Janaka Jati Lasmana / Sr. Frontend Engineer

I’m Jati.
I build mobile apps.

I’m a Sr. Frontend Engineer at Jago Coffee. I work with React Native, from mobile architecture and UI to builds and store releases.

See the apps

Download full CV PDF · Google Drive

10+years building

200K+users reached

4.9★app rating

Selected work

Explore my projects, tools, and contact details.

Go ahead, try the tabs. This phone works.

The teams I’ve worked with

Different products.
More to learn.

These days I’m at Jago Coffee. Alongside my team roles, I also work with clients on freelance and project-based builds.

I like being close to the whole app.

I’ve worked on shopping, healthcare, insurance, and logistics apps. Sometimes the job is a new screen. Sometimes it’s untangling the architecture or making the next release less painful. I enjoy both.

Freelance / Project-based

Independent

Mobile & Web Developer

Oct 2018 – Present

Available for freelance development and project-based collaborations.

Discuss a project

Jago Coffee

Senior Frontend Engineer

Feb 2025 – Present

Part-time

Corom

Fullstack React Native Engineer

Feb 2025 – Jul 2026

Cosmart

Senior Mobile Engineer

Jan 2023 – Jan 2025

Choir Express

Senior Mobile Engineer

Feb 2020 – Jan 2023

Generali Indonesia

React Native Developer

Mar 2019 – Feb 2020

Aegislabs

Junior Software Engineer

Jun 2016 – Feb 2019

How I work

A good app goes deeper than the screen.

I care about how it feels to use—and how it feels to work on six months later.

iOS & Android

Swipe the cards, or tap to turn the stack.

Mobile architecture & UI

I build with React Native, Expo, and TypeScript, defining component boundaries, managing state, and refining touch interactions.

Services & integrations

I connect APIs, Firebase, notifications, and purchases, including the loading and error states visitors encounter when a request is slow or fails.

Performance & delivery

I investigate slow interactions and rendering, then test the fixes. I also handle store releases, OTA updates, and maintenance after launch.

Automation

I use GitHub Actions and Fastlane to automate repeated build and release steps.

The part after “it works on my machine”

It still has
to ship.

I connect services, check builds, and handle releases alongside the screen work.

From the first screen to someone’s phoneFollow along ↓

01 / Interface
Get the feel right.
Build the screens and test touch interactions.
02 / Integration
Make it work together.
Connect the data and services, including the loading and error states.
03 / Automation
Stop repeating yourself.
Put repeatable build and release steps into a pipeline.
04 / Delivery
Get it into people’s hands.
Release to the stores and maintain the app after launch.

A simplified view of the work. The exact steps depend on the app.

Selected projects

Here’s what I’ve worked on.

A few apps I’ve helped build, and what I did on each one. These are the teams’ products; the notes below describe my part.

Scroll to open the folder. Pick an app to look closer.Pick an app to see what I worked on.

01 / Coffee delivery