MCP servers · Mailgun · connector · GPT action
Connect ChatGPT to Mailgun
One line gives ChatGPT 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 ChatGPT's access alone any time.
Three steps
- Create a free 0n3 account and connect Mailgun. Paste a key or sign in; it lands in your vault, encrypted.
- Install 0n3 into ChatGPT. A custom connector in Developer mode, or an Action on a custom GPT from the OpenAPI spec.
- Ask ChatGPT: whoami. Then: "Send a message in Mailgun".
Custom connector (needs Developer mode)
- Settings → Connectors (or Apps) → Advanced → Developer mode on
- Create → name 0n3 · MCP server URL https://0n3.app/mcp · Authentication: OAuth
- Finish the sign-in with your 0n account
- Enable the connector in a chat and ask: "whoami"
ChatGPT connectors cannot send a static header, so 0n3 signs you in through its OAuth door (dynamic client registration is on).
The line above carries a placeholder; 0n3.app/install mints a real key named for ChatGPT and fills it in.
What ChatGPT can then do in Mailgun
Domains · Manage sending domains7
Send a message
POST /{domain}/messagesList domains
GET /domainsGet a domain
GET /domains/{domain}List events
GET /{domain}/eventsGet stats
GET /{domain}/stats/totalList bounces
GET /{domain}/bouncesList unsubscribes
GET /{domain}/unsubscribesValidate email · Validate email addresses1
Validate email
GET /address/validateSend email · Send emails0
Send emails
Track events · Track email events0
Track email events
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