Hello, I'm Juanito. I'm a software engineer.

I love solving real problems via programming and being useful to other people. I read slowly, think slowly, and learning to think rigorously and be meticulous. I love food and enjoy cooking after work. I spend spare time . , enjoy attending and .


Current Activities

I am a backend engineer helping expand globally. My work involves new features and bug fixes for admin products, local payment methods, maintain customer-facing GraphQL API endpoints, internal wiki and documentations, automation for team collaborations, and improve test suite stability.

I help maintain by triaging issues, shipping news translations, and site deployment.

Past Activities


Completed three Data Migrations in a timely fashion for company acquisitions. Extract, load, transform data from external into Cookpad. Develop a progress report for migration, a retry mechanism for failures. Minimum overhead and zero downtime. Programmatically check data integrity post migration. Acquired site URI redirections. Migrate legacy password authentication to secure implementation. Assets migration to Amazon S3. Just In Time migration for active users. Gave a .


Deliver high-quality software and bring new products to market for clients by focusing on Minimum Viable Products, iterating in small steps, adjust based on feedback. Practice Test-Driven Development, Continuous Integration, and other Agile practices to ensure the quality. Build and deploy systems for end-user use (mostly Heroku). Refactor and maintain legacy system. Build internal application and tools. Extract existing parts of application into Open Source Libraries. Give back to the community by contributing to Open Source. Share learnings on engineering blog.

Other Activities

, GitHub Patchwork, and .

About me

I've been an Electronics engineer and . I grew up in Taiwan. I went to universities in Taipei, Taiwan and Leuven, Belgium. Moved to Tokyo in 2017. I currently live in Ebisu, Tokyo.

I speak English, Mandarin, Taiwanese, and write in Traditional Chinese natively. I could also write in Simplified Chinese. I am learning Japanese. I have learned Spanish, French, Dutch for short period of time before.

Sorry I do not have Facebook, Instagram, and Linkedin accounts.

Juanito Fatas?

My name suggests Spanish or Filipino, but it's given by a friend from . Because my real last name pronounced similar to Juan in Spanish. My friend and I became close, so they called me Juanito. Fatas is inherited from the friend. I use this name for too long, it became my identity on the internet.


My main interests include spending time researching what food to eat, programming things that helps people or automates my life, reading things on the internet, traveling, cooking, listening to music and , Japan and its culture, connecting people at conference events, thinking about how to be more kind, warm, supportive when working with others, and appreciating the small pleasures of life.

My favorite, but not mastered yet, programming languages are Lisp-Family programming languages: Scheme and Common Lisp. My favorite food is Sushi. My favorite city is Kyoto, Japan. My favorite websites are Twitter and Wikipedia.

What am I doing now?

Please see my now page.


Need to contact me? My email address is me@ this domain (please do not spam me). Feel free to ask me anything. I read all my emails, but if I don't reply after a week, feel free to send me a reminder. If you know my phone number please don't use it. I much prefer email. You could also send me a direct message on Twitter.