Vue.jsFirebaseAstroDockerSAPNode.jsTypeScriptTailwindCSSKotlinDartJetpackComposeFlutter
Alex Kristian

Hi there, I'm Alex Kristian
SAP ABAP Developer · S/4HANA RISE Public Cloud · Full-Stack SAP Integration

I build on S/4HANA RISE Public Cloud, mostly in FI, PS, FM, and MM. Most of my work is reports on CDS and AMDP, and the upload and posting programs finance runs on. I came into SAP from web and mobile development, so the integration side is familiar ground rather than a separate skill.

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Services

Where I can help, from the ABAP side through to getting it deployed.

Custom SAP ABAP Development

Z-programs, BAPIs and function modules, BAdIs and User Exits, CDS and AMDP models, OData services, and real-time push channels. On S/4HANA and on ECC.

  • OO ABAP
  • BAPI
  • BAdI
  • CDS / AMDP
  • OData
  • ABAP Unit

Node.js Backend

REST APIs with a layered structure, Redis where caching earns its place, CI/CD, and payment gateway integration with Xendit.

  • Express
  • TypeScript
  • Redis
  • Docker

Mobile Development

Android apps in Kotlin, and Flutter when the app has to run on both. Architecture that survives the second year, and interfaces people can actually use.

  • Kotlin
  • Jetpack Compose
  • Flutter
  • Firebase

Data & Reporting

Reports people trust enough to act on: CDS and AMDP so the work happens in HANA, ALV with drill-down, and a baseline check so a rule change never moves the numbers quietly.

  • CDS Views
  • AMDP
  • ALV
  • SQL

DevOps & CI/CD

Builds across several environments, monitoring, and releases that can be rolled back.

  • GitHub Actions
  • Docker
  • PM2/Compose

System Integration

Booking synchronization, webhooks, HMAC authentication, and digital signatures.

  • Webhook
  • Signature
  • Security

Experiences

Where I have worked, starting with two internships in 2023.

  1. Sep 2022 – Sep 2024

    Course Instructor & Manager · Lembaga Pengembangan Komputerisasi, Universitas Gunadarma

    Taught networking, SQL Server, MySQL, Oracle, C#, and Java. I rewrote the beginner networking material and coordinated the assistants who graded students.

    • Networking
    • SQL Server
    • MySQL
    • Oracle
    • C#
    • Java
  2. Aug 2023 – Oct 2023

    Android Developer Intern · Wowrack Indonesia

    Built the Android app for the company's cloud service: fingerprint and face login, support tickets, and push notifications on top of the cloud team's REST API.

    • Kotlin
    • Android
    • Biometric Auth
    • REST API
    • Push Notification
  3. Sep 2023 – Dec 2023

    Mobile Developer Intern · BMKG (Meteorology, Climatology, and Geophysics Agency)

    Worked on Get Safe, a Flutter app for disaster warnings. I built the APIs the mobile side needed, designed the flows for the new screens, and made the overlay that interrupts whatever app is open when BMKG issues an earthquake, tsunami, or volcanic warning.

    • Flutter
    • Dart
    • Node.js
    • REST API
    • Firebase (FCM)
    • UI/UX
  4. Dec 2024 – Jan 2026

    Software Engineer · PT Harfan Tri Megah (Edugate Indonesia)

    Vue.js and Node.js applications wired to SAP over OData, plus SAPUI5 apps. I wrote the ABAP side as well, custom programs, User Exits, and BAdIs. Set up the Docker environments for DEV, QAS, and PRD behind an Nginx reverse proxy, and connected outside payment and booking platforms to SAP. The two I spent most of my time on were Padel Play and Bussim.

    • Vue.js
    • Node.js
    • TypeScript
    • SAP OData
    • SAPUI5
    • ABAP
    • User Exit
    • BAdI
    • ABAP Push Channel
    • Docker
    • Nginx
    • Xendit
  5. Jan 2026 – Present

    SAP ABAP Developer · PT Agung Sedayu Group (ASG)

    RICEFW work on S/4HANA RISE Public Cloud, mostly in FI, PS, FM, and MM. Reports built on CDS and AMDP, upload and posting programs for finance running on a shared upload engine, and the authorization behind them. I also keep the CPI and SAP Build Process Automation flows alive, including the time an expired SSL certificate quietly stopped document posting. Project details are limited under NDA.

    • OO ABAP
    • AMDP
    • SQLScript
    • CDS Views
    • Posting Interface
    • Parked Document
    • PFCG
    • S/4HANA Public Cloud
    • CPI
    • SAP Build Process Automation

Projects

SAP programs, backend services, and a few mobile apps.

Report Tracking Payment

The report the group uses to follow a contract from work order to invoice to payment. I rebuilt it on seven CDS views feeding one wide ALV, which cleared up the double counting that showed up whenever the same amount sat in more than one document type. Retention and multi-currency came with the rewrite. Before any rule change went live I checked it against figures the business had already signed off, in DEV, QAS, and against production data.

OO ABAPCDS ViewsALVS/4HANA Public CloudFIMulti-currencyNDA

PS Commitment Monitoring Report

Budget monitoring for Project System. AMDP and SQLScript CDS views feed an ALV Grid showing WBS budget and how commitments move from purchase requisition to purchase order. It also sorts out the double counting that came from the procurement data. I kept it modular, so a new rule or column does not mean opening up the core.

AMDPSQLScriptCDS ViewsALV GridPSFMNDA

AP Payroll Upload & Posting

Two programs that work as one flow. The first reads the payroll file, checks every row against master data, and parks the documents. The second is where someone approves, rejects, or posts them. A rejected row cannot be left without a reason, and what each user is allowed to touch is scoped per user. It cut the manual posting mistakes during the stabilization period after go-live.

OO ABAPFI-APPosting InterfaceParked DocumentAuthorizationALVNDA

FI Initial Balance Upload

Loads opening balances from a spreadsheet or a text file during FI conversion. Every row is checked against posting key, customer, and vendor master data before anything posts, then goes through currency conversion and tax calculation. The posting itself sits inside a commit and rollback, so a batch that fails does not leave half a migration behind. Each row keeps its own message, so a rejected line says why it was rejected.

ABAPBAPIFIData MigrationALVCurrency ConversionNDA

Excel Mass-Upload Framework

Every upload program was growing its own way of reading files, so I moved that into one shared engine. A single reader, mapping driven by DDIC, master data validation, duplicate detection, and an error log in ALV that takes you straight to the row that failed. Two modules run on it so far, payroll and FI conversion.

OO ABAPDDICALVReusable EngineData ValidationNDA

Cash Advance & Payment Planning

Cash advance and payment execution. Partial realization was added, and the internal order validation that each program used to carry on its own now lives in one class they share. Payment planning handles parked documents and works out the profit center for budget execution.

OO ABAPFMFIParked DocumentProfit CenterNDA

Padel Play (Public)

A booking platform for padel courts. There were two of us on it; I took the backend and everything touching SAP ECC, which meant OData services, ABAP enhancements, and the table design behind them. Payments run through Xendit and bookings stay in sync with AYO Indonesia. Live since 1 January 2026.

Node.jsTypeScriptVue.jsSAP ABAPSAP ODataXenditDockerVA01VK11PA20

Padel Play (GRO)

The app the front desk actually works in: checking people in, handing out and taking back equipment, keeping track of which racket is where, and confirming who the customer is. Same two-person team, same split, so the backend and the SAP side were mine. Everything booked here lands in SAP and stays in sync with AYO Indonesia. Live since 1 January 2026.

Node.jsTypeScriptExpress.jsSAP ABAPSAP ODataOTP VerificationVA03Goods Issue

Bussim

A training simulation backed by SAP. Participants run Procurement, Production, Sales, Human Capital, and Warehouse while an instructor drives the game from a separate console. SAP pushes data to the browser over WebSocket, so cost, capacity, and material movement change while people are still deciding what to do next.

DashboardBusiness SimulationProcurementProductionSalesHRWarehouseData VisualizationWebSocket (SAPC / ABAP Push Channel)

Cloud Service Android App

Android app for a cloud service provider. Fingerprint and face login, support tickets, and push notifications on top of the cloud team's REST API. Only the onboarding screens can be shown here.

KotlinAndroidBiometric AuthREST APIPush NotificationNDA

Get Safe

An alert app that does not wait for you to open it. When BMKG issues an earthquake, tsunami, or volcanic warning, it takes over whatever is on the screen and shows the alert full size. I built the APIs the app needed and the overlay that does the interrupting, along with the flows for the new screens. Made during my internship at BMKG.

FlutterDartAndroidSystem Alert WindowNode.jsFirebaseFCMNDA

Indekosku

A boarding house marketplace I built on my own to try things out. MVVM with Koin for injection, Room so it still works with no signal, Firebase for live availability, and recommendations based on where you are. There is an AR view for looking around a room as well.

KotlinAndroidSelf ProjectMVVMKoin (DI)RetrofitRoomFirebaseFCMAugmented Reality

Skills

What I reach for, roughly in the order I use it.

ABAP Core

  • OO ABAP
  • AMDP
  • SQLScript
  • CDS Views
  • BAPI
  • BAdI
  • Enhancement Framework
  • User Exit
  • ALV / SALV
  • BDC
  • SmartForms
  • Transport Management

SAP Modern Stack

  • S/4HANA RISE Public Cloud
  • OData V4
  • RAP
  • SAPUI5
  • ABAP Unit Testing
  • Authorization (PFCG + AUTHORITY-CHECK)
  • CPI
  • SAP Build Process Automation
  • ADT / Eclipse
  • ABAP Push Channel (SAPC)

Module Exposure

  • FI (GL, AP, Document Splitting)
  • PS (WBS, Commitment, Network Order)
  • FM (Budget Execution)
  • MM (Procurement)

Backend & Web

  • Node.js
  • Express
  • TypeScript
  • JavaScript
  • Vue.js
  • Astro
  • REST API
  • WebSocket
  • Redis

Mobile Development

  • Kotlin
  • Jetpack Compose
  • Flutter
  • Dart
  • Room
  • Retrofit
  • Koin (DI)

Integration & Services

  • Xendit
  • Firebase / FCM
  • Webhook
  • HMAC Signature

Tools & DevOps

  • Docker
  • docker-compose
  • Nginx
  • Git
  • GitHub Actions
  • SQL
  • Figma

Contact

Working on something SAP-shaped, or just want to ask about one of these projects? Write to me.

or email me directly at alexkristianmalau@gmail.com