuit breakers
• smtp: enforce STARTTLS, recover stuck emails, harden webhooks and session cookies
• worker: add webhook retry with exponential backoff and HTML-to-plaintext fallback

Fixed

• data-integrity: orphan cleanup, bounce scoping, DKIM generation, quota reset, SDK fixes