Senior Fullstack Developer

Senior Fullstack

Job 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) Platform & Integration
• 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
• Create and maintain custom APIs for cross-system integration
• Maintain system performance, stability, and data quality across the platform
• Work closely with cross-functional teams to translate procurement business needs into technical solutions
• Write detailed documentation for custom features and technical specifications Required Skills & Experience Technical
• 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

Senior Full-Stack Developer (Python) — Procure-to-Pay · Page 2

• 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
• Understanding of enterprise system integration patterns
• Proficiency with version control systems and CI/CD practices
• Understanding of cloud infrastructure and containerization
• Knowledge of modern frontend frameworks (Svelte, Frappe/Vue.js for ERPNext)
• Knowledge of internationalization and localization implementation
• Excellent written and verbal communication skills Testing & Test Automation
• 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 (requisition → PO → goods receipt → invoice)
• Experience integrating unit and Playwright test suites into CI/CD pipelines with coverage reporting
• Ability to set testing standards for the team and review others' test code Procure-to-Pay
• Solid understanding of the end-to-end P2P process and its data flow across purchasing,

inventory, and accounts payable

• Hands-on experience building or implementing P2P modules (e.g., ERPNext Buying/Accounts, SAP MM/FI, or similar) Domain Knowledge (Preferred)
• Approval workflow design, delegation of authority, and segregation of duties
• Two- and three-way matching, tolerance rules, and invoice exception management
• Supplier master data management, catalogs, and punch-out
• Budget control and commitment accounting
• Accounts payable, GL posting, and payment runs
• Thai VAT, withholding tax, and e-Tax Invoice requirements
• Exposure to e-procurement, e-invoicing, or supplier portal platforms

Technical

• More than 6 years of experience in Python development
• Proficiency in Python with willingness to learn related web frameworks
• Basic understanding of relational databases and SQL
• Basic understanding of authentication and security concepts
• Experience with Git; familiarity with CI/CD practices is a plus
• Basic knowledge of HTML, CSS, and JavaScript; experience with any frontend framework is a plus
• Comfortable reading documentation and learning new frameworks independently

• • CS degree or equivalent practical experience (bootcamp, self-taught with portfolio)