Used For

• +**Your Arduino sensors update a dashboard every 5 seconds but your PHP polling breaks constantly** → PubNub handles real-time updates automatically, no more refresh button spam
• +**You're building a collaborative app where users need to see changes instantly** → Messages appear in under 100ms across all connected devices
• +**Your chat feature works fine with 50 users but dies at 1,000** → Scales to 3 million concurrent users without you managing servers
• +Works with 70+ programming languages - your weird embedded device probably has an SDK
• +Handles presence detection - see who's online/offline without building it yourself

Best For

• >Building IoT prototypes that need live sensor data without server headaches
• >Adding real-time chat to your app without becoming a WebSocket expert
• >Your custom messaging setup keeps crashing at 10k users

Not For

• -Solo developers just learning to code — the free tier's 25 device limit is more restrictive than it sounds
• -Anyone building basic CRUD apps without real-time features — you're paying for speed you don't need
• -Teams wanting to self-host everything — it's cloud-only, no on-premise option

Pairs With

• *Arduino/Raspberry Pi (the actual sensors sending temperature, motion, or whatever data you're tracking)
• *React/Vue.js (for the web dashboard where humans watch the real-time data come in)
• *Node.js/Python (your backend that processes messages before sending them to PubNub)
• *PostgreSQL (to store message history since PubNub's storage gets expensive)
• *AWS Lambda (for serverless functions triggered by incoming PubNub messages)
• *Particle.io (popular with makers for easy IoT prototyping, integrates directly with PubNub)

The Catch

• !The free 250k messages/month sounds generous until you realize IoT sensors chattering every few seconds eat through it fast
• !You'll spend more time than expected figuring out message routing and channel naming as you scale
• !Usage-based pricing means your costs are unpredictable if your app takes off

Bottom Line

Saves you from building your own chat servers, but you'll pay per message once you outgrow the tiny free tier.