- Parallel working as backend and blockchain developer; integrate De-Fi blockchain and research hot trending such as NFT (OpenSea), BSC (PancakeSwap, Beefy) - Optimize Multi-Wallet service which tracking and nonce management, also re-broadcasting if the transaction is discarded from the public node - Implement business logic for flex saving, launchpad vesting schedule, lottery lucky draw based on dividing tickets, wheel spin based on prize weight - Contribute to developing native contract based on LGE Whitelisted and research the upcoming contract such ERC721 for NFT (ongoing) - Wallet service which tracking and nonce management, also re-broadcasting if the transaction is discarded from the public node - Implement business logic for flex saving, launchpad vesting schedule, lottery lucky draw based on dividing tickets, and wheel spin based on prize weight - Build custom perpetual trading on 2 DEX Arbitrum One/ZK Polygon based on GMX and Vela using solidity and upgradable proxy pattern by OpenZeppelin, also build backend components - Researching AI trends such as Stability Diffusion and apply to the backend - Stack: Microservices and partial with Java 11/17/21 and Spring Boot, Jupiter Junit 5, Kafka, MySQL, Docker, NodeJS, VueJS, and Solidity

+ Develop core blockchain library which let other services can integrate to generate address, query data from the physical node via HTTP/WS, and create raw transactions; also integrating with PayPal and Stripe checkout and payment+ Develop fee service which estimates fee and tracking dynamic fee change from opensource such as Etherscan, Bitcoin fees + Develop discovery service which tracks the health of each physical nodes from cluster nodes service to query data depend on discovery health check + Contribute to developing core order service base on state pattern + Contribute to developing role management service base on RBAC pattern+ Develop notify forwarder and filter service which supports: - Rescan blocks/transactions if re-organization happen (this is an optional backup method cause have already read block slower a specific amount than the network) - Detect failed transactions to unfreeze amount from order service when transactions may be a failure due to duplicate nonce or physical node can not broadcast transactions - Read, filter, and calculate to confirm transactions from the system * Tech: Microservices with Java 8 and Spring IOC; GRPC and Jetty server; JSON RPC and Websocket; Kafka pubsub; Active MQ for handling delay queue; Redis; cluster database build on PostgresSQL, Jenkins, and Kubernetes

+ Develop an API supervises to deposit, automatically move the asset to a cold wallet, and create withdrawal for the exchange market + Create raw transactions for offline signing valuable transactions on the local computer which using uploaded encrypt private key file + Complete list of assets: BTC and family (BSV/BCH), ETH/ETC and ERC20 tokens, NEO and tokens, TRX, TRC10/TRC20 tokens, XRP, LTC, DASH, EOS, ZEC, BNB. + Tech: NodeJS, Kafka, MongoDB

+ Deploy new Distributed Management System (DMS) for enterprise such as Imexpharm pharma, Codupha pharma, CVI pharma, Phuc Vinh pharma, Trung Nguyen International + Maintain integrity system: Local transferring or distributing product to their branch/distributor such as Nam Duoc/Ich Nhan pharma, Pharimexco pharma, OPV pharma, Thien Thao pharma + Supervise sale, warehouse management, and promotion system + Create specific report, using Aspose/JXL; iText/iReport + Analyze and improve performance of the system such as Uploading function, paging function + Research, deploy few securities such as OWASP library, identity cipher, prepared statement * Tech: Java 7 JSP/Servlet, HTML/CSS/Boostrap, JS/jQuery/AJAX, MS-SQL

+ Manage SQL query, fix and debug stored procedure/function as DBA + IT helpdesk, manage user who links with their software assigned by manager + Improve and create new module or report such as: Customer order, local transfer for making a future schedule + Research, investigate, and analyze for improving warehouse management * Tech: VB, C#, MS-SQL