Description
Experience Level: Expert
Job Type: Hourly (Ongoing/Part-time)
We are expanding the core capabilities of our rapidly growing e-commerce ecosystem and are looking for a highly skilled Backend Developer. This is an hourly contract focused on building out resilient financial infrastructure, localized transactional logic, and high-throughput core APIs.
The ideal candidate brings deep architectural expertise in handling sensitive transactional data, integrating complex third-party APIs, and designing modular, secure backend components. This role requires an engineer who can work autonomously, provide precise hourly tracking against clear milestones, and deliver production-ready, highly secure code.
Scope of Work
Multi-Gateway Payment Orchestration: Design and implement a fault-tolerant payment routing system integrating multiple gateways (e.g., Stripe, PayPal, Adyen). The architecture must handle automatic failovers, split-payments, and strict ledger logging for financial auditing.
Dynamic Localization & Tax Engine: Build a reliable server-side module for real-time currency conversion and seamless integration with automated tax calculation APIs (such as TaxJar or Avalara) to handle multi-regional compliance.
Granular RBAC & Authentication: Deploy a highly secure OAuth2/OIDC authentication layer paired with robust Role-Based Access Control (RBAC) to safely manage access across administrative staff, vendors, and customers.
API Modernization & Refactoring: Optimize and refactor existing monolithic endpoints into highly performant, well-documented RESTful or GraphQL APIs, ensuring minimal latency and clean separation of concerns.
Tech Stack & Requirements
Strong proficiency in Node.js (NestJS/Express) or PHP (Laravel).
Proven track record of implementing secure payment integrations and handling webhooks idempotently.
Advanced knowledge of relational databases (PostgreSQL/MySQL) alongside data isolation and encryption best practices.
Experience with distributed systems, microservices architecture, and utilizing Redis for session management and distributed locking.
Ability to provide clear technical documentation and comprehensive integration test coverage.
Project Budget & Timeline
Payment Type: Hourly
Hourly Rate: $45 – $65 / hour (Dependent on depth of expertise)
Project Scale: Estimated 40–50 hours total allocation
Duration: 3–4 weeks with potential for ongoing architecture maintenance