Custom Android, iOS & website development
Jostar.id helps businesses build mobile apps and websites that actually get used — from idea and design to a product your customers rely on. The initial consultation is free.
One complete system, not apps standing alone
We design and build business systems end to end — the customer side, the operations side, and the AI in between — then keep caring for them after launch.
Business Operations Systems
Orders, schedules, inventory, field teams, and financial reports in one system — no more manual recaps or data scattered across chats.
Customer-Facing Apps
Android, iOS, and web apps where customers book, shop, and pay — wired straight into the system behind them.
AI That Does the Work
AI connected to your business data — answering customer questions, reading photos and documents, writing content. Not a bolted-on chatbot.
Startup MVPs & Products
From idea to a product ready for market testing, on a foundation that can grow into a SaaS — and the source code is entirely yours.
Built with Flutter, Next.js, Supabase & Firebase, Midtrans & Xendit payments, and Claude as the main AI model for our latest products.
Already built once — now tailored to you
Every solution below started as a real app running in its users' hands — so you are not paying us to learn from scratch.
Not seeing what you need? Most of our projects are custom anyway — tell us about it and we will help map it out.
Discuss your needsHow we run your project
Consultation & scoping
Tell us what you need via WhatsApp. We help define features, scope, timeline, and a cost estimate — free, no commitment.
Design & architecture
App flows, UI/UX, and technical architecture are laid out first so the end result hits the mark and scales.
Development
We build your Android & iOS app (Flutter) or website (Next.js) with regular progress updates.
Launch & maintenance
Production deployment, source code handover, and optional maintenance and further development.
Want to see our work first? Check out our project portfolio, or go ahead and contact the Jostar.id team for a free consultation.
A safe engagement from kickoff to handover
We know handing a project to a developer is a big decision. So we share the risk with you — you don't carry it alone.
30-day bugfix warranty
Any bug found within 30 days after handover is fixed for free — no extra charge.
Milestone-based payments
Pay per milestone agreed up front, not everything in advance. You always see progress before paying the next stage.
Source code 100% yours
All code and access (repository, hosting, database) are handed over in your name. No lock-in to us.
Regular progress reports
Routine progress updates via WhatsApp, previews included. You always know exactly where the project stands.
Frequently asked questions
How much does a mobile app or website cost?
It depends on feature complexity and project scope. The initial consultation is free — tell us what you need and we'll help define the scope and give you a fitting estimate.
How long does development take?
On average 2–8 weeks depending on scope. A simple MVP can be faster, while multi-role apps or marketplaces take longer. The timeline is agreed at the start of the project.
Can one app cover both Android and iOS?
Yes. We build with Flutter — one codebase for both Android and iOS, saving cost and time without sacrificing native-level quality.
What technologies do you use?
Mobile apps: Flutter & Dart. Websites / web apps: Next.js, React, and TypeScript. Backend: Supabase or Firebase with PostgreSQL, plus payment integrations like Midtrans and Xendit.
Do I get the source code, and can I maintain it myself?
Yes. The source code is fully yours once the project is done. We also offer optional maintenance and further feature development if needed.
How do payments work?
In stages per milestone, not everything up front. The down payment is agreed at the start, and the rest is paid as you see and review progress at each stage.
What if bugs show up after launch?
There's a 30-day bugfix warranty after handover — bugs found in that period are fixed for free. After that, subscription or per-fix maintenance options are available.
How do I get started?
Contact us via WhatsApp for a free consultation. We'll help define your needs, scope, timeline, and a cost estimate before any work begins.
Ready to start your project?
The initial consultation is free. Tell us what you need and we'll help find the solution that makes the most sense for your business.