09/03/2026 updated
100 % available
Web dev, payment integration & API automation
Seoul, South Korea
Worldwide
Application Programming Interfaces (APIs)Web DevelopmentE-CommercePayment GatewaySystems IntegrationWeb Application DevelopmentWeb ServicesWebDevWooCommerceWebhooks
I build and fix production web services: payment integration, subscription billing, API automation, and WordPress/WooCommerce work.
Recent work:
- Japanese e-commerce site (WooCommerce): applied 3-D Secure with the payment gateway, upgraded the payment plugin, and delivered a security report. Completed and accepted by the client.
- Web service for a Korean startup: built the payment and recurring-subscription flow end to end, delivered in three milestones.
- My own SaaS (TubeUp, tubeup.kr): a video tool with paying subscribers, so I handle card billing, credit accounting, refunds and failed payments in production, not just in demos.
- VeloDesk (velodesk.co.kr): lead capture and follow-up automation for small businesses, built on Firebase Cloud Functions and Firestore.
Stack and tools: Node.js, Python, Flask, PHP, WordPress, WooCommerce, React, REST APIs, webhooks, Firebase (Auth, Firestore, Cloud Functions), Google Cloud Run, Docker, PostgreSQL, MySQL, Playwright and Selenium automation, web scraping, Chrome extensions, Stripe and PayPal integration, Electron desktop builds for Windows and macOS.
Certified: Python (Level 1, 100%), JavaScript (Level 1), WordPress (Level 1).
How I work: I confirm the exact scope before writing code, ship in milestones you can check, and verify on the live site before calling anything done. I write in clear English and reply within one business day.
Experience
Professional experience0 - 5 years
Freelancer since2026
Languages
EnglishFluentKoreanNative speaker
Project history
Built and operate VeloDesk (velodesk.co.kr), a lead capture and follow-up automation service for small businesses.
Landing pages plus a form-to-database pipeline on Firebase (Cloud Functions, Firestore), notifying the owner the moment an inquiry arrives.
Automated follow-up reminders so no inquiry is left unanswered, plus an admin view to track each lead's status.
Ran the ops side too: custom domain, deploy pipeline, and uptime monitoring.
Founder and sole developer of TubeUp (tubeup.kr), a subscription service that turns long videos into short clips.
Built the full stack: Python/Flask on Google Cloud Run, Firebase auth and Firestore, a Chrome extension, and desktop builds for Windows and macOS.
Recurring billing end to end: card subscriptions, credit accounting, refunds, failed-payment handling, and a daily audit job.
Live with 700+ users and paying subscribers, so I handle real invoices and incidents, not demos.