Jason Sebastian

Designer & developer, Jakarta

Giving structure to a daydream.

I'm Jason. I design interfaces, build them, then put them on the internet myself, down to the DNS records.

See the workLet's work together

François Lemoyne, Apotheosis of Hercules, 1733–36, Salon d'Hercule, VersaillesAbraham Mignon, Flowers in a Metal Vase, c. 1670, Mauritshuis, The Hague

I

On the wall

Paramita home screen with the day's verse and tonight's practice
Paramita meditation screen, a pixel art room with a timer
Paramita reader showing the Karaniya Metta Sutta in Pali

Wet paint, still in progress

Paramita, 2026

Flutter, Go, PostgreSQL, Redis, Astro

A practice app for Indonesian Buddhists. Paritta with Pali and meaning side by side, meditation, the uposatha calendar, and vihara communities. Free, no ads, and it keeps working without internet. It's also my thesis.

  • UI, UX and brand, from the first Figma frame
  • System architecture: offline-first sync, SQLite on the phone, a queue back to a Go server
  • Part of the code, and the call on every dependency
  • Staging, production and the release flow

How it's builtNot vibecoded. I make the design and architecture calls and write part of the code. AI coding agents do much of the implementation, and I cross-check what they write and test on my own phone before it ships.

paramita.appJoin the test

terminal.ai.id showing a BRPT.JK chart, Indonesian market news, macro data and a watchlist

Wet paint, still in progress

terminal.ai.id, 2026

TypeScript, Next.js, Express, SQLite, Docker, Caddy

A market terminal for the Indonesian stock exchange. It started as a fork of OpenTerminal, an open source project built for US markets. I added everything IDX: broker summaries, a conviction score, macro data, a Telegram bot, and passkey sign-in.

/q BBCA
price, signals, broker flow
/macro
Bank Indonesia, IMF, World Bank
/portfolio
holdings, with signals on each
/watch
price alerts
/invite
one-time link for a subscriber

terminal.ai.idOpenTerminal

IDPlay website homepage

IDPlay

Figma

Customer-facing website for an internet service provider, designed as the project's UI/UX designer.

Live site

Studium app interface

Studium

React, Next.js, Figma

A quiet web app for studying and focused work.

GitHub

Also in the collection

  1. 01XSJ BilliardBilliard cue shop with a headless CMSAstro, Decap CMS
  2. 02BinusMaya sentimentSentiment analysis of user feedback on the BinusMaya appPython
  3. 03Superstore dashboardCohort analysis with LOD expressionsTableau
  4. 04TUMBASHealth info and consultations against stuntingFigma
  5. 05PerpustakaanLibrary database with a fully mapped ERDNext.js, MongoDB
  6. 06Social media appDesktop GUI on a local databaseJava, XAMPP
II

The underpainting

The part nobody looks at. L1 tech support at Dewaweb and IT architect work on Dewacloud taught me what happens after you press deploy. Here's one request, from the domain down.

  1. 01Domain and nameserversparamita.app NS dewaweb

    Where a domain gets its answers from. I kept paramita.app's nameservers on Dewaweb cPanel because the mail is simple there, and pointed only the web records out to the VPS.

  2. 02DNS recordsapi A vps · @ MX cpanel

    A, CNAME, MX, TXT, and how long a change really takes to reach everyone. One domain can send web, API and mail to three different places.

  3. 03SSL443 tls auto-renew

    Certificates on cPanel hosting and on my own servers, and working out why a browser says a site isn't secure.

  4. 04Reverse proxycaddy → web:3000 api:4000

    Caddy sits in front, handles HTTPS and decides what goes where.

    Field noteEvery visitor on terminal.ai.id showed up as 172.17.0.1. Docker's userland proxy owned ports 80 and 443 and hid the real address. Moving Caddy to host networking brought it back.

  5. 05Containers and environmentsdocker compose up -d --build

    On Dewacloud I build environments around what each client needs. One example: a 3,000-outlet F&B chain that needed an ERP system, where I led the migration. My own terminal.ai.id is three containers on one node, run with Docker Compose.

    Field noteParamita has staging and production, plus one server left frozen. It holds the database my thesis was evaluated on, so a bad migration can't reach it.

  6. 06Load balancinglb → node1 node2

    I know how it works on Dewacloud, spreading traffic across nodes. I haven't needed one for real traffic yet, nothing I run is that big.

  7. 07Releasesreleases/20261015 ← current

    Every Paramita deploy is its own folder behind a symlink. Database dump before any migration, then 23 smoke tests. If they fail it switches back on its own.

    Field noteIt's been needed. On staging, a binary uploaded from Git Bash lost its execute bit, systemd refused it with 203/EXEC, and the switch back caught it.

III

From daydream to deployed

  1. Sketch

    Talk first. What it's for, who it's for, what can be cut.

  2. Underpainting

    Flows and structure. Where the data lives and where it'll be hosted.

  3. Colour

    Figma, then real code, with AI agents in the loop and me checking their work.

  4. Varnish

    Domain, SSL, deploy, test on a real phone, keep watching.

IV

About the daydreamer

Jason Sebastian in a maroon blazer, one finger raised, thinking

I started out designing screens for clients. Then I wanted to build them, then I wanted to know where they actually live. So now I do all three, and a design of mine rarely stops at Figma.

I'm finishing Business Analytics at BINUS, working at Dewaweb, and building Paramita in whatever hours are left. I also help run events at my vihara. When I'm not at a screen I'm swimming laps or planning my next shot at a pool table.

AI coding agents are part of how I work now. They speed up the building. The design and architecture stay mine, and I check what ships.

Certificate, February 2026IBM Full Stack Software Developer15 courses, from React and Node.js to Django, Docker, Kubernetes and microservices, ending in a capstone project.Verify on Coursera

Provenance

  1. Feb 2026 to nowDewaweb L1 Tech Support for hosting, domains, DNS and SSL. IT Architect on Dewacloud, building client environments. Ninja of the Month in May and June 2026.
  2. 2024 to nowFreelance UI/UX design and front-end for clients, 10+ projects.
  3. Until Feb 2027BINUS University Business Analytics, GPA 3.83.
  4. 2020 to nowVihara Delapan Jalan Mulia Head of Events, youth staff.

Materials

  1. DesignFigma, UX research, design systems, prototyping
  2. Front endAstro, React, Next.js, Flutter, TypeScript
  3. Back endGo, Node, PostgreSQL, Redis, Java
  4. InfrastructureLinux, Docker, Caddy, systemd, DNS, cPanel, Dewacloud
  5. WorkflowGit, GitHub, Playwright, AI coding agents
  6. DataPython, SQL, Tableau
  7. LanguagesIndonesian, English, some Mandarin
Certificates (10)
  • Data Analyst Associate DataCamp, 2025
  • AI Fundamentals Dicoding, 2024
  • Back-End Development with JavaScript Dicoding, 2024
  • Cloud & Generative AI with AWS Dicoding, 2024
  • JavaScript Fundamentals Dicoding, 2024
  • Dart Fundamentals Dicoding, 2023
  • SQL Fundamentals Dicoding, 2023
  • Data Science Fundamental Dicoding, 2023
  • Project Management Dicoding, 2023
  • Web Development Fundamental Dicoding, 2023