Case Study

First Out: The Fastest Way Off the Tube

Everyone guesses where to stand on the platform. First Out tells you exactly where to position yourself for the quickest exit at every London Underground station -- even underground with no signal.

By Mike Litman • Cultural Capital Labs • 2025-2026
Vanilla JS
Service Worker
stations.json
0 Dependencies
259
Stations
11
Lines
PWA
Offline Support
0
Dependencies

The Problem

Millions of people use the London Underground every day. Every single one of them guesses where to stand on the platform. Should you be at the front of the train? The back? The middle? It depends on the station, the line, and which exit you need -- and there is no reliable, accessible source for this information.

The knowledge exists -- in the heads of seasoned commuters, in scattered forum posts, in muscle memory built over years. But it has never been collected, structured, and made available in a way that is useful at the exact moment you need it -- which is often underground, with no mobile signal.

The Approach

First Out solves one problem perfectly. You search for a station, select your line, and it tells you: front, middle, or back. That is the entire interaction. No accounts. No ads. No unnecessary features. Just the answer.

Station data
→
stations.json
→
Vanilla JS app
→
Service Worker
→
Offline PWA

The critical design decision was building it as a Progressive Web App with a Service Worker. The tube is underground. Signal is unreliable at best, nonexistent at most stations. If the app does not work offline, it does not work where you need it most.

Zero dependencies. No React. No frameworks. Vanilla HTML, CSS, and JavaScript. The entire app, including all 259 stations of data, loads instantly and caches offline. It works underground. It works on the platform. It works the moment you need it.

How It Was Built

1
Data Collection
Compiled platform positioning data for 259 stations across all 11 London Underground lines. Front, middle, or back for every station-line combination, based on exit locations.
2
Data Structure
Structured all data in a single stations.json file -- lightweight, portable, and cacheable. Each station maps to its lines and the optimal carriage position for the fastest exit.
3
Zero-Dependency App
Built the entire app in vanilla HTML, CSS, and JavaScript. No build step. No framework. No npm. Instant load, instant search, instant results. Dark UI designed for underground readability.
4
Offline-First PWA
Service Worker caches the entire app and data on first visit. Works fully offline -- no signal required. Install to home screen for instant access. The app works exactly where you need it: underground.
Technical Architecture
DATA APP OFFLINE DEPLOY [259 Stations] ---> [Vanilla JS] ----> [Service Worker] -> [Netlify] | | | | stations.json 0 dependencies Full cache firstout.app 11 lines Instant search Works offline Static deploy Crowd-verified No build step Home screen PWA manifest

The Result

259
Stations
11
Lines
0
Dependencies
Offline
Always Works

First Out covers the entire London Underground network. Every station. Every line. The answer is always one tap away. The app loads in milliseconds, works offline, and can be installed as a native-feeling app on any phone.

The data is being verified through real travel -- as stations are visited, positioning data is confirmed or corrected. It is a living product that improves with use.

What makes First Out compelling is not the technology. It is the ruthless simplicity. One question. One answer. No friction. No account. No upsell. Just utility, delivered at the exact moment you need it.

The Key Insight

The best apps solve one problem perfectly. First Out does one thing -- and it does it the moment you need it, even underground with no signal.

Most apps try to do too much. First Out is the opposite -- it does one thing, stripped to the essential. You need to know where to stand on the platform. First Out tells you. That is it.

The design constraint shaped the product. Offline-first was not a feature -- it was the fundamental requirement. If it does not work underground, it does not work. That constraint forced simplicity: no API calls, no authentication, no server. Everything local. Everything instant. Everything available.

Lesson Learned
The constraint was the breakthrough. Offline-first was not a feature -- it was the requirement that made everything else simple. Sometimes the limitation is the idea.
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