0n3
MCP servers · Mailgun · MCP server

Connect Codex CLI to Mailgun

One line gives Codex CLI your Mailgun account as tools: 8 endpoints, domains, validate email, send email, called with your own connection. No key in the prompt, a receipt for every call, revoke Codex CLI's access alone any time.

Get the line for Codex CLIConnect Mailgun first

Three steps

  1. Create a free 0n3 account and connect Mailgun. Paste a key or sign in; it lands in your vault, encrypted.
  2. Install 0n3 into Codex CLI. OpenAI's terminal agent reads 0n3 over Streamable HTTP with a token from your environment.
  3. Ask Codex CLI: whoami. Then: "Send a message in Mailgun".
Put the token in your environment
export ON3_TOKEN="<your 0n token>"

Add it to your shell profile so Codex finds it next time.

The line above carries a placeholder; 0n3.app/install mints a real key named for Codex CLI and fills it in.

What Codex CLI can then do in Mailgun

Domains · Manage sending domains7
Send a messagePOST /{domain}/messages
List domainsGET /domains
Get a domainGET /domains/{domain}
List eventsGET /{domain}/events
Get statsGET /{domain}/stats/total
List bouncesGET /{domain}/bounces
List unsubscribesGET /{domain}/unsubscribes
Validate email · Validate email addresses1
Validate emailGET /address/validate
Send email · Send emails0
Send emails
Track events · Track email events0
Track email events

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Codex CLI with other apps

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