Makiko Ohashi

Full-stack Web Developer

TypeScript / React / Next.js / Node.js

Formerly worked in international trade operations, where I saw firsthand how operational workflows and legacy systems affect day-to-day business.

I now build and maintain production web applications for clients, while developing my own products around problems I have encountered in real-world operations.

Professional Experience

Production web application development, maintenance, and third-party integrations for SaaS and business systems.

SaaS & Business Systems — Ongoing feature development, maintenance, authentication, database operations, and production improvements for React / TypeScript applications.
Payment Integrations — Implementation and maintenance of payment flows using Stripe and PayPal, including webhooks and production operations.
Third-party Integrations — Integration of external services including Zoom Meeting SDK, LINE, Shopify, and AI APIs.
Backend & Infrastructure — API and data-layer development using Node.js, Fastify, PostgreSQL, Supabase, Cloudflare Workers, and D1.
Shopify Development — Store builds, theme customization, application development, and operational improvements for merchants.

Products

Shopify App / iOS apps / LINE learning service

Inbound Tracking

Origin:Small import merchants struggle to track in-transit inventory; existing ERP tools are too heavy for their scale.

Purpose:Built a Shopify app to automatically track shipments using trade documents and sync inventory on warehouse arrival.

Shopify app for merchants importing goods.

Tracks in-transit inventory using trade documents,

syncs to Shopify on warehouse arrival.

Live on App Store. Featured on TSUN.ec.

Remix Node.js Supabase TypeScript

GitHub Launch App

Pocket Shiroiro - iOS Bookkeeping App

A lightweight bookkeeping app for Japanese sole proprietors.

Built to make white-tax-return bookkeeping simple: users can record income and expenses, categorize transactions, and save their data directly to their own Notion database.

The app focuses on practical solo-business workflows rather than full accounting software complexity.

Available on the App Store. Includes a Notion template for saving bookkeeping data.

SwiftUI Notion API Cloudflare Workers StoreKit

App Store Notion Template

WAKARUMADE - iOS Math Learning App

A comprehension-first math learning app now available on iOS.

Built to help children understand step-by-step reasoning, not just memorize answers.

The native iOS version uses on-device OCR and a teacher-style chat flow to turn printed math problems into guided learning conversations.

Started as a solo project for Hack This Fall and evolved through rapid iteration with real user feedback. The app adjusts difficulty in real time based on student performance.

Available on the App Store and on the landing page. Built for Hack This Fall.

🏆 Selected for Hacker House and Demo Day as one of the top finalist projects from the month-long hackathon.

SwiftUI Supabase Gemini

App Store Landing Page GitHub

More Projects

Additional apps and small tools I've built across web, iOS, Shopify, and business workflows.

View all projects on KIMA →

Deterministic Forecasting Backend (Hackathon Project)

Backend-only forecasting prototype that separates deterministic demand calculations from AI-generated explanations.

This section focuses on backend design experiments — a concise log of architecture and reproducibility checks.

GitHub Demo Video Certificates

Ruidaichan – AI-to-PDF Math Worksheet Generator (iOS + Server)

iOS-native app that generates printable A4 math worksheets from photographed problems.

Key features:

Free-tier quota enforcement with Redis (monthly caps, atomic Lua)
Privacy-first design (no image retention, minimal identifiers)
Designed to pass App Store review with minimal UX friction

Status: Available on the App Store

App Store GitHub (iOS App) GitHub (Server)

MentorHQ – AI Learning OS (Hackathon Project)

AI-powered learning workspace that builds a learner model from observations made during study sessions, rather than simply evaluating correct and incorrect answers.

Key features:

Observation-first learner modeling
AI Coach Team (Reading / Memory / Pattern / Review)
Daily Review and Tomorrow Plan generation
Optional learner chat that also becomes part of the learner model

Built with Next.js, React, TypeScript, Firestore, and Gemini.

Status: Built for Findy AI Hackathon 2026.

Live Demo GitHub Demo Video Proto Pedia

Coaching Company Ops (Hackathon Project)

AI coaching product for the Japanese Management Operations Supervisor Exam, paired with a company-side operations layer that reviews learner progress and decides when to adjust plans or escalate.

Built as a lightweight product on Cloudflare Pages and Workers, with Supabase for question/session data and Airia for company-side decision workflows.

Explored how to separate learner-facing coaching from operational intelligence while making AI-run company decisions visible in the UI.

Live Demo GitHub Demo Video DevPost Airia Agent

Trade Shelf Agent (Hackathon Project)

AI operational assistant for trade and logistics workflows, built to organize shipment, invoice, and trade-document states while handling ambiguous operational inquiries from sales teams.

Designed around relationship resolution across Shipment / Invoice / SI records, with Slack and web inputs feeding a unified workflow layer backed by Azure OpenAI.

Explored human-in-the-loop approvals, activity trace design, and auditability patterns for operational AI systems. Built for Microsoft Agent Hackathon 2026.

GitHub Live Demo Demo Video Zenn Article

Natural Language Workflow Automation (Hackathon Project)

Explored natural-language-driven workflow automation for operational tasks.

Learned the limits of language interfaces in multi-step business processes.

Did not continue as a backend-first system.

GitHub Demo Video Certificate

Stable Difficulty Generation Engine (Hackathon Project)

Evaluation-first AI generation demo that audits and controls inference questions across difficulty and reasoning dimensions.

Difficulty axes: L / S / A / R

States: Explicit accept / soft-accept / reject

Built for DigitalOcean Hackathon

GitHub Live Demo Demo Video DevPost

Audit Risk Forecast Tracker (Hackathon Project)

Simulates tax audit trigger questions from spreadsheet-based bookkeeping data using Gemini.

Infra: Gemini (reasoning) + Google Sheets (source of truth) + Firebase (non-authoritative cache), with demo/prod isolation

Built for Gemini3 Hackathon

GitHub Live Demo Demo Video DevPost

Pencil Stuck Marker (Hackathon Project)

Behavior-aware AI intervention system for pen-based learning on iPad.

Detects hesitation patterns and triggers optional, non-solution nudges without content understanding.

Signals: Stall time / Write–erase loops

States: Observe / Suggest / Withdraw

Infra: Swift + Vision Agents + Python (FastAPI) + Gemini

Built for WeMakeDevs Vision Hackathon

GitHub Demo Video Certificate

Shopify Development

Developed Shopify stores for small businesses, including full store builds, theme customization, and feature improvements.

Shopify Liquid

Shopify Partner Account

Skills

Frontend

React / Next.js / Remix / TypeScript / SwiftUI

Backend & Data

Node.js / Fastify / Supabase / PostgreSQL / Cloudflare Workers / D1

Integrations

Stripe / PayPal / Shopify API / Zoom Meeting SDK / LINE API / Notion API / Gemini API

Development & Operations

GitHub Actions / Vercel / AWS Amplify / Sentry

About

I build and maintain production web applications, with a focus on practical business workflows, integrations, and lightweight systems.