hardSystem Design

What is the purpose of the HTTP Agent in Node.js?

Q: What is the purpose of the HTTP Agent in Node.js?

**TL;DR.** An http.Agent manages a **pool of sockets** for outgoing HTTP requests, enabling **keep-alive** connection reuse so you don't pay TCP+TLS setup on every call. It also caps concurrent sockets per host ( maxSockets ) and queues the rest — crucial for high-throughput clients. req 1 req 2 req 3 <path

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Evaluates knowledge of connection persistence and HTTP pooling on the client-side.

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Keep-alive agent for outbound calls

import http from 'node:http';

const agent = new http.Agent({
  keepAlive: true,
  maxSockets: 50,          // cap concurrency per host
  keepAliveMsecs: 10_000,
});

http.get('http://api.internal/health', { agent }, (res) => { /* ... */ });
// Sockets are reused across requests instead of reconnecting each time.

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