DecisionPlay

See the game behind every hard decision. Name the players, map their incentives, and find the move that changes the outcome.

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Inspiration

Every hard decision has a game underneath it: a standoff at work, a family plan, a neighborhood dispute, a budget fight. There are players, incentives, and one move that changes the outcome. Game theory (Nash, Schelling, Ostrom, Axelrod) maps that structure brilliantly, and it rarely leaves the textbook. I built DecisionPlay so anyone can see the structure of their own decision in minutes, with their privacy intact.

What it does

DecisionPlay turns a plain-language dilemma into a strategic read:

  • Analyze: describe a standoff and get a Strategic Brief with the players, what each wants, the game type, and the move that changes the outcome. Every assumption is shown.
  • Play: Today's Tension (one new everyday dilemma a day), 177 interactive scenarios, five strategy bots, a strategy tournament, and a Nash Equilibrium Calculator.
  • Learn: Game Theory 101, branching stories, a glossary, and 11 learning paths.
  • Read: 45 strategy briefs on current affairs, health systems, policy, and energy.

Every statistic carries an accuracy label (Verified, Modeled, or Projected) and a source you can check.

Who it helps

  • Students and teachers: Classroom Mode ships three ready-to-run 15 to 20 minute lessons (Prisoner's Dilemma, Ultimatum, The Budget Cut), each with a teacher debrief, a "change this payoff" exercise, and live sessions by join code.
  • People stuck in everyday conflicts: family, roommate, neighbor, and workplace standoffs, where seeing the other side's incentives reveals moves neither side saw.
  • Civic and community groups: policy and budget scenarios show why concentrated costs beat diffuse benefits, and what a fairer decision rule looks like.
  • Anyone who values privacy: no sign-up to start, scenario text is processed in memory and never stored on our servers unless you choose Pro cloud history, DecisionPlay never uses it for training, cookieless analytics, no ads, no data selling.

Guardrails are built in. DecisionPlay is a thinking aid: it will not predict elections, wars, or coups, and its daily streak stays on your device with no dark patterns.

How I built it

  • Web app: React, Vite, and TypeScript on Netlify, with Netlify Functions for the backend and Netlify Blobs for Pro cloud history
  • Native iOS: the same codebase wrapped with Capacitor (bundle com.saebchicago.decisionplay)
  • Monetization: RevenueCat powers DecisionPlay Pro (monthly and annual) with a single "pro" entitlement. Pro keeps your decisions current: private cloud history across devices, Living Game refreshes against a public source you choose, strategic diffs that preserve your saved baseline, and account export and deletion.
  • Analysis layer: LLM-generated Strategic Briefs held to a structured output contract, so every read has consistent sections and visible assumptions
  • Content system: scenarios, briefs, thinker profiles, and learning paths with provenance labels on every statistic

Challenges I ran into

  • Taking an existing web app to a native iOS build that meets App Store review standards
  • Wiring RevenueCat entitlements so Pro adds real depth while the core experience stays open
  • Keeping LLM output honest with structured contracts, visible assumptions, and accuracy labels
  • Handling sensitive topics responsibly, with multiple analytical lenses and clear limits on what the app will claim

Accomplishments that I'm proud of

  • A deep library, live on decisionplay.app/impact as of Sep 29, 2026: 177 scenarios, 45 strategy briefs, 24 thinker profiles, and 11 learning paths
  • Classroom-ready lessons a teacher can run the same day
  • A privacy posture that holds up: text stays off our servers unless you opt into Pro cloud history, no ads, no data selling

What I learned

  • The best subscription gives returning users continuity and depth on top of an open core
  • RevenueCat removes most of the StoreKit plumbing, which let me spend my time on the product
  • Trust features (labels, sources, privacy defaults) are core product features

What's next for DecisionPlay

  • App Store launch and feedback from the first Pro subscribers
  • Pilots with teachers and community groups using Classroom Mode and team rooms
  • News article analysis: paste a URL and see the strategic dynamics

DecisionPlay provides educational analysis only, not legal, medical, or financial advice.

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