errorlens-express

Official SDK for ErrorLens — self-hosted, AI-native error tracking. Captures errors from your Node/Express app and reports them to your self-hosted ErrorLens instance.

Fire-and-forget: a reporting failure (network blip, ErrorLens instance down) never throws, blocks, or crashes the app it's protecting.

Install

npm install errorlens-express

Usage

import { init, expressErrorHandler } from 'errorlens-express';

init({
  apiKey: 'el_your_project_api_key',
  url: 'https://errors.yourcompany.com',
});

// after all your routes
app.use(expressErrorHandler());

That's it. init() also attaches process.on('uncaughtException') and process.on('unhandledRejection') handlers automatically, so crashes outside the Express request/response cycle are captured too.

What gets captured

For every error: message, stack trace, the file and line it originated from, a snippet of the surrounding source code (read directly off disk — this is what makes ErrorLens's AI root-cause analysis accurate instead of guessing), and your environment (NODE_ENV by default).

API

init(options)

| Option | Required | Default | Description | |---|---|---|---| | apiKey | yes | — | The API key for this project, from ErrorLens's admin API | | url | yes | — | Your self-hosted ErrorLens instance's base URL | | environment | no | process.env.NODE_ENV | Tag reported errors with an environment | | captureUncaughtExceptions | no | true | Set false to opt out of the global handler | | captureUnhandledRejections | no | true | Set false to opt out of the global handler |

expressErrorHandler()

Returns Express error-handling middleware. Mount it after all your routes.

captureException(error)

Manually report an error, e.g. inside a catch block:

try {
  await riskyThing();
} catch (error) {
  captureException(error);
}

Requirements

Node.js 18+ (uses the native fetch API). ES Modules only.

Built & Maintained By

Manish Dash Sharma — Senior Software Engineer

Architecting AI-powered systems that scale. From GenAI integrations to full-stack solutions — turning complex problems into elegant code.

License

MIT © Manish Dash Sharma