websockets
WebSockets Study Guide
What is a WebSocket?
A WebSocket is:
a persistent real-time communication connection between two systems.
Unlike normal REST APIs:
- the connection stays open
- both systems can send data anytime
Simple Explanation
REST API
Client asks for information repeatedly.
Example:
"Any new messages?"
"Any new messages?"
"Any new messages?"
WebSocket
Connection stays open continuously.
Server pushes updates instantly:
"New message received"
without client repeatedly asking.
Why WebSockets Exist
WebSockets enable:
real-time communication
Examples:
- live chat
- agent status updates
- notifications
- voice/video signaling
- stock market feeds
- multiplayer gaming
Common WebSocket Use Cases
| Use Case | Example |
|---|---|
| Live Chat | Customer-agent messaging |
| Agent Presence | Agent online/offline updates |
| Notifications | Real-time alerts |
| Voice/Video Apps | Session signaling |
| Monitoring Dashboards | Live metrics |
| Collaboration Tools | Real-time updates |
How WebSockets Work
Step 1 — Client Connects
Example:
Browser → WebSocket Server
Step 2 — Connection Upgraded
Initial connection starts using HTTP/HTTPS.
Then upgraded to:
WebSocket protocol
Step 3 — Persistent Connection Established
Connection remains:
continuously open
Both sides can send data anytime.
WebSocket Communication Flow
Client ↔ WebSocket Server
Bidirectional communication.
REST API vs WebSocket
| REST API | WebSocket |
|---|---|
| Request/response | Persistent connection |
| Stateless | Stateful |
| Client initiates requests | Both sides send data |
| Polling often required | Real-time updates |
| Short-lived connection | Long-lived connection |
Simple Analogy
REST API
Like sending emails:
- request
- response
- connection closes
WebSocket
Like phone call:
- connection stays active
- both sides talk anytime
Example WebSocket Flow
Customer sends message
↓
Agent instantly receives message
↓
Agent replies immediately
↓
Customer sees reply in real time
No repeated API polling needed.
WebSocket URLs
Instead of:
https://
WebSockets use:
ws://
Secure WebSockets:
wss://
Secure WebSockets
WSS = WebSocket Secure
Equivalent of:
HTTPS for WebSockets
Uses:
- TLS encryption
- secure communication
VERY important in:
- banking
- enterprise platforms
- customer interactions
Why WebSockets Matter In Glia
Glia heavily relies on:
- real-time chat
- live agent updates
- voice interactions
- customer engagement
WebSockets are commonly used for:
- live interaction synchronization
- agent presence
- messaging
- session updates
WebSockets vs Webhooks
| WebSocket | Webhook |
|---|---|
| Persistent connection | One-time event notification |
| Real-time bidirectional | Event-based push |
| Both sides communicate | Source system pushes |
| Continuous session | Stateless notification |
WebSockets vs REST APIs
| REST API | WebSocket |
|---|---|
| Request/response | Continuous communication |
| Polling required for updates | Instant updates |
| Better for CRUD operations | Better for real-time apps |
CRUD:
- Create
- Read
- Update
- Delete
Common WebSocket Troubleshooting
Problem 1 — Connection Fails
Possible causes:
- firewall blocking
- proxy issues
- incorrect endpoint
- TLS/certificate issue
Problem 2 — Connection Drops
Possible causes:
- timeout
- network instability
- load balancer session timeout
Problem 3 — TLS/WSS Failure
Symptoms:
- secure connection rejected
- certificate errors
Check:
- TLS certificates
- HTTPS/WSS configuration
Problem 4 — Authentication Failure
Some WebSockets require:
- bearer token
- session authentication
- OAuth validation
Result: connection rejected.
Problem 5 — High Latency
Symptoms:
- delayed chat messages
- slow updates
Possible causes:
- network congestion
- overloaded server
- scaling issues
WebSocket Troubleshooting Flow
Step 1 — Validate Endpoint
Check:
ws://
or:
wss://
Step 2 — Validate Connectivity
Check:
- firewall
- proxy
- load balancer
- port access
Step 3 — Validate Authentication
Check:
- bearer token
- OAuth session
- API credentials
Step 4 — Validate TLS/WSS
Check:
- certificate validity
- TLS compatibility
- HTTPS/WSS support
Step 5 — Review Logs
Check:
- WebSocket handshake logs
- disconnect reasons
- timeout events
- session logs
Common Interview Questions
“What is a WebSocket?”
Good Answer:
“A WebSocket is a persistent bidirectional communication protocol that enables real-time data exchange between systems over a continuously open connection.”
“Difference between REST API and WebSocket?”
Good Answer:
“REST APIs use a request/response model with short-lived connections, while WebSockets maintain a persistent connection that supports real-time bidirectional communication.”
“Why use WebSockets?”
Good Answer:
“WebSockets are ideal for real-time applications such as live chat, notifications, voice signaling, and agent presence updates because they eliminate the need for continuous polling.”
“Difference between WebSocket and webhook?”
Good Answer:
“WebSockets maintain a persistent real-time communication session, while webhooks are one-time event notifications triggered when specific events occur.”
“How would you troubleshoot WebSocket issues?”
Good Answer:
“I would validate endpoint connectivity, verify firewall and proxy access, confirm authentication and TLS configuration, review handshake and disconnect logs, and isolate any network or session timeout issues.”
Important Security Concepts
Secure WebSockets should use:
WSS (WebSocket Secure)
This provides:
- TLS encryption
- secure communication
- token protection
Easy Memory Trick
REST API = Request/Response
Webhook = Event Notification
WebSocket = Live Continuous Conversation
Important Terms To Know
| Term | Meaning |
|---|---|
| WebSocket | Persistent real-time connection |
| WSS | Secure WebSocket |
| Bidirectional | Both sides communicate |
| Persistent Connection | Connection remains open |
| Polling | Repeated API requests |
| Real-Time | Instant communication |
| Handshake | Initial connection setup |
| Stateful | Maintains session state |