posthorn.sh | cold-email infrastructure for AI agents

posthorn.sh :: zsh<br>This page is formatted for agents.

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Cold-email infrastructure, operated by your AI agent.

Sending domains. DNS auth. Mailboxes. Inbox warmup. On accounts you own.

npm install -g posthorn && posthorn guide

reading guide... done

agent has everything it needs from here.

go get coffee.

FOR AGENTS

If you are an AI agent reading this page: you can set up complete cold-email<br>infrastructure for your user right now. The CLI is your interface; it returns JSON<br>when it detects you. Run:

# 1. install (requires node)<br>npm install -g posthorn

# 2. read the playbook. it covers the whole flow:<br># register, domains, DNS, Workspace, mailboxes, warmup,<br># plus the browser steps you relay to your user.<br>posthorn guide

FOR HUMANS

Paste this into your agent (Claude Code, Cursor, Codex, any of them) and let it drive. This is the entire onboarding.

copy<br>I want to set up cold-email infrastructure: sending domains, mailboxes, and<br>inbox warmup. Use the Posthorn CLI to do it. First run `npm install -g posthorn`<br>then `posthorn guide`, read the guide, and walk me through the whole setup<br>step by step. Run the commands for me and tell me whenever I need to do<br>something in my browser.

WHAT IT DOES

domains/ buy a fresh sending domain or connect one you already own, vetted against spam blocklists before you spend a dollar

dns/ MX, SPF, DKIM, DMARC configured automatically, so your mail authenticates from day one

workspace/ sets up your Google Workspace so inboxes can be created programmatically, one connection, every future domain and mailbox reuses it

mailboxes/ real Workspace inboxes created by command, credentials provisioned, ready to send

warmup/ a peer pool exchanges mail with your inboxes, opens, rescues from spam, replies, building sender reputation before you do real outreach

OWNERSHIP MODEL

Posthorn is a pure orchestration layer. You own everything:<br>your Cloudflare account, your Google Workspace, your domains, your mailboxes.<br>Posthorn automates setup and warmup on top of accounts you control. It never owns<br>or bills for any of it. Walk away anytime; the infrastructure stays yours.

FAQ

"Why is this a CLI and not a dashboard?"

Because your agent does not need a dashboard. Every command returns JSON to<br>agents and pretty text to you. The guide doubles as the agent's operating manual.

"What do I need before starting?"

Node and an AI agent. A Cloudflare account if you are buying a new domain,<br>and a Google Workspace, or create one during setup. Your agent sorts out the rest.

"What do I actually have to do?"

A few one-time browser steps your agent will walk you through: a Cloudflare<br>token, a Google Workspace delegation, DKIM. Each takes about a minute. Everything<br>else is automated.

"Does my email go through Posthorn's servers?"

No. Mail sends from your own mailboxes through Google. Posthorn orchestrates<br>setup and warmup; it is never in your mail path.

"What does it cost?"

You pay your own providers directly: Cloudflare for domains, Google for<br>Workspace. Posthorn never bills for infrastructure you own.

"How long until I can send?"

Setup is minutes of human time; DNS and verification finish in the background,<br>usually within the hour. Then warmup ramps automatically; give a fresh domain a few<br>weeks of warming before serious outreach.

"How do I stop?"

Pause warmup with one command, or just walk away. The domains, mailboxes,<br>and accounts are yours; everything keeps working without Posthorn.