Ultimate Logging Guide for Node.js, Bun, and Next.js SSR in 2025

If you’ve been building Node.js apps for a while, you’ve probably used Winston, Pino, or maybe Bunyan for logging. And they’ve served us well — structured logs, log levels, file transport — all good stuff.

But here’s the thing: logs alone aren’t enough anymore.

Modern applications need more than just lines in the terminal or log files. You need to see logs in a dashboard, filter them, search by word, errors with meta details, get alerts, and sometimes even dig into logs from multiple environments — local, staging, prod — without relying on a third-party cloud provider.

And that’s exactly why Errsole exists.

It’s an open-source logging system built specifically for Node.js. It’s not just a logger — it’s a complete log management tool, with:

• A web-based log viewer
• Alerts (email, Slack)
• Support for structured logging, metadata, and JSON payloads
• Built-in support for Express, Fastify, NestJS, Koa, Hapi, Next.js (SSR)
• Storage flexibility (SQLite, MySQL, Postgres, MongoDB)
• Production-grade performance that beats Elasticsearch and Cloud loggers by 70,000–90,000 RPM
• All self-hosted, no vendor lock-in

Let’s break this down properly and explain why Errsole is different than every other Node.js logger — and why it might be the only logging tool you’ll need.

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1. Built-in Log Viewer That Runs in Your App

With Pino or Winston, you get log lines. If you want to view them visually, you have to set up something like Kibana, Grafana Loki, or a third-party tool like Better Stack or Logtail. That takes time, config, and often… monthly bills.

With Errsole, the log viewer is part of the package.

It runs as a lightweight web dashboard (by default on port 8001), where you can:

• Search logs by keyword, user ID, path, or any custom field
• Filter logs by level (error, warn, debug, info, alert)
• See metadata like HTTP headers, DB queries, request bodies
• View logs in full-screen JSON mode
• Inspect logs across environments and apps

And it’s super easy to embed. Just add the Express proxy middleware and you can serve the log viewer at /errsole inside your own app — no need to open ports or run extra containers.

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2. Instant Setup with Built-in Console Capture

Errsole works out of the box. As soon as you call errsole.initialize(), it starts capturing all logs, including:

• console.log, console.warn, console.error
• Uncaught exceptions
• Unhandled rejections
• Stack traces
• Errors thrown inside async functions or routes

No need to rewrite your existing log statements or wrap everything in custom logic. Errsole handles it all for you.

You can also disable console output, or configure which log levels to capture using collectLogs option in its config.

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3. Blazing Fast Performance (Benchmarks Don’t Lie)

Let’s talk real numbers.

When benchmarking Errsole vs popular setups like Pino + Elasticsearch or Winston + CloudWatch, the difference was massive.

In tests using AWS EC2 instances and a simple Node.js app under K6 load testing, Errsole consistently handled 70,000–90,000 more requests per minute than Elasticsearch-based loggers.

Why?

Because:

• Elasticsearch, CloudWatch, and Better Stack all use HTTP. Logs are sent over the network — which adds latency, risk of log loss, and slowdowns under load.
• Errsole writes to local databases, like SQLite, MySQL, MongoDB, or Postgres. That’s faster, more reliable, and 100% under your control.

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4. Powerful Advanced Logging Features

Errsole isn’t just about catching logs — it helps you understand them deeply.

It supports:

• Log Levels: log, info, warn, error, alert, debug
• Alerts: Send critical logs to Slack or Email with errsole.alert()
• Structured Logs: Attach metadata (like req.body, query params, user session info)
• JSON-friendly view: Inspect logs in a clean, collapsible format
• Search + Filter UI: Find logs by route, level, words, or custom tags

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5. Storage Options for Every Use Case

Errsole doesn’t force you into one database or logging stack. You choose how and where to store your logs.

It supports:

• SQLite for local development, testing, or small apps
• MySQL for shared logs in production APIs
• PostgreSQL for scalable, transactional logging
• MongoDB for flexible, schema-less logs and large-scale data

You can even run multiple apps logging into the same DB, using tablePrefix or collectionPrefix to separate logs by app name.

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6. Runs Anywhere — Local, Server, Docker, Cloud

Whether you’re developing locally, deploying to EC2, running containers, or using serverless platforms, Errsole fits right in.

You can:

• Run it as a standalone app with its own viewer UI
• Mount the dashboard inside your main app at any route
• Use it in dev, staging, or prod — with separate DBs or shared ones
• Use appName, environmentName, serverName to organize logs by source

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7. Works with Your Favorite Frameworks

Errsole integrates smoothly with popular Node.js frameworks:

• Express (zero-config)
• Fastify (full guide available)
• NestJS (supports interceptors, services, DI, etc.)
• Next.js SSR apps (server-side logging with SQLite or MySQL)

It even works as a transport for Winston via winston-errsole, so you can upgrade your existing logger setup without a rewrite.

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8. Safer Than Remote Logging

Let’s be honest — cloud loggers are fast to set up, but they come with risks:

• Privacy issues: Your logs go to someone else’s server
• Downtime risk: If the logging service goes down, your logs vanish
• App crashes: Under high load, HTTP log calls can block or fail
• High cost: You’ll pay per GB or per log line as you scale

With Errsole, none of that happens. Your logs are on your infra, you pay $0/month, and your app stays safe — even under pressure.

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9. Real-World Proof & Developer Stories

Developers have already shared their stories of switching to Errsole:

• One team saw 60% throughput improvement after replacing Better Stack with Errsole
• Another dev caught an error that almost wiped their app’s production data — and Errsole helped them debug it in seconds
• Multiple teams use Errsole daily in Fastify, Next.js, and NestJS apps running at scale

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10. Open Source, Free Forever

Errsole is fully open-source, with permissive licensing, and runs under your full control. You can:

• Fork it
• Self-host it
• Contribute to it

No API limits. No tracking. No hidden costs. Just logs you control, in a viewer you own.

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Final Thoughts

Winston and Pino will give you log lines. Cloud loggers give you dashboards — for a price. But Errsole gives you the best of both worlds:

• Easy to set up
• Fast to scale
• Beautiful to view
• Safe for production
• 100% free and self-hosted

Whether you’re a solo dev building side projects, or a team deploying production microservices, Errsole is the logging tool you didn’t know you needed.

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Ready to get started?
👉 npm install errsole
👉 Visit: https://github.com/errsole/errsole.js