OpenAI 2026 hackathon

RallyRef

RallyRef turns an Apple Watch and iPhone into a courtside squash referee—keeping score, service, announcements, and video in sync when no official is available.

Solo project by Ying Tang · 0 likes · 0 comments

Archive position — measured, not model output

0 likes on Devpost

2,264 of the 7,856 archived projects have more likes, and 5,592 share exactly 0 — so this project's #6,243 place in the like-ranked listing is a tie-break inside that group, not a ranking.

Projects (log scale)

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Likes on Devpost. ▲ marks this project's group.

Show the figures
LikesProjectsShare of archive
05,59271.2%
11,75822.4%
22853.6%
3–41321.7%
5–9751.0%
10+140.2%
Devpost like counts for all 7,856 archived projects, captured when this archive was built.

Executive Summary

What the company appears to be

RallyRef is a personal project by one developer (Ying Tang) that turns an Apple Watch and iPhone into a courtside squash referee. It supports match creation, scoring, service tracking, announcements, optional video recording, and timeline review — all without requiring an official referee.

What changed

The author describes this as a "personal project" built for practical use in squash training and casual matches where no referee is available. It uses Swift, SwiftUI, and Apple Watch connectivity to implement a cross-device workflow with iPhone as the authoritative source of match state.

Single most important open question

Does RallyRef have any commercial traction or evidence of real-world adoption beyond the author's own testing? The description states no revenue, customers, or usage data exist beyond the demo and personal use case.

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What The Product Actually Is

The description states that RallyRef is a cross-device squash referee tool built for Apple Watch and iPhone. It supports:

  • Match creation with two players, designated Watch Scorer, and best-of-three or five format.
  • Score tracking using official squash rules (11-point games, win-by-two deuce, service handovers).
  • Service box tracking (left/right), Game Ball, Match Ball.
  • Apple Watch as the only manual input surface during play.
  • iPhone as the authoritative source for score, service state, and persistence.
  • Optional video recording of matches with synchronized timeline.
  • Voice announcements played from iPhone.
  • Local storage of match data for review.

The system uses a pure Swift squash rules engine that defines match semantics and produces structured referee events. The UI and connectivity consume these events rather than independently calculating scores.

Evidence Self-reported by the author; no independent verification.

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Positioning & Claim Evolution

The author positions RallyRef as:

  • A tool to replace an official referee in squash matches where one is not available.
  • A solution for players who want to avoid "reaching for a phone" or relying on third parties beside the court.
  • An exploration of how AI (Codex and GPT-5.6) can be used to define rules, implement systems, and build tests around match logic.

The project evolved from a personal frustration with referee-less squash matches into a technical experiment using AI-assisted development tools.

Evidence Self-reported claims about intent and positioning; no evidence of market traction or external validation.

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Target Customer & ICP

The description states that RallyRef targets:

  • Players in squash training and casual matches.
  • Users who want to avoid needing an official referee.
  • People who already own Apple Watch and iPhone devices.

It is not described as targeting professional leagues, tournaments, or commercial sports organizations. The focus appears to be on casual and recreational squash players, particularly those who play without referees.

Evidence Self-reported; no evidence of customer segmentation or specific buyer personas.

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Business Model & Pricing Evidence

There is no evidence in the description of a business model or pricing structure. The project is described as a personal endeavor, not a commercial product.

The author mentions that it was submitted to an OpenAI hackathon and is focused on building a controlled MVP for squash.

Evidence Not evidenced.

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Technical & Delivery Signals

RallyRef is built using:

  • Swift and SwiftUI
  • WatchConnectivity API for communication between devices
  • AVFoundation and Photos integration for optional video recording
  • Local persistence for match data, timelines, player profiles
  • XCTest for testing match rules, synchronization, recovery behavior

The architecture is described as:

  • Having iPhone as the single source of truth
  • Apple Watch submitting intent, iPhone validating and persisting
  • Voice playback from iPhone to avoid online requests during rallies
  • Use of AI (Codex/GPT-5.6) for rule modeling, UI design, and test coverage

Evidence Self-reported technical details; no evidence of production deployment or scalability.

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Traction & Maturity Signals

There is no evidence of traction, revenue, customers, or adoption beyond the author’s own testing and demo setup.

The project is described as a personal MVP, submitted to a hackathon, and focused on controlled squash simulations rather than real-world usage.

Evidence Not evidenced.

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Competitive Context

The description does not mention any existing competitors or similar tools in the market. It focuses solely on the author’s own solution for referee-less squash matches.

It is unclear whether there are other apps or systems that attempt to automate squash scoring or provide referee-like functionality.

Evidence Not evidenced.

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Key Risks & Red Flags

  • No commercial traction: The project is described as a personal experiment with no evidence of real-world adoption.
  • Limited scope: Only supports squash, and only on Apple devices.
  • Single-person team: No indication of scaling or support structure.
  • AI dependency: Relies heavily on Codex/GPT-5.6 for development; unclear if this is sustainable or scalable.
  • No monetization strategy: No mention of pricing, licensing, or revenue model.

Inference The lack of any commercial or user-facing data raises concerns about viability as a product or business.

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Diligence Questions To Ask The Founders

  1. What is the actual usage or feedback from real squash players?
  2. Are there plans to expand beyond squash or to other sports?
  3. How does the system handle offline scenarios or connectivity issues in real matches?
  4. Is there any intention to commercialize this product, and if so, what would that look like?
  5. What are the limitations of using AI-assisted development for such a precise and rule-based system?

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Investment/Partnership Verdict

Not evidenced.

There is no evidence of revenue, customers, or traction beyond the author’s own testing and demo. The project is described as a personal MVP submitted to a hackathon.

The author does not indicate any intention to commercialize or scale the product at this time.

This appears to be an early-stage idea with no clear path to market traction or investment-ready maturity.

Confidence Low — based entirely on self-reported description.

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Source

Submitted to the OpenAI 2026 hackathon on Devpost. Project home on DevPost.

The analysis above was generated by a language model from the project's own one-line description. It is not independent research and contains no verified traction, revenue or customer data.