Long Polling

Definitions

1. A technique where the client sends an HTTP request and the server holds it open until new data is available (or a timeout expires), then responds. The client immediately sends another request, creating near-real-time updates over plain HTTP. Simpler to implement than WebSockets but less efficient for high-frequency updates.

   In plain English: A trick where the server waits to respond to a request until it actually has new data, simulating real-time updates over normal HTTP.

   Example: "Before WebSockets existed, Gmail used long polling — the browser held an open request that resolved whenever new email arrived."

Related Terms

• Webhook vs. Polling
• Event-Driven Architecture
• Circuit Breaker
• Cookie
• Game Loop
• Selector
• Server-Sent Events
• Koa
• Short Polling