About Serhii Malyshev

Why I Built Env-Sentinel

Working extensively with microservice-based projects, I've seen firsthand how environment variables are the main way of configuration. With many configs come many opportunities for mistakes—and I've experienced them firsthand, spending countless hours debugging configuration issues. As a Tech Lead and Team Lead, I needed to keep configurations safe and reliable while providing better Developer Experience (DX). Developers aren't always great at documenting, so I added documentation generation to help teams stay aligned. Existing tools didn't cover all the needs I had, and they weren't updated frequently enough. I needed something fast that had everything I required—so I built my own tool.

Here's the thing: when you're juggling dozens of microservices, each with its own set of env vars, chaos happens. Fast. Missing DATABASE_URL? Production's down. Typo in API_KEY? Good luck debugging that at 3 AM. I've been there. More times than I care to admit, honestly.

So I built something that does what I actually needed:

• Catches errors early—before they hit production. Because nobody wants to debug config issues at midnight.
• Finds typos automatically—you know, the ones that slip through code reviews and break everything.
• Generates docs—because developers hate writing documentation, but we all need it.
• Plays nice with CI/CD—fits into your workflow without being annoying.

Existing tools? They were either too simple, way too complicated, or just... abandoned. So I built the thing I wish existed five years ago. I wrote about the whole mess in an article for JavaScript in Plain English—the story of how I went from env chaos to something that actually works. If you want more details, check out my posts on catching errors early and common .env mistakes.

Technical Background & Experience

25+ years in IT. 15+ of those building web apps. I've touched everything from tiny startups to massive enterprise systems—websites, social networks, CMS platforms, CRMs, ERPs. You name it, I've probably worked on something like it.

Enterprise Experience

Spent some time at SugarCRM—you know, that CRM system millions of people use? Yeah, that one. Working on something at that scale teaches you things. Like how configuration mistakes can bring down entire systems. And how important it is to get it right the first time, because rolling back isn't always an option.

These days I'm a Tech Lead on an enterprise platform. I own multiple services end-to-end—architecture, frontend, infrastructure, the whole mess. And that's where I really learned what a pain env vars can be when you're managing them across dozens of microservices. That frustration? That's what Env-Sentinel came from.

Open Source & Community

I review tech books for PacktPub—mostly web dev stuff. Also write and edit for JavaScript in Plain English. And I maintain open source projects. Ran the Yii Debug Toolbar for 5 years—thousands of developers used it. That taught me something important: build tools that solve real problems people actually have. Not theoretical problems. Real ones.

Env-Sentinel follows that same idea. It's built by someone who's been there, debugging config issues at midnight, wondering why production broke when it worked fine locally. Sound familiar?

Technical Expertise

I work with the usual suspects: Node.js, TypeScript, NestJS, React, PostgreSQL, Docker, Kubernetes, AWS. Architecture, microservices, backend stuff, DevOps. But here's what matters more: I know how these pieces fit together in the real world. Especially when configuration goes wrong.

If you're fighting configuration drift, trying to figure out env var best practices, or just want to automate your docs, I've written about all of it. Real experiences, not theory. Also check out my JavaScript in Plain English article on the whole journey.

The Problem We're Solving

Env vars are everywhere in modern apps. And they break everything. Missing variable? Production's down. Typo? Hours wasted debugging. No docs? New team members are lost. It's frustrating. And it happens way too often.

The Real Cost of Configuration Errors

Microservices make it worse. Each service needs 10, 20, maybe 50+ env vars. Multiply that by dozens of services and you're managing hundreds of config values. One typo. One missing variable. One wrong value. Everything breaks.

The 12-Factor App methodology says "store config in env vars." Great advice. But it doesn't tell you how to actually manage them without going insane. That's the gap Env-Sentinel fills.

How Env-Sentinel Helps

Here's what it does:

• Validates everything—catches missing vars and wrong types before deployment. No surprises.
• Lints automatically—finds typos and unsafe patterns. The stuff that slips through code reviews.
• Generates docs—creates documentation from your schema. Always up to date, because it's generated, not written manually.
• Works with CI/CD—runs in your pipeline. Stops broken deployments before they happen.

Want details? Check out the guides on validation, linting, and documentation.

Our Mission

Make env configuration boring. Seriously. No surprises. No midnight debugging sessions hunting down missing variables. Just config that works, validated and documented, so you can forget about it.

Configuration shouldn't be exciting. When it is, something's broken. Env-Sentinel makes env var management predictable and safe—so you can actually build features instead of fixing config disasters.

Solo dev on a side project? Tech lead managing 50+ engineers? Doesn't matter. Env-Sentinel catches errors early, documents everything, and lets you deploy without holding your breath.

Open Source & Community

Env-Sentinel is open source. It's on GitHub. Contributions, issues, feedback—all welcome. After maintaining projects like Yii Debug Toolbar for years, I've learned that community feedback is what makes tools actually useful. Not my ideas. Yours.

Free to use. MIT license. Find a bug? Have an idea? Open an issue. Or submit a PR. Every bit of feedback makes it better.

Also on npm. Install it today. Use it. Break it. Tell me what's wrong with it.

Ready to Get Started?

Tired of debugging production failures caused by missing environment variables? Want to catch configuration errors before they hit production? Stop spending hours hunting down typos in .env files?

The QuickStart Guide shows you how to set up Env-Sentinel in under 5 minutes. You'll learn how to validate environment variables, catch errors early in development, lint your .env files for common mistakes, and automatically generate documentation—all without writing a single line of documentation yourself. No installation required if you use npx, so you can try it right now.

Perfect for developers new to environment variable validation, teams struggling with configuration drift between environments, or anyone who's tired of "it works on my machine" becoming "it's broken in production." The guide covers everything from your first npx env-sentinel lint command to setting up CI/CD validation.

Need more? Check out the full documentation for advanced features like custom validators and schema organization, or browse the blog for real-world examples, best practices, and troubleshooting tips from production environments.