Y/ONE

Independent product engineering studio · Seoul / remote

Software for the hard parts.

We help product teams ship complex React/TypeScript interfaces, AI workflows, and integrations when the hard part is unclear — as an independent practice based in Seoul.

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  • React / TypeScript
  • Product + engineering
  • Experience since 2020

01 Services

What we build

We work on the parts of a product where interaction, state, and technical constraints meet.

  1. 01

    Complex product interfaces

    React and TypeScript interfaces for SaaS products, editors, and state-heavy workflows.

    • Product UI and editor flows
    • State-management boundaries and component systems
    • Frontend architecture and incremental refactors
  2. 02

    AI workflow tools

    Operator-facing internal tools that turn repeatable work into a visible, reviewable workflow.

    • APIs, durable jobs, and runner steps
    • React operator consoles and review flow
    • Policy or quality gates
  3. 03

    Web3 product interfaces

    Clear product flows for wallets, signing, transaction status, and cross-chain interactions.

    • Next.js interfaces and wallet states
    • Signing flows, asset movement, and status/error states
    • Scoped integrations or prototypes

02 Pricing

Clear starting points

Every engagement is scoped around the problem, constraints, and the outcome that needs to be true. These are starting points for focused work.

  1. 01

    Product / AX discovery

    Problem framing, workflow review, and an implementation path for a focused product or internal-tool decision.

    From $1,500
  2. 02

    Product interface sprint

    A focused React/TypeScript sprint for a complex workflow, state-heavy screen, or product UI improvement.

    From $3,000
  3. 03

    AI workflow prototype

    An operator-facing workflow prototype with the integration, review surface, and quality gates needed to test it.

    From $5,000
  4. 04

    Longer product engagement

    Multi-sprint product development, integrations, or operating improvements shaped around a shared delivery plan.

    Scoped together

Not sure which engagement fits? Chat on Telegram with the product, the difficult part, and the outcome you need.

03 Products

Products we make

Tools for making music and making room for a daily pause.

  1. Public implementationTypeScript · Fastify · BullMQ · PostgreSQL · React

    PatchPilot

    A source-available ticket-to-pull-request platform with durable jobs, policy gates, a runner boundary, and a React operations console for observing, retrying, and reviewing work.

  2. Released appiOS · Web · Audio synthesis · Offline-first

    Musickit

    A web and iOS app delivering 20+ interactive music tools — pitch slides, rhythm makers, and chord instruments — synthesised on-device with no tracking.

  3. Released appiOS · Screen Time API · SwiftUI

    Pause & Pray

    An iOS app that intercepts the moment before a blocked app opens, presents a short Scripture and prayer, then releases the app — using Screen Time controls with no tracking or account.

04 Experience

Experience across product systems

Our experience spans editor products, electronic contracts, AI-assisted workflows, and Web3 product flows.

Experience history

Role and scope descriptions are self-reported professional history.

  1. Independent Product Engineer

    AI-assisted analytics and workflow automation for advertising and renewable-energy projects.

  2. Strobe Finance

    Software Engineer

    Frontend development for an XRPL money-market product and cross-chain product flows.

    Visit Strobe Finance

  3. Modusign

    Frontend Engineer

    Electronic-contract product and editor/frontend development.

    Visit Modusign

  4. MIRIDIH

    Frontend Engineer

    MiriCanvas editor and collaboration-workspace features.

    Visit MiriCanvas

05 Process

A clear path from problem to handoff

The work moves in reviewable steps, with the product and technical boundary visible throughout.

  1. 01

    Frame

    Goals, constraints, evidence, and acceptance criteria.

    OutputA scoped brief.

  2. 02

    Shape

    User flow, technical boundary, and delivery slices.

    OutputA reviewable plan.

  3. 03

    Build

    Working increments with reviewable code and visible progress.

    OutputUsable software.

  4. 04

    Harden

    Accessibility, responsive behavior, tests, performance, and handoff.

    OutputA dependable release candidate and handoff.

06 Research & Community

Beyond the product

Talks and mentoring by our founder, Juyeong Byeon, across the Web3 ecosystem.

  • Axelar Research Collective · Korea

    Speaker · November 2025. Listed in the ARC Korea showcase agenda as a Strobe Finance software engineer presenting in the Axelar Ecosystem Session.

  • XRPL Korea Hackathon

    Mentor · 2025. Joined an XRPL Korea hackathon as a mentor, meeting builders and discussing projects using technologies in the XRPL ecosystem.

07 Contact

Have a product problem worth making simpler?

Send a short note about the product, the difficult part, and what needs to be true when the work is done.

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Y/ONE is an independent product engineering practice. We build software for the hard parts.