Senior Fullstack Dev

About the role

Senior Full-Stack Developer (Python) — Procure-to-Pay. Design and develop end-to-end P2P workflows including purchase requisition, approval, sourcing/RFQ, purchase order, goods receipt, invoice, and payment. Extend open-source ERP systems (particularly ERPNext) to support P2P requirements and create secure integrations with enterprise systems for purchasing, invoice, and payment data synchronization.

Key responsibilities

• Design and develop end-to-end P2P workflows — purchase requisition, approval, sourcing/RFQ, purchase order, goods receipt, invoice, and payment
• Implement configurable approval matrices by amount, cost center, category, and delegation of authority
• Build two- and three-way matching (PO, goods receipt, invoice) with tolerance rules and exception handling
• Develop supplier management features — onboarding, master data, catalogs, and a supplier portal
• Implement budget control, including budget checking and commitment tracking against requisitions and POs
• Build integration of PO, invoice, and payment data with accounts payable, general ledger, and ERP systems
• Support Thai tax and compliance requirements — VAT, withholding tax, and e-Tax Invoice
• Implement audit trails and P2P operational reporting (PO cycle time, invoice exceptions, budget vs. actual)
• Extend open-source ERP systems (particularly ERPNext) to support P2P requirements
• Create secure integrations with enterprise systems (like SAP) for purchasing, invoice, and payment data synchronization

About you

• More than 6 years of experience in Python development
• Strong proficiency in Python and related web frameworks
• Experience with open-source ERP systems, particularly ERPNext, including module customization
• Proven experience building enterprise-scale applications
• Deep understanding of database design and optimization — especially for large-volume transactional data
• Experience with modular software architecture, micro-services, and event-driven architectures
• Knowledge of authentication, authorization, and security best practices
• Experience with workflow engine implementation and real-time data synchronization
• Strong experience writing unit and integration tests in Python (pytest), including fixtures, mocking, and test data setup
• Hands-on experience building automated UI / end-to-end tests with Playwright, covering critical P2P flows