Bedlam

A chaos engineering library that randomly rejects API fetch requests to test your site's reliability.

Installation

npm install @agwnl/bedlam
# or
pnpm add @agwnl/bedlam
# or
yarn add @agwnl/bedlam

Usage

import { enableChaos, disableChaos } from "@agwnl/bedlam";

// Enable chaos mode
enableChaos({
  failRate: 0.3, // 30% of requests will fail (default: 0.2)
  delayMs: 1000, // Add 1s delay to all requests (default: 0)
  mode: "reject", // 'reject' or 'http-500' (default: 'reject')
  include: ["/api/"], // Only affect URLs containing these strings (default: [])
  exclude: ["/health"], // Never affect URLs containing these strings (default: [])
});

// Disable chaos mode
disableChaos();

Error Modes

• reject: Simulates network failures (promise rejection)
• http-500: Simulates server errors (returns HTTP 500 response)

Example

import { enableChaos } from "@agwnl/bedlam";

// Enable chaos in development
if (process.env.NODE_ENV === 'development') {
  enableChaos({ failRate: 0.2 });
}

// Your app will now randomly fail 20% of fetch requests
fetch('/api/users').then(...).catch(...);