@devioarts/capacitor-mdns

mDNS plugin for Capacitor that supports Bonjour/mDNS advertisements and discovery.

Supported platforms: ✓ iOS ✓ Android ✓ Electron

Demo (sources): application or directly file

Install

npm install @devioarts/capacitor-mdns
npx cap sync

Android

/android/app/src/main/AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />

iOS

/ios/App/App/Info.plist

<key>NSLocalNetworkUsageDescription</key>
<string>It is needed for the correct functioning of the application</string>
<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsLocalNetworking</key>
    <true/>
</dict>
<key>NSBonjourServices</key>
<array>
    <string>_http._tcp</string>
</array>

---

ElectronJS

npm i bonjour-service@1.3.0

Implementation example was developed on capacitor-electron base, if you run electron differently, you may need to adjust the code.

/electron/main.ts

// ...
import { mDNS } from '@devioarts/capacitor-mdns/electron/mdns'
// ...
const mdns = new mDNS();
// ...
app.whenReady().then(() => {
	//...
	mdns.init();
	//...
});
/* Or you can use app.on:ready (whenReady is recomended)
app.on('ready', () => {
	// ...
	mdns.init();
	// ...
});
*/

app.on('before-quit', async () => {
	// ...
	mdns.destroy();
	// ...
})
//...

electron/preload.cjs

//...
// THIS IS IMPORTANT FOR PLUGIN!
const {createMDNSAPI} = require("@devioarts/capacitor-mdns/electron/mdns-bridge.cjs");
//...
// THIS IS IMPORTANT FOR PLUGIN!
contextBridge.exposeInMainWorld('mDNS', createMDNSAPI({ ipcRenderer }));
contextBridge.exposeInMainWorld('mdns', createMDNSAPI({ ipcRenderer })) // alias

---

API

• startBroadcast(...)
• stopBroadcast()
• discover(...)
• Interfaces
• Type Aliases

Public API surface of the Capacitor mDNS plugin.

startBroadcast(...)

startBroadcast(options: MdnsBroadcastOptions) => Promise<MdnsBroadcastResult>

Start advertising a Bonjour/mDNS service.

Param	Type	Description
options	MdnsBroadcastOptions	- {@link MdnsBroadcastOptions}

Returns: Promise<MdnsBroadcastResult>

---

stopBroadcast()

stopBroadcast() => Promise<MdnsStopResult>

Stop advertising the currently registered service (no-op if none).

Returns: Promise<MdnsStopResult>

---

discover(...)

discover(options?: MdnsDiscoverOptions | undefined) => Promise<MdnsDiscoverResult>

Discover services of a given type and optionally filter by instance name.

Param	Type	Description
options	MdnsDiscoverOptions	- {@link MdnsDiscoverOptions}

Returns: Promise<MdnsDiscoverResult>

---

Interfaces

MdnsBroadcastResult

Result of startBroadcast(). Indicates whether advertising is active and the final service name. On failure, error is true and errorMessage describes the issue.

Prop	Type	Description
error	boolean	True if the operation failed.
errorMessage	string | null	Error description or null on success.
name	string	Final (possibly uniquified) service instance name. Empty on failure.
publishing	boolean	Whether the advertiser is currently active.

MdnsBroadcastOptions

Options for starting a Bonjour/mDNS advertisement.

Prop	Type	Description
type	string	Service type (including the trailing dot).
name	string	Service instance name.
port	number	TCP port to advertise.
txt	MdnsTxt	Optional TXT key–value pairs (UTF-8 strings).

MdnsStopResult

Result of stopBroadcast(). Indicates whether the advertiser is active after the call (normally false) and includes error information.

Prop	Type	Description
error	boolean	True if an error occurred while stopping.
errorMessage	string | null	Error description or null on success.
publishing	boolean	Whether the advertiser remains active (should be false on success).

MdnsDiscoverResult

Result of discover(). Contains normalized services and error information.

Prop	Type	Description
error	boolean	True if discovery encountered an error (partial results may still be present).
errorMessage	string | null	Error description or null when no error occurred.
servicesFound	number	Convenience count equal to services.length.
services	MdnsService[]	Normalized list of discovered services.

MdnsService

Normalized description of a discovered Bonjour/mDNS service. Returned from {@link mDNSPlugin.discover}.

Prop	Type	Description
name	string	Instance name of the service (may be uniqued by the OS, e.g. "My App (2)").
type	string	Full service type including the trailing dot, e.g. "_http._tcp.".
domain	string	Service domain; typically "local.".
port	number	TCP port the service advertises.
hosts	string[]	Resolved numeric IP addresses (IPv4/IPv6).
txt	MdnsTxt	TXT dictionary (key → value). Usually present on iOS; Android NSD does not populate this.

MdnsDiscoverOptions

Options for Bonjour/mDNS discovery.

Prop	Type	Description
type	string	Service type (including the trailing dot).
name	string	Optional instance name filter (prefix-safe).
timeout	number	Discovery timeout in milliseconds.
useNW	boolean	iOS-only hint to use NWBrowser instead of NetServiceBrowser.

Type Aliases

MdnsTxt

Key–value map for TXT records of a Bonjour/mDNS service. Values are UTF-8 strings; binary payloads are not supported by this API.

Record<string, string>

Record

Construct a type with a set of properties K of type T

{ [P in K]: T; }