Mailgun sends it. Notifly decides when and to whom.

These are the fields the dashboard asks for when you connect Mailgun, quoted from the create form.

• Base URL. Empty means https://api.mailgun.net; use https://api.eu.mailgun.net for an EU account. No other host is accepted.
• Domain. Every message is created on this sending domain.
• From email address and Sender name. Combined into Sender name <address> on every email.

1. Sign in at app.notifly.io, open Integration Store in the sidebar and choose Connect Provider.
2. In the Connect Integration sheet, open the E-Mail tab (or search across channels), find Mailgun and choose Connect.
3. Pick the environment the integration belongs to. Development and Production keep separate integrations, so you can point each at a different Mailgun account or key.
4. Fill in Delivery Provider Credentials with the fields in the table above, then choose Create Integration.
5. A new integration starts switched on as both Active Integration and Primary Integration, so email steps in that environment send through Mailgun by default. If the environment already has a primary email integration, the dashboard asks before replacing it.

Your backend triggers a workflow; Notifly renders the email step and sends it through Mailgun. The subscriber is created or updated from to on the way.

// npm install @notiflyio/api@0.1.26
import { Notifly } from "@notiflyio/api";

const notifly = new Notifly({ security: { secretKey: process.env.NOTIFLY_SECRET_KEY } });

await notifly.trigger({
  workflowId: "order-shipped",
  to: { subscriberId: "user_123", email: "ada@example.com" },
  payload: { orderId: "A-1042", trackingUrl: "https://example.com/track/A-1042" },
  overrides: {
    // oTag reaches Mailgun as o:tag.
    providers: { mailgun: { oTag: ["order-shipped"] } },
  },
});

Prefer plain HTTP? The same trigger is POST https://api.notifly.io/v1/events/trigger with an Authorization: ApiKey header and a body of { "name", "to", "payload" }.

• Mailgun's o: and t: options. Written in camelCase on the trigger and mapped to Mailgun's names, including o:tag, o:tracking, o:deliverytime, o:require-tls and t:version.
• Headers. Custom headers go out as h: fields; reply-to as h:Reply-To.
• Recipients and files. Cc and bcc as comma-separated lists; attachments with a content id as inline parts, the rest as attachments.
• Per step, if you need it. overrides.steps.<stepId>.providers.mailgun applies to one email step and wins over the workflow-wide value.