01 / 052025DESIGNED AND DEVELOPED END TO END
Enterprise management system
Custom ERP with CRM, operations, finance and electronic invoicing integrated directly with ARCA.
A single platform connecting CRM, quotations, purchasing, sales, electronic invoicing, finance, inventory and projects on one database and a granular permission model.
- YEAR
- 2025
- ROLE
- End-to-end development
- STATUS
- Documented case
Context
Operations were spread across spreadsheets, loose documents and manual routines. The goal was an internal platform where each piece of data is entered once and travels through the commercial, operational and financial process.
What I built
I developed the data model, backend, web interface, PDF generation, external integrations and a PWA for field work. I also designed users, roles and action-level permissions.
How it works
The flow starts in the CRM with a client, opportunity and quotation. Approval generates orders, inventory movements, project tracking and the relevant administrative steps. Dashboards read the same database with no parallel entry.
Integrated electronic invoicing
The system communicates directly with ARCA, obtains and records the CAE and keeps the voucher linked to its originating commercial record. Invoices and notes are issued without re-entering data in another platform, with PDF output and full traceability.
Features and modules
- CRM and client management
- Quotations and sales pipeline
- Purchasing and sales
- ARCA electronic invoicing
- Credit and debit notes
- Cash and financial flow
- Bank reconciliation
- Inventory and stock
- Project management
- Service orders
- Offers and PDF documents
- Commissions and receipts
- Roles and permissions
- Technician PWA
- Reports and integrations
Technical architecture
PHP application on MySQL/MariaDB with PDO and prepared statements. JavaScript and Tailwind CSS in the interface; Chart.js and Frappe Gantt for visualisation; Dompdf for documents. The PWA reuses the same data layer.
Technical decisions
One relational database prevents manual reconciliation between invoicing, stock and projects. Permissions resolve by role and action, and documents are generated from the actual system record.
Results
More than fifteen people use it every day. The system replaced a third-party management platform with a monthly cost, and it also covers processes that tool never handled: electronic invoicing inside the same flow, service orders, commissions and field work. Information that used to sit across spreadsheets and loose documents now lives in a single database: one place to search and one place to correct.
Privacy
Screenshots use fictional data. Real names, users, phone numbers, clients, salespeople, amounts and internal identifiers were removed.
Frequently asked questions
What people usually ask.
What is this system?
An ERP and CRM built from scratch connecting clients, quotations, purchasing, sales, electronic invoicing, finance, inventory and projects on a single database with role and action-level permissions.
How does the electronic invoicing work?
The system communicates directly with ARCA, obtains and records the CAE and keeps the voucher linked to its originating commercial record. Invoices and credit and debit notes are issued without re-entering data in another platform.
What technologies is it built with?
PHP on MySQL/MariaDB with PDO and prepared statements. JavaScript and Tailwind CSS in the interface, Chart.js and Frappe Gantt for visualisation, Dompdf for documents and a PWA reusing the same data layer.
Which parts did Thiago Lamonico develop?
The entire project: data model, backend, web interface, PDF generation, external integrations, the field PWA and the users, roles and permissions scheme.
Technology stack
Gallery
The complete interface.
Private screenshots use fictional information.
