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Email infrastructure, explained for builders
Operational guides for sending expected email, receiving replies, protecting reputation and giving agents constrained access.
Inbound Email
How to Receive Email with Amazon SES: S3 and Lambda
Build a production-ready inbound email pipeline with Amazon SES, S3, and Lambda, including MIME safety, tenant routing, idempotency, retries, and threading.
Read article →Email APIs
Amazon SES Pricing Tiers Explained (July 2026)
Amazon SES shifted from a simple a la carte model to tiered plans (Essentials, Pro, Enterprise) on July 21, 2026. Here is the cost breakdown and what it means for your transactional email budget.
Read article →Domain Authentication
DMARC p=none vs Quarantine vs Reject: An Operator's Guide
Choosing the right DMARC policy is a balancing act between security and deliverability. Learn the safe rollout path from p=none to p=reject to prevent spoofing without blocking legitimate mail.
Read article →Engineering
Idempotency Keys for Email APIs
Prevent duplicate emails during network retries by implementing idempotency keys. Learn how to handle distributed system failures without spamming your users.
Read article →Domain Authentication
SPF Flattening: Fixing the 10-Lookup Limit
Stop the 'permerror' caused by too many DNS lookups. Learn how SPF flattening works, why the 10-lookup limit exists, and how to resolve include chains for better deliverability.
Read article →Deliverability
Bounce vs Complaint: What Actually Hurts Deliverability
Bounces are technical failures, but complaints are reputation killers. Learn how to handle both to keep your sending reputation intact and your emails landing in the inbox.
Read article →Engineering
Designing Email Webhooks for At-Least-Once Delivery
Learn how to build resilient webhook consumers for email events using retries, idempotency keys, and signature verification to ensure no delivery event is ever missed.
Read article →Engineering
The Transactional Email Migration Playbook
Migrating transactional email providers without losing observability requires a phased approach: dual-sending, event parity mapping, and gradual DNS cutovers.
Read article →Email APIs
Why the Same 50,000 Emails Cost $5 or $66
A deep dive into the pricing spread of email APIs. We analyze why the same 50k volume varies by 13x across providers and how to choose based on your engineering constraints.
Read article →Email APIs
SendGrid Free Plan Is Gone: A 30-Minute Migration Guide
SendGrid's free tier is now a 60-day trial. Here is a technical guide for engineers to migrate their transactional email to a sustainable alternative without downtime.
Read article →Email APIs
Resend-Compatible Email APIs: What Compatibility Does Not Cover
API compatibility allows you to switch providers without rewriting your code, but it does not migrate your reputation, DNS records, or deliverability history.
Read article →Engineering
Transactional Email API Production Checklist
A technical guide for engineers launching transactional email systems. Covers DNS verification, idempotency, error handling, and cost analysis for production readiness.
Read article →Agent Workflows
How to Give an AI Agent Safe Email Sending Access
Giving an AI agent an API key is a liability. Learn how to implement scoped credentials, approval boundaries, and idempotency to prevent agent-driven email disasters.
Read article →