M
API Matrix

Rejax API

Development / API Key Intermediate HTTPS
Varies by plan (check documentation)
74 Score
Grade B
Visit Official Site Compare Alternatives

Overview

Rejax provides a reverse AJAX (server-sent events / long-polling) infrastructure as a service, allowing server-side applications to push real-time updates to connected web clients without those clients needing to constantly poll your backend. Developers configure channels via the API and publish messages that are immediately delivered to all subscribed browser clients, enabling live dashboards, notifications, and collaborative features. An API key is required and authentication is managed through Rejax account credentials.

💡

Beginner Tip

Sign up at rejax.io to obtain your API key and channel credentials. The core flow is: include the Rejax client script in your HTML, have the browser subscribe to a named channel, then publish messages to that channel from your server using the REST API. Start with a simple broadcast to one channel before implementing user-specific or filtered message delivery.

Available Data

Rejax data via REST API
JSON-formatted response data
Requires API key authentication

Example Response

JSON Response 
{
  "status": "success",
  "data": {
    "result": "Data from Rejax",
    "description": "Reverse AJAX service to notify clients",
    "timestamp": "2025-01-15T10:00:00Z"
  }
}

Field Reference

success True if the message was accepted and queued for delivery to all subscribers on the specified channel
channel Name of the channel the message was published to, echoed back for confirmation
messageId Unique identifier for the published message, useful for deduplication or delivery tracking

Implementation Example 

const url = "https://rejax.io/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "X-API-Key": "YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

Clients not receiving messages The channel name in the publish request does not exactly match the channel the client subscribed to (case-sensitive)
✓ Double-check that the channel name string is identical on both the server publish call and the client subscription — even a space difference will prevent delivery
401 Unauthorized on publish endpoint API key missing from request headers or using the wrong authentication scheme
✓ Include the API key in the Authorization header as specified in the Rejax docs; verify you copied the full key without trailing whitespace
Connection drops or clients disconnecting frequently Network proxies or load balancers have short idle timeouts that close long-lived SSE connections
✓ Configure your proxy or load balancer to increase idle timeout to at least 60 seconds, or enable the Rejax heartbeat option to keep connections alive

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 10/20
🔒 Security 15/15
🛠 Developer XP 9/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth API Key
HTTPS REQUIRED
CORS NO
Category Development
Difficulty Intermediate
Verified: 2026-04-04

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