evlog.
Getting Started

Install evlog

Frameworks
Install evlog in your TypeScript project. Supports Nuxt, Next.js, SvelteKit, Hono, Express, Fastify, Elysia, NestJS, and standalone scripts.

evlog supports Nuxt, Next.js, SvelteKit, Nitro, NestJS, and any TypeScript server framework.

Install

pnpm add evlog

Using Agent Skills

If you use an AI assistant (Claude Code, Cursor, etc.), install the evlog skill for guided setup and code review:

Terminal
npx skills add https://www.evlog.dev

Your AI assistant can then help you set up evlog, review your logging patterns, and migrate existing code to wide events. See Agent Skills for details.

Choose Your Framework

After installing the package, follow the setup guide for your framework:

Nuxt

Module with auto-imported useLogger, createError, and parseError.

Next.js

createEvlog() factory with withEvlog() handler wrapper.

SvelteKit

Handle and handleError hooks with event.locals.log.

Nitro

Module for Nitro v2 and v3 with plugin-based hooks.

TanStack Start

Uses Nitro v3 module with async context.

React Router

Middleware with context.get(loggerContext).

NestJS

EvlogModule.forRoot() with global middleware.

Express

Middleware with req.log.

Hono

Middleware with c.get('log').

Fastify

Plugin with request.log.

Elysia

Plugin with log in route context.

Cloudflare Workers

Factory for request-scoped loggers.
See the full Framework Integrations page for a comparison table and all available integrations including Standalone TypeScript, Astro, and Custom Integration.

TypeScript Configuration

evlog ships with full TypeScript type definitions. No additional configuration is required.

evlog requires TypeScript 5.0 or higher for optimal type inference.

Next Steps

  • Quick Start - Learn the core concepts and start using evlog
  • Wide Events - Understand the wide event pattern
  • Adapters - Send logs to Axiom, PostHog, Sentry, and more

Introduction

A structured logging library for TypeScript. Simple logging, wide events, and structured errors, from quick one-liners to comprehensive request-scoped events.

Quick Start

Get up and running with evlog in minutes. Learn the log API, createLogger for wide events, useLogger for requests, and structured errors.