Writing

Notes for people who send email from software

Deliverability, authentication, agents and the parts of email that only bite in production.

Give your AI a send button

Connecting an MCP email server to Claude or ChatGPT, what a model can then do end to end — and why guardrails matter far more when the sender is a process nobody is watching.

The three DNS records that decide whether your email arrives

SPF, DKIM and DMARC for people who ship apps rather than run mail servers: what each actually checks, why alignment is the thing that trips everyone, and the warmup rules nobody mentions.

Choosing an email API in 2026

Postmark, Resend, Brevo and Charlie compared on pricing model, EU residency, marketing support and agent access — including where each one is the wrong answer.