Axel R.

Full-stack design and development of an NFT marketplace - From

smart contract specifications to GKE deployment, including

full backend integration.

Solidity Smart Contracts (ERC-721)

- RivalNFT Contract V1 & V2 deployed on Polygon

- Override of _update() for complete transfer security

(platform-only)

- Automatic royalty system with multi-beneficiary USDC distribution

- Configurable revenue sharing with percentages out of 10000 (basis points)

- Token burning for transactional compensation

- Dual ID System (tokenId ↔ mediaInternalId) for O(1) queries

- ReentrancyGuard protection against attacks

- Commercial use rights management for secondary market

Python Tools / Blockchain CLI

- Interactive CLI (Python/Web3.py) for smart contract administration

- Token listing via on-chain Transfer events analysis

- Minting, transfers, revenue share management via command line

- Polygonscan API integration for log analysis

- Multi-threaded property fetching for performance

Backend & Blockchain Integration (PHP/Symfony)

- Polygon blockchain integration: minting, USDC transfers (ERC-20), burning

- Multi-smart-contract architecture with versioning

- Automated financial reconciliation (Stripe ↔ Blockchain ↔ Database)

- Gas fee management with dynamic estimation (+20% buffer)

Payments & Fintech Expertise

- Complete Stripe integration: Payment Intents, manual capture, refunds

- Stripe Tax API + fallback rates for 40+ countries

- Transaction state machine: 7-state workflow with automatic compensation

- Distributed locking for transactional integrity

Lead a team of 3 QA Engineers

• Automated the whole testing process of the solution including performance,

migrations and product pipelines integration.

• Quality Assurance tooling and enhancement: maintain proper tests, frame-

works and tooling for the whole solution. We led custom testing campaigns

on behalf of customers during implementations phases.

• Development of the official BI connector: from feature specification with customers and developments schedule to Quality Assurance and delivery. Our implementation is close to the Microsoft Analysis Services based on the XMLA standard. Currently supports Excel and Tableau.

• Quality Assurance tooling and enhancement: worked with a team of 3 QA engineers to maintain proper testing frameworks and tooling for the whole solution. Led custom testing campaigns on behalf of customers during implementations phases.