Fintech

Cardless Installment Payment System

A complete consumer installment platform — from consumer applications and merchant management to payment gateway integration, covering the entire loan lifecycle.

Project Overview

3
Subsystems
Consumer App + Merchant Portal + CMS
74
API Endpoints
13 public + 61 admin
32+
Feature Pages
Full multi-platform coverage
12+
External Integrations
Firebase, Twilio, LINE, etc.

Challenges

The complexity of a financial system lies not in any single feature, but in the fact that every step must be flawless

01

Full Loan Lifecycle Management

From application, review, disbursement, repayment to overdue handling — each stage has strict business rules and state transitions. The system must precisely handle installment calculations, interest rate simulations, and late penalties without a single cent of error.

02

Multi-role Complex Permissions

Consumers, merchants, sales agents, reviewers, system admins — five roles each with different operation permissions and data visibility. Merchants also have sub-levels for sales agents and product management.

03

Financial-grade Compliance

Legally binding e-signatures, identity verification (KYC) must be in place, and Taiwan-specific ID numbers, mobile, and landline formats all require validation. All operations must leave audit trails.

04

Multi-platform Simultaneous Delivery

Consumers apply for installments on mobile (iOS/Android/Web), merchants manage cases via the portal, marketing content updated through CMS — three systems must be developed simultaneously with real-time data sync.

3 Subsystems, Full Coverage

Consumer, merchant, content management — each with a clear role, data synced in real time

Consumer App

Flutter
198Source Files
38Data Models
32+Feature Pages

Covers installment applications (multi-step forms), e-signatures, repayment tracking, credit limit management, and push notifications. Supports iOS, Android, and Web.

Merchant Portal

Laravel
18Controllers
74API Endpoints

Covers application review workflows, merchant and sales agent management, product catalog, case processing (payment/refund/partial payment), and report exports.

Content Management

Strapi

Marketing materials, product catalog, installment term settings, and homepage carousel management.

Feature Highlights

Multi-step Installment Application

Consumers fill in personal info, contact details, loan info, identity verification, and contract signing — each step with real-time validation to ensure data accuracy.

Case Management Workflow

The merchant portal supports application filtering, status tracking, and batch exports. Case processing covers standard payment, partial payment, multiple payments, and refunds — all financial operations fully logged.

Real-time Notification Integration

Firebase push + LINE OA messages + Email notifications + Twilio SMS/OTP verification — ensuring every critical touchpoint reaches the consumer in real time.

Reports & Exports

One-click export of Excel reports, PDF contracts, and Word documents. Supports filtering by date, status, merchant, and other dimensions.

Technical Architecture

Consumer App
iOS / Android / Web
Backend API
Laravel · 74 APIs
External Services
Firebase · Twilio · LINE · PDF
CMS
Strapi · Products/Marketing
REST API Communication

Key Metrics

Subsystems
3Consumer App + Merchant Portal + CMS
App Source Files
198
API Endpoints
7413 public + 61 admin
Feature Pages
32+
Data Models
38+
Controllers
18
Taiwan-specific Validations
5
External Integrations
12+Firebase, Twilio, LINE, PDF signing, Excel, etc.
Deployment Platforms
4iOS, Android, Web, Admin Portal
Deployment Environments
3Dev/Staging/Production, GKE containerized

Results

Fully Online Loan Process

From application to contract signing to repayment, consumers complete everything on their phone

Merchant Self-management

Merchants can independently manage sales agents, products, and review cases without relying on the platform

Financial-grade Precision

Zero errors in installment calculations, penalty calculations, and accounting

Compliance & Audit

E-signatures, KYC verification, and complete operation audit trails

Tech Stack

FlutterLaravelStrapiFirebaseTwilioLINE OAGKEDockerREST APIPDF E-signatureExcel ExportOTP Verification

Related Cases

Healthcare

Patient Information Management System

Multi-system integration platform for a major regional hospital

Health Tech

Health Management & Online Course Platform

Complete digital transformation solution for clinics

Have a fintech or trading platform need?

No spec sheet needed, no waiting for quotes. Describe your needs and Mia will analyze them for you instantly.

I want to build an installment payment systemI need payment gateway integrationHow to integrate e-signatures?How to apply for a free POC?