Shady Baby

Permission Slip

Fri, 01 May 2026 00:00:00 +0000

I build ad tech for a living. I also have a baby. So I searched Google Play for "baby tracker", "pregnancy tracker", "contraction timer", "baby sleep white noise", "baby monitor", "breastfeeding pumping tracker", "baby milestone", and a few more. Took the top results by install count. Decompiled them with jadx. Scanned every one for tracking SDKs, ad networks, and permission requests.

56 apps on the list. 46 survived decompilation. 472 million combined installs. The scanning was automated: grep for SDK packages, tracker domains, pre-consent initialization, and child data fields near analytics calls.

GPS Dies at the Supermarket Door

Wed, 29 Apr 2026 00:00:00 +0000

A stroller walk does not end at the supermarket door. The route planner gets you to the entrance, congratulates itself, and stops. The parent still has to find milk, diapers, a checkout lane wide enough for a stroller, and an exit that does not require reversing through a pyramid of seasonal snacks.

So I built the smallest indoor audit rig I could: an Android phone in my pocket, recording Bluetooth, WiFi, GPS, magnetometer, accelerometer, audio level, ultrasonic spectrum, and step cadence every 2-3 seconds. I walked three Danish supermarkets. Four walks total, two in pocket, two in hand.

We Removed the Money From an Ad Network. It Collapsed to 200 Lines of JavaScript.

Wed, 22 Apr 2026 00:00:00 +0000

We removed the money from an ad network. The entire system collapsed to 200 lines of JavaScript.

I build ad tech for a living: ad servers, auction systems, impression forecasting. My side project is a stroller route planner that finds shade for babies. It has zero ads. Then I noticed we have 270K cafes in the tile data.

A cafe in Nørrebro doesn't need programmatic advertising. They need the parent walking past to know they have 15% off today. That's it. A proximity check and a notification. But the tools that exist (Google Ads, Meta, delivery platforms) are built for a different scale and a different problem. A cafe owner shouldn't need to learn keyword bidding to tell someone 100 meters away they have a discount.

We Replaced Our Routing Engine With a Neural Network That Has Never Seen a Map

Fri, 17 Apr 2026 00:00:00 +0000

We fed GPT-2 100,000 walking routes as token sequences. It learned Copenhagen's geography without ever seeing a map. Then we put it in your browser.

Try it yourself -- click two points on the map and watch a neural network hallucinate a walking route in real time. No server. 27MB of weights running on your CPU via WebAssembly. Weights on HuggingFace.

8Mparameters

100ktraining routes

~7mgrid resolution

~$10Colab A100 rental

Valhalla needs a road graph, tile data, costing models, a C++ codebase, and a server. We replaced all of that with 8 million floating-point numbers. It doesn't follow roads. But it knows where Copenhagen is.

We Let an AI Argue With Itself About Pentagons for 12 Hours

Thu, 09 Apr 2026 00:00:00 +0000

Our round-trip walk generator was embarrassing. You'd ask for a 30-minute stroller walk and it would drop three points in a triangle, send them to Valhalla, and pray. The result: walks that took 45 minutes, routes that retraced the same street, and a loop through Bella Center that was basically a straight line walked twice.

How We Handled Our Exponential Growth by Moving the Problem to the User

Mon, 06 Apr 2026 00:00:00 +0000

When I founded Shady Baby, I had a simple vision: no baby should ever have sun in their face during a stroll. What I didn't anticipate was how complicated it gets when you try to do that across 44 countries while also checking the wind.

Today our CTO shipped what we believe is the most significant architectural change in the company's history. We moved the entire data pipeline into the user's browser. Their CPU. Their RAM. Their electricity bill.