Open for remote work

Ariyanto

Backend & Integration Engineer for payment and telecom gateway systems

I build and keep alive the systems that move a transaction from a phone to a provider and back, reliably and in real time. For 19+ years I have run MD Engine, a platform for electronic top-up (pulsa) servers that ties together GSM, XMPP, HTTP APIs, and payment rails. Now opening up capacity for remote contract work.

WhatsApp Email me GitHub md-engine.com Download CV

Sukoharjo, Indonesia UTC+07:00

Portrait of Ariyanto
  • SMS received
  • Routed to provider
  • Settled, balance updated
19+Years building and maintaining production systems
8Languages across backend, desktop, and mobile
4Integration protocols: GSM, XMPP, HTTP, WebSocket
885Dongle licenses sold to resellers across Indonesia

Case study: MD Engine

A full-featured top-up server, sold as a licensed product to resellers across Indonesia.

The problem

Electronic top-up (pulsa) resellers need one dependable server that takes orders from many channels, picks the right supplier, and never loses or double-processes a transaction, without being pushed into a stripped-down mini or limited edition.

The solution

I built MD Engine as a single full-featured server. It accepts requests over SMS, XMPP/Jabber, Telegram, WhatsApp, web, and API, routes each one to a supplier by priority, switches automatically when a supplier goes offline, and guards against duplicate transactions. Setup guides, FAQ, and release notes are published openly at md-engine.com.

The outcome

MD Engine is licensed per dongle and has sold 885 licenses to resellers across Indonesia. It is still maintained, with a published update as recent as January 2025.

885Dongle licenses sold across Indonesia
6+Request channels: SMS, XMPP, Telegram, WhatsApp, web, API
Jan 2025Most recent published update
  • Built across eight languages: C++ libraries and DLLs, a C# Telegram center module, a PHP transaction API, and more
  • Automatic supplier failover when an XMPP/Jabber supplier goes offline
  • Duplicate-transaction protection when two centers receive the same destination at the same moment
  • PPOB modules including PLN postpaid, custom H2H routing, and regex-configurable print formats
  • Reseller tooling: points system, product clusters per center, scheduled product offline hours, MSISDN blacklist
  • Voucher entry through the phone camera (scanner/OCR) to avoid typing mistakes
  • Automatic price updates by parsing supplier replies
  • XMPP / Jabber
  • Telegram
  • WhatsApp
  • SMS gateway
  • Web service
  • USSD
Read the documentation

How a transaction travels

A typical path through the MD Engine gateway, from an incoming message to a confirmed top-up.

GSM / SMS / WA input MD Engine gateway routing + auth REST API layer settlement Provider / bank confirmed
  1. GSM / SMS / WAinput
  2. MD Engine gatewayrouting + auth
  3. REST API layersettlement
  4. Provider / bankconfirmed

Illustrative simulation of a top-up request. Not live data.


          
        

      

    

  

  

  
  
  
  

    

      

        
Watch me code

        
A look at my day-to-day work: writing and debugging code.

      

      

        
          
          
        
      

      
Watch on YouTube

    

  

  

  
  

    

      
Expertise

      

        
        

          
Languages

          
  • C++
  • C#
  • VB6
  • VB.NET
  • PHP
  • Java
  • Kotlin
  • JavaScript

        

        
        

          
Platforms & tools

          
  • Node.js
  • Android Studio
  • MySQL
  • Firebase
  • Git
  • Visual Studio
  • REST API

        

        
        

          
Integration & protocols

          
  • GSM
  • XMPP
  • HTTP API
  • WebSocket
  • SMS Gateway
  • WhatsApp API

        

        
      

    

  

  

  
  
  

    

      
Experience

      

        
        

          
2007 to present

          

            
Founder & Developer

            
MD Engine

            
  • Designed and built server software for electronic phone-credit (pulsa) top-ups, running continuously since 2007.
  • Integrated multiple transaction protocols end to end: GSM, XMPP, and HTTP APIs.
  • Provided direct technical support to hundreds of users on live production systems.
  • Kept the platform operating and supported through shifting market and economic conditions.

            md-engine.com
          

        

        
      

    

  

  

  
  
  

    

      
Selected work

      

        
        

          C++, C#, PHP, VB6, VB.NET, Java, Kotlin, JavaScript
          
api-mdengine

          
Core software of MD Engine's top-up server, built across all eight of my languages: C++ libraries and DLLs, a C# Telegram center module, a PHP transaction API, and more.

        

        
        

          Android, Kotlin
          
WhatsApp Gateway for Android

          
Gateway app for sending top-up confirmations and transaction alerts through the WhatsApp API.

        

        
        

          Node.js, WebSocket
          
Real-Time Transaction Monitor

          
Live monitoring system for tracking transaction status across the gateway as it happens.

        

        
        

          Android, REST API
          
API Debugging Toolset

          
Tools for inspecting and debugging provider REST APIs (Digipos, Rita, Sidompul) during integration work.

        

        
        

          Kotlin, MVVM
          
ABMediaAndroid

          
Online store Android app built on a clean MVVM architecture.

        

        
        

          Kotlin, template
          
MVVM Starter Template

          
Reusable MVVM project template for Android Studio, used to bootstrap new apps faster.

        

        
      

    

  

  

  
  
  

    

      

        
Open for remote work

        
Available for freelance or contract roles in backend development, API and payment gateway integration, and Android app maintenance. Comfortable working async across time zones.

        
        
        
        
        
        
        

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        Chat on WhatsApp
        
        
        arie.emdee@gmail.com
        
        github.com/arieemdee
        
        md-engine.com
        
        
        
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