Yellow Sun Systems

Learn. Create.
Improve.

Focused technology, individualized feedback.

Yellow Sun Systems creates software and publishing tools that help people learn, create, and improve through individualized AI feedback.

We build focused products with a simple philosophy: use technology where it adds real value, keep the experience straightforward, and avoid unnecessary complexity.

Explore our work Talk to a human
Monaco retirement plan dashboard
01 Monaco
DreamZone dream journal
02 DreamZone
Vibe Wrangler task board
03 Vibe Wrangler
Real value Straightforward experiences Focused products No needless complexity

Three divisions

One studio.
Many ways to tell a story.

01 Yellow Sun Books Our independent publishing imprint, working with a small number of authors and books we believe in. Meet the imprint 02 Apps Focused tools, creative experiments, and thoughtfully made games. Explore the apps
03 Photography Two simple services for photographers to present their best work and proof photographs with clients. Yellow Sun PortfoliosShowcase your best work Yellow Sun GalleriesProof photos with clients Free for photographers for a limited time. Always free for the public and clients.

Apps division

Tools for real life.
Games for the rest of it.

One small studio, a growing family of practical tools, creative experiments, and thoughtfully made games.

01

Planning & Decisions

See the path ahead

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.

Go to app → More Info →

Retire Slider

One-screen retirement planner — type your net worth, slide your annual spending, and watch your 30-year risk of ruin update live. Free, no ads, no log in, and your numbers never leave your device.

  • Free
  • No Ads
  • No Log In
  • Private
Go to app → More Info →

Also available for iPhone on the App Store.

House Ranker

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

Go to app → More Info →

Media Tracker

Keep track of the TV you have watched, see every aired episode you still need to catch, and share a viewing list with people you trust.

Go to app → More Info →

02

Creative Tools

Make room for ideas

DreamZone

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

Go to app → More Info →

The Writing Sessions

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

Go to app → More Info →

Pencil

Pick a picture, press Draw, and watch a pencil sketch onto it stroke by stroke — building on what is already there, so an ace of clubs becomes a tree and a ruled page becomes a sea.

  • Free
  • No Log In
  • Private
Go to app → More Info →

Quill

⚗ Prototype

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

Go to app → More Info →

03

Developer Tools

Build with confidence

Vibe Wrangler

An open-source task board that hands work to a coding agent on your machine — Claude Code, OpenAI Codex, or Grok Build. Runs locally; your code never leaves your computer.

  • Open Source
  • Local
  • Private
GitHub → More Info →

04

Health & Fitness

Move a little more

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.

App Store → More Info →

05

Games

Play with purpose

Solitaire

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

Go to app → More Info →

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.

Go to app → More Info →

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.

Go to app → More Info →

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 →

06

Private Apps

For friends & family

These apps are for family and close friends.