Yellow Sun Systems

Superpowers for everyday people.

We build focused, thoughtful apps that help ordinary people do extraordinary things — tools that feel like superpowers.

Planning & Decisions

Monaco

Monte Carlo retirement planning — run thousands of trials and get plain-English answers to when you can retire, the best Roth conversion strategy, and Social Security claim timing.

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Retire Slider

One-screen retirement planner — type your net worth, slide your annual spending, and watch your 30-year risk of ruin update live.

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House Ranker

Paste a Zillow URL and get AI-scored rankings for your home shortlist, with customizable factors and photos classified by room type.

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Creative Tools

DreamZone

A personal dream journal with AI-powered analysis — capture your dreams, discover patterns, and unlock insights from your subconscious.

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The Writing Sessions

A focused writing tool to help you build a consistent creative writing habit and push past the blank page.

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Quill

⚗ Prototype

An AI-centric spreadsheet with a flexible canvas — floating rich docs, images, shapes, slides, and reusable grid snippets all in one place.

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Health & Fitness

Step Right

An iPhone step tracker that turns walking into a game — animated ring, streaks, milestones, and confetti when you hit your goal. Free, no ads.

More Info → Available on the App Store

Games

Solitaire

Classic Klondike solitaire in your browser — clean, no ads, no sign-up, with a Coach Mode to sharpen your game.

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Also available for iPhone on the App Store.

FPS Trainer

Never played a shooter? Start here. Fourteen lessons take you from “how do I look around?” to clearing a building under fire, plus timed aim drills that track your progress.

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Hogan's Alley

A reaction-time and marksmanship trainer modelled on the FBI Academy facility — a physically modelled hold, shoot / don't-shoot judgment, and timing honest enough to trust.

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Dungeon Crawler Carnage

A first-person dungeon shooter roguelite — eight procedural floors, stacking boons, loot, and bosses, with a Coach Mode for first-time shooter players.

Play → More Info →

Private Apps

These apps are for family and close friends.