⚡ Emitra

Free, lightweight real-time WebSocket client for building event-driven applications.

100% Free Forever — no credit card, no trial limits. Get your free App Key at evnt-flow.com and start streaming events in minutes.

🚀 Installation

npm install emitra-js

🔑 Get Your Free App Key

1. Go to evnt-flow.com
2. Create a free account
3. Copy your App Key from the dashboard
4. Use it in the code below — that's it!

⚡ Quick Start

import Emitra from 'emitra-js'

const ef = new Emitra('YOUR_APP_KEY')
const channel = ef.subscribe('my-channel')

// Listen for incoming messages from OTHER clients
// Note: sender does NOT receive their own messages
channel.on('my-event', (data) => {
  console.log('Received:', data)
})

// Send a message — other subscribers will receive it
channel.trigger('my-event', { message: 'hello world' })

⚠️ Important: The sender does not receive their own messages. Only other subscribers on the same channel will receive them. To test, open two browser tabs or run two Node.js processes.

🌐 Browser Usage

<script src="https://cdn.socket.io/4.8.1/socket.io.min.js"></script>
<script src="https://cdn.evnt-flow.com/emitra/v1/emitra.min.js"></script>

<script>
const ef = new Emitra('YOUR_APP_KEY')
const channel = ef.subscribe('my-channel')

channel.on('my-event', (data) => {
  console.log('Received:', data)
})

channel.trigger('my-event', { message: 'hello world' })
</script>

✨ Features

| | Feature | |---|---| | 🆓 | Free forever — no hidden fees, no paywalls | | ⚡ | Real-time communication via WebSocket | | 🧩 | Channel-based pub/sub architecture | | 🔁 | Automatic reconnection with exponential backoff | | 🪶 | Lightweight (~5KB) and zero config | | 🔒 | Secure WSS connections | | 📦 | Works in Node.js and Browser |

📦 API Reference

new Emitra(appKey, options?)

Create a new client instance.

| Parameter | Type | Description | |---|---|---| | appKey | string | Required. Your App Key from evnt-flow.com | | options.host | string | WebSocket server URL (default: wss://wss.evnt-flow.com) | | options.debug | boolean | Enable debug console logs (default: false) |

const ef = new Emitra('YOUR_APP_KEY', { debug: true })

ef.subscribe(channelName) → EmitraChannel

Subscribe to a channel. Returns a channel object.

const channel = ef.subscribe('chat-room')

channel.on(eventName, callback) → this

Listen for a specific event on this channel.

channel.on('new-message', (data) => {
  console.log(data)
})

channel.trigger(eventName, data) → this

Send an event to the channel. All other subscribers will receive it.

channel.trigger('new-message', { text: 'Hi there!' })

💡 The sender is excluded from the broadcast — only other clients receive the message.

channel.off(eventName) → this

Remove an event listener.

channel.off('new-message')

ef.unsubscribe(channelName)

Unsubscribe from a specific channel.

ef.disconnect()

Disconnect from the server and clean up all subscriptions.

ef.onError(callback)

Listen for server-side errors (subscription errors, rate limit blocks, etc.)

ef.onError((err) => {
  console.error('Emitra error:', err)
})

ef.connected() → boolean

Check if the client is currently connected.

🧪 Testing

To test message delivery locally:

1. Open two terminals (or two browser tabs)
2. Both connect with the same App Key and subscribe to the same channel
3. Send from one → receive in the other

The sender never receives their own messages — this is by design.

📁 Example

See the /example folder for a full interactive test client with UI.

🆓 Pricing

Emitra is free forever with generous limits:

• ✅ 50 messages/sec
• ✅ 500 peak connections
• ✅ 1 App Key
• ✅ Unlimited channels

Need more? Check out paid plans at evnt-flow.com.

📄 License

MIT © Emitra