Loris Léonard

Artradeis a French platform dedicated to Real-World Assets (RWA).

It allows users to purchase luxury goods viaSolanatransparently and deterministically. The platform initially offered discounted items through raffles and now includes auctions and booster packs.

Designed and maintained the backend inDenowithHono(asynchronous REST routes, database, business logic), ensuring thetransparency andconsistentexecutionof features such as raffle winners, auctions, booster packs, and buybacks.

Implementedscheduled cron jobsfor the notification system, balance verification, raffle closures, and activation of automated actions on user funds and RWA services.

Managed backend interactions withSolanato send funds to users, ensuring the correct amount, preventing duplication, and guaranteeing reliable execution.

Addedreal-timefeatures with **Socket.IO**, allowing users to instantly see updates and auction activity.

Improved reliability through centralized error management, logging viaSentry**, layer separation, and ensuring endpoints adhere to **backend best practiceswith proper validation, strict typing, and consistent database state.

https://artrade.app/

Japanese Leader,I providedDeFi datato themost used crypto tax solution in Japanand developed a new portfolio tool to strengthen Pafin's DeFi offering. A key part of the work involveddecoding smart contractsfrom dapps on multiple blockchains to determine where assets were stored (liquidity, staking, rewards) and performing advanced transaction decoding for tax purposes. This allowed us to correctly calculate taxes and give users a clear view of their holdings.

Designed scalable backend services inPythonwithPostgreSQL**, **Twirp**RPC** (Protobuf), andblockchain JSON-RPCintegrations, using asynchronous executions with retries, as well as caching for real-time data.

Automated the decoding of **millions of transactions on Ethereum**, Polygon, Optimism, and Arbitrum, extracting actionable fields for analysis and tax services.

IntegratedWeb3 librariesto analyze how protocols store assets in smart contracts tostudy DeFi positions(liquidity, staking, swaps) on Uniswap, OpenSea, Aave, Curve, and Velodrome.

Developed the frontend fromFigmadesigns withNext.jsand **TypeScript**, integrating APIs and optimizing loading time and performance.

Conducteddaily code reviewsand refactoring to improve code quality, consistency, and maintainability across backend and frontend projects.

🔍Cryptact - The cryptocurrency tax reporting platform:https://www.cryptact.com/en

🔍Defitact - The Web3 portfolio to track your DeFi positions:

https://www.defitact.com/en

Greisch Engineering is amajor engineering and architecture firm in Europe**. I designed and developed a **messaging and archiving systemfor architects and engineers, managinghundreds of thousands of emails**over 10 years**. The system supported real-time archiving, precise project-based tracking, and efficient handling of large attachments, helping architects and engineers work more effectively.

Led the system analysis**, requirements gathering, and **architectural designto modernize a legacy platform used by engineering and architecture teams.

Developed scalable web APIs in.NETandNode.jswith **PostgreSQL**, Microsoft plugins, caching, load-balancing, and asynchronous execution with retries, to process large email archives, metadata, and 3D files.

Delivered anautomated email archiving solutioncovering **over 10 years of data**, with project-based storage and seamless file retrieval.

ImplementedCI/CD pipelines**, **reducing deployment friction,decreasing downtime, and increasing delivery speed.

Optimized the processing of large files and attachments, whichaccelerated internal operationsand engineer data access.