Custom business software / ERP
Integrated Business Management System — Website, ERP and Financial Operations
A custom business management system that connects the customer-facing website with customer and product management, account ledgers, debt and collection tracking, VAT calculations, cash, cheque and promissory-note operations, and operational reporting on one data model.
- Developed by
- TankDev
- Project type
- Client work · custom business software
- System
- Web application + ERP management layer
- Field
- Business management · financial operations
- Core modules
- Customers · products · ledgers · collections · reporting
- Frontend
- Next.js · Tailwind CSS
- Backend
- FastAPI
- Database
- PostgreSQL
- Platform
- Web
- Status
- Working system
PUBLIC WEB × BUSINESS OPERATIONS
From web project to business system
This project was not limited to rebuilding a corporate website. A custom ERP layer for the company’s day-to-day operations was developed inside the same system.
Customer records, product definitions, financial transactions, collections, payment instruments, and reporting were brought together around one backend and central data model. The public web experience and internal operations were treated as one engineering system.
Verifiable system scope
These indicators describe the verifiable scope of the software delivered, not commercial outcomes or usage volume.
The Problem Beyond the Website
A company’s digital system is more than the pages its customers see. Customers, products, amounts, VAT, account-ledger transactions, debts, collections, payment instruments, and reports are connected operational data. In this project, the public website and internal operations were designed as one system around a shared backend and data model, not as two disconnected products.
Engineering constraints
The system had to preserve relational integrity across financial records, associate customers with the correct transactions, and represent cash, cheques, and promissory notes within one financial model. New product definitions could not disrupt existing workflows; reports had to derive consistently from operational data; and the public website and internal management interface had to serve different users within one architecture.
DOMAIN MODEL
One System, Connected Business Data
Keeping customers, products, and financial transactions in a relational model—rather than as isolated records—allows person-, date-, and transaction-based reports to be produced from the same operational data.
ERP MODULES
A Custom ERP Layer
Customer Management
Create and maintain customer records, with linked operational and financial activity kept in one place.
Product Definition
Business users can define a new product or service and associate it with the relevant customer workflow.
Customer Account Ledger
Track financial transactions and the current financial position for each customer.
Debt and Collections
Record debts, process collections, and reflect each financial transaction in the customer account.
VAT Calculation
Manage transaction amounts and VAT calculations within the system workflow.
Payment Instruments
Record cash, cheque, and promissory-note payment or collection types.
Cheque / Note Status
Manage operational status changes for cheques and promissory notes and connect them to the relevant financial transaction.
Operational Reporting
Produce person-, date-, and transaction-based reports from operational records.
SYSTEM ARCHITECTURE
The Customer-Facing Web and Internal Operations Share One Architecture
The Next.js web layer, business rules in FastAPI, and relational operational data in PostgreSQL operate within one system boundary.
FINANCIAL OPERATION FLOW
How a Transaction Moves Through the System
This flow explains the system’s business domains without publishing client-specific accounting rules or formulas.
- 01Customer
- 02Product / Service
- 03Amount
- 04VAT
- 05Ledger transaction
- 06Debt
- 07Collection
- 08Cash / Cheque / Promissory note
- 09Financial position
- 10Reporting
REPORTING
From Operational Data to Reporting
Data created in the system is not stored only as a record. The same central data supports customer or person, date, and transaction views. Operational records and reporting are handled as different views of one data model rather than disconnected processes.
- 01Customer / person
- 02Date
- 03Transaction
Delivered Scope
Traditional website scope
- Public pages
- Content
- Contact
- Customer-facing experience
Delivered system
- Public website
- Customer management
- Product definitions
- Account ledgers
- Debt and collections
- Cash / cheque / promissory note
- Financial operations
- Reporting
- Central database
Why This Is More Than a Website
A website is the digital surface customers see. In this project, the same software system also manages customer records, product definitions, account ledgers, collections, payment instruments, and reporting. Because the public web, operations, and financial data work around the same backend and data layer, the delivery is custom business software connected to day-to-day operations.
Engineering Approach
Next.js provides a fast, crawlable public web layer. FastAPI keeps business rules and data access for public and internal interfaces behind one API boundary. PostgreSQL preserves relationships across customers, products, and financial operations. Tailwind CSS supports a consistent responsive interface across workflows.
Performance in the Public Web Layer
Measured categories in Google PageSpeed Insights tests score at 95+. This describes PageSpeed measurement categories; it is not a Core Web Vitals claim, a ranking claim, or a commercial-performance metric. Detailed category scores are not published without the measurement capture.
Technical Search Infrastructure
The public web layer provides crawlable page content, semantic HTML, page-level metadata, self-referencing canonical URLs, sitemap entries, robots directives, structured data, and responsive design. Turkish and English versions are connected through reciprocal hreflang links.
Data and Publication Boundaries
This case study does not publish real customer records, financial amounts, account details, cheque or promissory-note numbers, or client-specific calculation rules. It makes no unverified claim about security certification, the authorization model, or audit logging.
Related capabilities
Are separate systems still running behind your website?
Customer, product, financial transaction, and operational data can be brought together in one software system built around your business.
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