How to Build a Mobile Backend in Minutes - Realtime Auth, DB, Storage (React Native+Expo)

Volodymyr — Tue, 05 Aug 2025 15:51:46 +0000

Real-Time Backend for Mobile Apps Without WebSockets: A Modern Pub/Sub Alternative

Volodymyr — Thu, 03 Jul 2025 18:49:16 +0000

Looking for a real-time backend for your mobile app without managing WebSockets? In this post, I’ll show how to enable real-time pub/sub messaging on mobile — with no WebSocket server, no API keys, and no infrastructure headaches.

Whether you’re building chat apps, collaborative tools, or live dashboards, real-time data is critical for a great user experience. But building and scaling a secure real-time backend is one of the hardest parts of mobile development.

We built Calljmp to change that.

The Problem With WebSockets for Mobile Apps

WebSockets are a common choice for real-time messaging. But they come with challenges — especially on mobile:

Complex to scale across regions
Require constant connection management
Prone to disconnects, especially on flaky networks
Difficult to secure (especially with API keys)
Need additional infrastructure for authentication and data filtering

If you’ve tried to build real-time experiences with WebSockets or Firebase Realtime Database, you’ve probably run into these issues.

A WebSocket-Free Real-Time Backend for Mobile Developers

Calljmp provides real-time pub/sub messaging built for mobile apps — without WebSockets or complex infrastructure.

Instead of persistent WebSocket connections, Calljmp uses a hybrid architecture (HTTP/2, Durable Objects, edge messaging) to deliver low-latency updates at scale. It supports:

Structured pub/sub channels like presence.users.online
Field-level projection (receive only the data you need)
Filter queries (similar to MongoDB syntax)
React Native and Flutter SDKs
Mobile-first authentication (App Attestation and Play Integrity API)

All backed by Cloudflare’s edge network for global performance.

Secure Real-Time Messaging Without API Keys

Calljmp avoids one of the biggest security pitfalls of mobile APIs: API keys.

Instead, Calljmp uses App Attestation on iOS and Play Integrity on Android to verify requests directly from your app — at runtime.

This protects your backend from abuse and ensures messages are only sent and received by valid, verified apps.

Example: Real-Time Chat on Mobile

Let’s say you want to implement chat in your mobile app. Here’s how it works with Calljmp:

Create a channel: chat.rooms.1234
Subscribe to updates using the SDK:

   calljmp.subscribe("chat.rooms.1234", (message) => {
     // update UI with new message
   });

Publish new messages:

   calljmp.publish("chat.rooms.1234", {
     user: "Alice",
     text: "Hey there!",
     timestamp: Date.now()
   });

Optional: Add filters to only receive messages from specific users, or project only the text and timestamp fields to reduce payload size.

Real-Time Pricing That’s Developer-Friendly

Unlike Firebase or Supabase, Calljmp doesn’t charge for:

Persistent connections
Outgoing messages
Idle app activity

You only pay for what you use — based on volume of published messages and data storage. It’s a transparent, scalable pricing model for mobile teams.

Explore Calljmp pricing

Why Developers Use Calljmp for Real-Time Mobile Backends

Mobile-first design (React Native & Flutter support)
On-edge SQLite database with low-latency access
Auto-scaling backend with zero infrastructure management
Global replication and CDN-level performance
30-day backup retention for reliability
No project suspensions due to inactivity (unlike Firebase)

Whether you’re an indie developer or a growing mobile app studio, Calljmp offers the building blocks for secure, fast, real-time apps — without reinventing the backend.

It is now live with real-time pub/sub for mobile apps. You can:

Set up in minutes
Build chat, presence, and collaborative features
Skip WebSockets entirely
Go live without maintaining any servers

Start building: https://calljmp.com

DEV Community: Volodymyr