Mail Gun

This prefab sends email through Mailgun from a cloud function. The API key never reaches the browser: it is read server-side by a Secret node, and the graph only ever carries its name.

What you must provision

Secret name	What it is	Credential?
MAILGUN_API_KEY	Your Mailgun private API key	yes
MAILGUN_DOMAIN	The sending domain, e.g. mg.example.com	no — but it differs per deployment, so it lives in the same place

Both are read through the same door. MAILGUN_DOMAIN is not a secret; it is here because the functions secret store is the one mechanism a cloud function has for reading a named, per-deployment value, and splitting the two would give this prefab two configuration mechanisms, one of which fails silently.

Until both are provisioned, Send Email fires Failure and the backend logs which name is missing. It never sends with a blank key or an empty domain.

The two ways to provision them

1. The secrets file — <dataDir>/secrets.json on the machine running the backend, under the functions section:

{
  "functions": {
    "MAILGUN_API_KEY": "key-xxxxxxxxxxxxxxxxxxxx",
    "MAILGUN_DOMAIN": "mg.example.com"
  }
}

Read-modify-write the whole file: it also holds the backend's admin token and webhook secrets.

2. Environment variables — for deploy targets that provision env vars rather than a data directory:

NODEGX_SECRET_MAILGUN_API_KEY=key-xxxxxxxxxxxxxxxxxxxx
NODEGX_SECRET_MAILGUN_DOMAIN=mg.example.com

The file wins if both are set.

⚠️ secrets.json is machine-local and does not travel with a deploy. A prefab that works on your machine and fails in production is almost always a secret nobody provisioned on that target.

Using it

/#__cloud__/MailGun/Send Email takes To, From, Subject, Html or Text, CC, BCC and a Do signal, and answers Success or Failure. Do fetches both values first and runs the send once they have arrived.

/#__cloud__/MailGun/Settings is the component that does the fetching — Fetch in, API Key + Domain Name + Ready + Failure out.