Blog

Notes on cold email infrastructure

November 2, 2026 · 6 min read

Why domain reputation decides whether your cold email lands

Your sending domain is your credit score. How aged domains, SPF/DKIM alignment, and warmup windows shape inbox placement — and how sendzy keeps them clean.

October 21, 2026 · 5 min read

Hosting multiple domains on one mail server (without burning them)

1 domain, 1 instance, 3 mailboxes is the safe default. When you can pack 2 domains on one server, and when custom SMTP/IMAP overrides are the better call.

October 9, 2026 · 4 min read

Letting agents send email: MCP for cold outreach

The Model Context Protocol turns Claude and Cursor into outreach operators. A tour of the sendzy MCP tools — domains, mailboxes, campaigns, threads and sending.

September 25, 2026 · 8 min read

Inside a private mail server: what actually gets installed

A tour of the stack behind every sendzy instance: mail transfer, authentication, TLS, storage — and the handful of config lines that make it behave.