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rootnine

Software studio · Seoul

rootnine

I design and build web and mobile products.

Work

What I have built

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Capabilities

What I cover

01

Product design

It starts with deciding what to build. User roles, the permission structure, the data model, and the screen flow go into a document before any code gets written.

02

Web and mobile

Web alongside iOS and Android. I have run a single product across three surfaces at the same time.

03

Backend and infrastructure

Database schemas and access policies, server functions, and scheduled pipelines. Permission and data rules are enforced in the database, not in the application.

04

Release and operations

Getting through App Store, Google Play, and ONE Store review, pushing urgent fixes over a self-hosted channel, and tracking the running system through audit logs.

How I work

How I work

01

Push the rules down to the database

Permission checks do not end at conditional rendering. They are re-verified in database policies and server functions, so bypassing the client does not open the data.

02

Do not trust what cannot be measured

Whether it is focus minutes or beat error, a number reported by the client is not taken at face value. The server recomputes it, or it gets recorded and cross-checked for real.

03

Leave the reasoning behind decisions

Why this choice, why this value — it goes in a document. When something goes wrong, the retrospective becomes policy so the same mistake does not repeat.

04

Never design against the user

No dark patterns, granular consent, and browsing without an account. Accessibility is not something bolted on at the end.