You know that nagging feeling you get right after pushing a big new feature live? It’s a mix of excitement and a low-key, thrumming anxiety. You’ve tested everything, your CI/CD pipeline is a thing of beauty, but in the back of your mind, you’re wondering, “What am I not seeing?”

That was me a few weeks ago. Our APIs were humming along nicely, and our Web Application Firewall (WAF) was doing its job, blocking the obvious junk. But I felt like I was driving with a foggy windshield. Sure, the WAF was stopping bad guys at the door, but what was it actually seeing? Was there a coordinated attack slowly ramping up? Was a new endpoint I just deployed getting hammered in a way I didn’t anticipate?

The logs were there, buried somewhere, but digging through them felt like an archaeological expedition. I didn’t want a history lesson; I wanted a real-time pulse. I wanted to see what was happening, as it was happening.

And that’s how my weekend project was born. I decided to build my own real-time API security monitor—a sort of command center that would give me that at-a-glance peace of mind.

The Bouncer and the Eavesdropper

My first thought was, “Don’t reinvent the wheel.” My WAF is like a diligent bouncer at a club.

It’s checking IDs, turning away troublemakers, and generally keeping the peace. It’s great at its job. The problem wasn’t the bouncer; it was that I couldn’t hear what the bouncer was muttering to himself.

Every block, every challenge, every weird request—the WAF was dutifully noting it down. All I needed to do was listen in. Most modern WAFs have a way to stream their logs out in real-time.

It’s like putting a little microphone on the bouncer’s collar. Instead of waiting for his end-of-shift report, I could hear everything, instantly. This was the first piece of the puzzle.

The Brains of the Operation: My Old Friend, Node.js

So, I had a firehose of log data. Now what? I needed something to catch all this information, make sense of it, and maybe even get a little clever.

For this, I reached for my old friend, Node.js. Why? Because it’s just brilliant at juggling lots of little tasks at once. It’s built for this kind of real-time, event-driven work. The idea was simple:

I’d set up a small Node.js service that would just sit there and listen to the log stream coming from the WAF.

For every log that came in—a blocked SQL injection attempt, a suspicious user agent, a weird pattern of 404 errors from a single IP—my Node service would grab it, take a look, and process it. It wouldn’t just be a dumb pipe; it would be the central nervous system. It could count things, notice patterns, and enrich the data. For example, it could see an IP address and quickly figure out which country it was from, or if it was a known “bad” IP from a threat intelligence list.

Bringing it to Life: The Dashboard

This is the part that really gets me excited. Raw data is useful, but it’s not very inspiring. Staring at a scrolling terminal of JSON isn’t my idea of a good time. I’m a visual person. I need charts. I need graphs. I need big, red, flashy warnings when something is wrong.

So the final piece was a dead-simple, real-time dashboard. My Node.js service, after processing a log, would push the important bits over to a front-end interface.

Suddenly, it wasn’t just a cryptic log entry anymore. It was:

• A map of the world, with little flashes appearing from countries where attacks were originating.
• A timeline graph showing a sudden spike in blocked requests, letting me know someone was trying to scan my site.
• A “Top 10 Blocked IPs” list that updated every few seconds.
• A running tally of the types of attacks being blocked—cross-site scripting, SQL injection, etc.

The first time I saw it work was magical. I deliberately ran a security scanner against my own staging environment, and the dashboard lit up like a Christmas tree. It was like flipping a switch and suddenly seeing in the dark. I wasn’t just relying on a silent guardian anymore; I had a visual heartbeat monitor for my application’s security.

This little project hasn’t replaced my WAF, of course. It’s made it better. It’s given me a window into what it’s doing, turning its silent, thankless work into actionable, immediate intelligence. And that nagging feeling? It’s a lot quieter now. I can finally see what I was missing.

My Weekend Project: Taming the Code Beast with a DIY Maintainability Tool