Mailgun
Send transactional email and manage domains, mailing lists and suppressions via Mailgun
About
Mailgun ships in the w6w first-party pack. It declares 14 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.
- App id
io.w6w.mailgun- Version
- 0.2.1
- Author
- w6w
- Licence
- MIT
- Categories
- Email · Communication
Overview
Mailgun sends transactional email at scale, and this app covers the two things a workflow does with it most: sending a message — plain or with attachments — and managing the mailing lists, bounces, complaints and unsubscribes that come with running an email program responsibly.
Sending works with Mailgun’s real domain structure rather than assuming a single sender: because one account often owns several verified domains, the domain is a parameter on each send and lookup rather than fixed once at connect time, so a workflow can send from whichever verified domain fits the message. Reading recent send events, per-domain statistics, and validating an address before ever sending to it round out the set, giving a workflow the same visibility Mailgun’s own dashboard offers.
Because Mailgun operates two entirely separate deployments for its US and EU customers, the correct region for an account is set once alongside the credential, so every action reaches the right one automatically. Suppression list management — bounces, complaints and unsubscribes — is included specifically so a workflow can keep a mailing list honest rather than repeatedly sending to addresses that have already opted out or bounced.
Build with Mailgun
Three routes to the same 14 actions. The Workflow tab is generated from Mailgun's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.
Remove a complaint
complaint-delete Remove an address from the domain's spam-complaint suppression list.
Validate an email address
email-validate Check whether an email address is well-formed and deliverable.
List events
event-get-many List logged events (delivered, opened, clicked, bounced, …) for a domain.
Remove an unsubscribe
unsubscribe-delete Remove an address from the domain's unsubscribe suppression list.
A workflow step names the app and the action, and the editor fills in the
connection when you pick one. This is the Step shape from the
workflow spec, carrying Mailgun's real ids.
{
"manifestVersion": "2",
"name": "mailgun-example",
"steps": [
{
"id": "bounce-get-many",
"uses": {
"app": "io.w6w.mailgun",
"action": "bounce-get-many",
"connection": "conn_YOUR_CONNECTION_ID"
},
"with": {
"domain": "<domain>"
}
}
]
}Here are some of the things you can do
-
List bounces
readbounce-get-many -
List complaints
readcomplaint-get-many -
Get a domain
readdomain-get -
List domains
readdomain-get-many -
Validate an email address
reademail-validate
+9 more actions available
Every app-specific value here is a blank you have to fill in. An
app action is reached through the connection that authenticates it, so the
address is a connection id, not the app id — and connections belong to your account,
so a public page cannot know yours. Create one for Mailgun, then fill in
the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the
parameters that action declares. The call itself is real — the shape is transcribed
from the studio's own snippet builder, which prints the same kind of blanks — but
nothing in it is specific to Mailgun. The Workflow tab is where this app's
real ids are.
npm install @w6w/sdkyarn add @w6w/sdkpnpm add @w6w/sdkdeno add npm:@w6w/sdkimport { W6wClient, isActionRun } from "@w6w/sdk";
// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();
const envelope = await client.run({
urn: "conn_YOUR_CONNECTION_ID",
action: "message-send",
payload: {
domain: "<value>",
// sender: "<value>",
toEmail: "<value>",
subject: "<value>",
// text: "<value>",
// html: "<value>",
// sendOptions: "<value>",
// additionalFields: "<value>",
},
});
if (isActionRun(envelope)) console.log(envelope.value);npm install -g @w6w/cliw6w run conn_YOUR_CONNECTION_ID --action message-send --payload '{"domain":"<value>","toEmail":"<value>","subject":"<value>"}'Give an AI agent Mailgun — without giving it Mailgun's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.
One tool call{
"name": "w6w_invoke",
"arguments": {
"ref": "app:io.w6w.mailgun#bounce-get-many",
"input": {
"domain": "<domain>"
}
}
}
Every tool names its target with a single ref. The
app: form above doesn't name a connection at all — the
host resolves which of the caller's Mailgun connections to sign
with, and refuses rather than guesses when the answer is ambiguous.
What the agent gets
Credentials it can't read
The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.
A tool surface scoped to the caller
Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.
A durable workflow in one call
Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.
Health-aware discovery
Mailgun's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.
The MCP surface is part of the hosted platform. Mailgun itself is MIT, and the runtime that executes it is source-available (FSL).
Health checks
Mailgun declares its own checks, so its health is a property of the app rather than something the host guesses at.
Mailgun platform status
Atlassian Statuspage rollup for status.mailgun.com, with per-component detail. Unauthenticated and unsigned.
API rate-limit headroom
Requests remaining in this window, read off the `X-RateLimit-*` headers.