Sending Pipeline & Infrastructure Audit

sending-pipeline-infrastructure · v1.1.0 · paid

Audits email sending infrastructure including queue architecture, ESP integration patterns, template rendering security, retry strategies, and failure isolation for campaign systems.

Queue Architecture

queue-architecture · weight 0.3

Queue backed by durable persistent storage
ab-002442
critical
Dead letter queue for permanently failed sends
ab-002457
high
Queue jobs include campaign and recipient identifiers for traceability
ab-002459
high
At-least-once delivery with deduplication guard
ab-002458
high
Message priority separates transactional from marketing
ab-002455
low
Message ordering preserves campaign sequence
ab-002456
low

ESP Integration

esp-integration · weight 0.25

ESP API credentials stored in environment variables
ab-002454
critical
ESP abstracted behind a common interface
ab-002462
high
Delivery status via webhooks, not polling
ab-002460
high
ESP response codes mapped to internal status model
ab-002464
medium
ESP health check validates connectivity before processing
ab-002461
low
Multi-ESP fallback routing configured
ab-002463
info

Template Engine

template-engine · weight 0.25

Merge fields sanitized to prevent header injection
ab-002469
critical
Templates rendered server-side
ab-002466
high
HTML validated against common email clients
ab-002465
medium
Unsubscribe link injected automatically
ab-002467
high
Template versioning tracks breaking changes
ab-002468
low
Plain-text alternative generated for all HTML emails
ab-002448
info

Retry & Error Handling

retry-error-handling · weight 0.2

Retries use exponential backoff
ab-002450
high
Retry limit set with dead letter escalation
ab-002452
high
Retries are idempotent — no duplicate sends
ab-002451
critical
Permanent failures do not retry
ab-002453
medium
Temporary failures do not block the rest of the queue
ab-002449
medium