E Muhammad Rayhan Elrayn
ID EN

Full-stack Developer

Muhammad Rayhan — Elrayn

I build web systems from database and backend through to frontend, with no split between FE/BE roles. 9 years of coding, 4 of them professional, spanning payment gateway and OTA integrations, ERP, and financial reporting.

About

I handle systems end to end

I'm Rayhan. I've been coding for about 9 years, 4 of them professionally on contract. At work there's no split between frontend and backend teams: every developer handles both, including the JavaScript layered on top of whatever admin template we're using. Beyond web projects, I also maintain legacy code and build integrations between systems, from payment gateways and third-party APIs to hybrid mobile apps.

9 Years coding
4 Years professional

Skills

Tools I use day to day

Backend

PHP (Laravel, CodeIgniter 3), Node.js, Java (legacy maintenance)

Frontend

Vanilla JavaScript, jQuery, admin template customization

Mobile

Ionic + Cordova (hybrid apps)

Database

MySQL

Integrations

REST APIs, payment gateway (Espay), OTA APIs (Traveloka, RedBus, EasyBook), third-party ERP APIs (Jubelio, Moka, Runchise)

Other

Financial/GL reporting (balance sheet, income statement), data export for Coretax

Projects

Personal project

Projects & Case Studies

Most of this was built for clients or an employer, so it's written as a summary of the role and tech involved, without sharing anyone else's code or data.

Personal

Grevel

A Flutter app for teachers to manage student scores — bulk Excel import, OCR mark-sheet scanning, and per-class PDF label generation. Still in active development.

Flutter Dart SQLite Google ML Kit OCR
Personal

table-export

An open-source PHP library for exporting tabular data to Excel or PDF through one consistent API, without rewriting similar export code across report controllers. Automatic column width, bold headers, and borders.

PHP PhpSpreadsheet dompdf
Personal

approval-flow

A lightweight PHP state machine library for multi-step approval workflows with role-based access control — declare the workflow graph once, then validate whether a transition is allowed, instead of scattering if-else checks across controllers.

PHP Composer PHPUnit
Personal

jquery-lookup-modal

An open-source (MIT) jQuery plugin for building searchable, modal-based record pickers without hand-building a custom "search and select" UI every time — integrates with DataTables, keyboard-driven (F4/Enter), auto-fills the form on selection.

jQuery Bootstrap DataTables
Freelance

Dental Clinic Management System

A management system for dental clinics: patient registration, a queue system (take a number, call next), per-visit examination records, a service/medicine catalog, and a printable patient card.

PHP Laravel MySQL
Freelance

Decision Support System (DSS)

Several decision-support apps built on decision-making algorithms, one of them for adolescent nutrition, to help automate assessment and recommendations.

PHP MySQL Metode SPK
Freelance

Hotel Management & Booking System

A hotel management app covering the booking flow, room data, and operational reporting.

PHP MySQL
Freelance

AI-Based Academic Evaluation Dashboard

An AI-based dashboard evaluating student academic performance for educational institutions, built as part of a client's dissertation project, with a supporting LMS module.

PHP (CodeIgniter) MySQL AI integration
Freelance

Digital Waste Bank System

A transaction-tracking platform for a community waste-bank program, where residents deposit waste and receive digital incentives.

PHP (CodeIgniter 4) MySQL
Freelance

IoT & AI-Based Evaluation System

An evaluation system for electrical engineering/CS students' practical work, using IoT and AI to assess embedded-system work in real time, built as a client's dissertation project.

PHP IoT AI integration
In-house

Bus Ticketing Platform — PT Kramatdjati

A ticket-sales system for agents and the public, including API integrations with third-party OTAs (Traveloka, RedBus, EasyBook) and an in-progress payment gateway (Espay) build.

PHP MySQL REST API Payment Gateway
In-house

Bakery Factory ERP

An ERP system for bakery-factory operations, integrated with third-party platforms (Jubelio, Moka, Runchise) via API to sync sales and stock across channels.

PHP REST API Integrasi multi-channel
In-house

Accounting & Reporting System

An accounting module with General Ledger reports (balance sheet, income statement) and an invoice export to Excel for Coretax import.

PHP MySQL Reporting
In-house

Library System Maintenance

Revisions to a legacy Java program that acts as middleware between self-checkout/drop-book machines and the library database, translating hardware commands and sending responses back.

Java Middleware
In-house

Restaurant POS App

Development and revisions to a restaurant POS app: hybrid mobile frontend with Ionic + Cordova, Node.js backend.

Ionic Cordova Node.js

Contact

Want to talk about a project?