replit-load-scale

name	replit-load-scale
description	Load test and scale Replit deployments with Autoscale tuning, Reserved VM sizing, and capacity planning. Use when load testing Replit apps, optimizing Autoscale behavior, or planning capacity for production traffic. Trigger with phrases like "replit load test", "replit scale", "replit capacity", "replit performance test", "replit autoscale tuning".
allowed-tools	Read, Write, Edit, Bash(npx:*), Bash(curl:*)
version	1.12.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","replit","testing","performance","scaling"]
compatibility	Designed for Claude Code, also compatible with Codex and OpenClaw

Replit Load & Scale

Overview

Load testing, scaling strategies, and capacity planning for Replit deployments. Covers Autoscale behavior tuning, Reserved VM right-sizing, cold start optimization, database connection scaling, and capacity benchmarking.

Prerequisites

• Replit app deployed (Autoscale or Reserved VM)
• Load testing tool: k6, autocannon, or curl
• Health endpoint implemented

Replit Scaling Model

Deployment Type	Scaling Behavior	Cold Start	Best For
Autoscale	0 to N instances based on traffic	Yes (5-30s)	Variable traffic
Reserved VM	Fixed resources, always-on	No	Consistent traffic
Static	CDN-backed, infinite scale	No	Frontend assets

Instructions

Step 1: Baseline Benchmark

# Quick benchmark with autocannon (built into Node.js ecosystem)
npx autocannon -c 10 -d 30 https://your-app.replit.app/health
# -c 10: 10 concurrent connections
# -d 30: 30 seconds duration

# Output shows:
# - Requests/sec
# - Latency (p50, p95, p99)
# - Throughput (bytes/sec)
# - Error count

Step 2: Load Test with k6

// load-test.js — comprehensive Replit load test
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

const errorRate = new Rate();
 coldStartTrend =  ();

  options = {
  : [
    { : , :  },    
    { : , :  },   
    { : , :  },   
    { : , :  },    
  ],
  : {
    : [],  
    : [],              
  },
};

  = __ENV. || ;

   () {
  
   healthRes = http.();
  (healthRes, {
    :  r. === ,
    :  r.. < ,
  });
  errorRate.(healthRes. !== );

  
   (healthRes.. > ) {
    coldStartTrend.(healthRes..);
  }

  
   apiRes = http.();
  (apiRes, {
    :  r. === ,
  });

  ();
}