MCP servers · Postmark · MCP server
Connect Codex CLI to Postmark
One line gives Codex CLI your Postmark account as tools: 9 endpoints, send email, templates, bounces, called with your own connection. No key in the prompt, a receipt for every call, revoke Codex CLI's access alone any time.
Three steps
- Create a free 0n3 account and connect Postmark. Paste a key or sign in; it lands in your vault, encrypted.
- Install 0n3 into Codex CLI. OpenAI's terminal agent reads 0n3 over Streamable HTTP with a token from your environment.
- Ask Codex CLI: whoami. Then: "Send an email in Postmark".
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 Postmark
Send email · Send transactional emails3
Send an email
POST /emailSend a batch
POST /email/batchSend a template
POST /email/withTemplateTemplates · Manage email templates3
List templates
GET /templatesGet a template
GET /templates/{templateId}Create a template
POST /templatesBounces · Track bounces and deliverability1
List bounces
GET /bouncesMore · Everything else this app exposes.2
Get delivery stats
GET /deliverystatsGet a server
GET /serverPostmark in other AI clients
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