Octavian Lojnita
Verified Expert in Engineering
Full-stack Developer
Constanța, Romania
Toptal member since April 22, 2022
Octavian, an accomplished software polymath, has 20+ years of experience in networking, security, apps, websites, blockchains, and emerging technologies like AI. His expertise in app development, iOS games, custom web systems, and fintech propelled numerous projects to success in both the Web 2.0 and Web 3.0 realms. Leveraging his profound knowledge, Octavian pushes the frontiers of blockchain technologies, fostering innovation within all his expertise.
Portfolio
Experience
Availability
Preferred Environment
Solidity, Blockchain, Next.js, React, TypeScript, Decentralized Finance (DeFi), DApps, Fintech, Security Audits, Fuzz Testing
The most amazing...
...thing I've built is one of the first fee-less blockchains in 2018 and non-custodial libraries and protocols for fields, such as DeFi, gaming, and gambling.
Work Experience
Chief Technical Officer
Progressive Web Apps
- Developed back-end and front-end solutions for clients that required KYC and AML expertise. I developed the back end in Node.js and the front end in React.
- Built ERC20 tokens, ERC677 tokens for multiple clients, and ICO campaigns with multistage vesting emissions. In the past year, we focused on building DAOs and voting systems in which proposers, voters, and executers maintain the community treasury.
- Helped a few local artists launch their independent and ERC721 NFT collections. A few of the NFTs provided access to a private website section that allowed only private members to join.
- Built multiple projects that used ERC721 and ERC1155 to incentivize a private community focused on DAO governance.
- Developed solutions that revolved around Chainlink and APIs to ensure on-chain whitelisting and revalidation for existing members.
- Integrated Chainlink Price Feeds into multiple ICOs to provide full conversion in USD for every major supported cryptocurrency. This ensured strict USD limits that were compliant with KYC and AML rules.
- Contributed to the Loom Network interoperable bridges and universal wallets.
- Integrated more than 30 non-custodial wallets inside front ends.
Chief Technology Officer, Blockchain
Psalm, LLC (dba Psalm DAO)
- Reduced ERC721 smart contract IT costs to around 13 MATIC on Polygon to mint 20,000 NFTs.
- Lowered gas fees to around 0.0005 MATIC for the same batch of 20,000 NFTs after upgrading the codebase to ERC721A.
- Helped configure and deploy Next.js and Vercel for the website.
- Managed two teams and mentored developers on using the Ethereum virtual machine (EVM) to help them use newer EVM tricks more efficiently to reduce gas costs.
Blockchain Expert
Opus Momentus Proprietary Limited
- Built a fully functional cross-chain hedge with six core features: wallet creation, staking, deposits, relayer, aggregator, and withdrawal.
- Created the back end and fault tolerance using two mirror databases: relational and non-relational.
- Developed deposit tracking using Alchemy SDK and deposits aggregator contracts deployed on each chain.
Blockchain Expert
Hoichi
- Developed a Solidity smart contract for Hoichi DAO to distribute prizes incurred from the Hoichi Token Uniswap buy and sell fees to their 369 ERC-721 NFT holders.
- Built the raffle to support the Chainlink VRF self-subscription method.
- Tested on Sepolia, simulated on Mainnet, and created the deployment configuration.
- Deployed the raffle to Ethereum Mainnet successfully.
- Passed all audits with flying colors—no issues found.
Blockchain Lead
Freelance Client
- Discovered multiple critical vulnerabilities and logic flaws in multiple projects that the team was working on and helped protect and migrate liquidity to safe versions.
- Created a thorough security report detailing the problems discovered and mitigation steps with scenario outcome recommendations.
- Rewrote the v1 codebase into the most gas-efficient version with native MEV Protection.
- Innovated trading protection features and OTC Token sales. Led auditing, testing, deployments, and liquidity migrations that covered all edge cases and successfully migrated all vulnerable liquidity using flashbots and shielded transactions.
- Added protected transactions to prevent MEV bots from executing a sandwich attack on users by draining their slippage tolerance.
- Added a check that enforces multi-transfers only to be done once per block by each user when transferring and thus prevented MEV bots from making arbitrage and transaction reordering plays.
- Performed a lot of planning, rewrites, dead code, and improved gas costs to the latest versions with no technical debt.
- Made a snapshot of balances for V1 and minted an equal amount in V2 contracts.
- Helped coordinate with team members and assisted them in creating local forks and Gnosis treasury proposals, votes, and quorum executions via Flashbots.
- Trained three developers on how to do mainnet fork and simulations. Created scripts to extract liquidity and do the migrations successfully.
Expert Smart-contract Blockchain Developer
Freelance Clients
- Created MultiCall contracts, tests, and protected transactions.
- Handled Alchemy scripts and Flashloans private transactions relayed to the Flashbots bundlers to minimize MEV Bots from reading the transactions in the memory pool and doing frontrunning, sandwich attacks, arbitrage, and flash loans.
- Built forks, setups, tests, and local fork simulations.
Senior Full-stack Developer
Fii pe net
- Trained five junior colleagues, which allowed us to reduce deployment times and increase productivity.
- Built and maintained a big data real estate data scraper that made cross-referenced filters for the LIFA Denmark API using TypeScript.
- Developed numerous WordPress websites and maintained their security.
- Handled SEO growth hacks and ensured our audit coverage was always up to date.
API Developer
AWC LLC
- Developed the front end and integrated wallets using BitGo APIs that enabled crypto payments within the platform.
- Started an experiment that turned into a non-custodial wallet by building a PIN-password lock/unlock feature that allowed discovery and self-recovery of the private key using the Curve25519-based algorithm.
- Built the API that handled the Magento and Shopify plugins and open-source plugins used by developers to handle big data processing for payment solutions.
- Owned full responsibility for development environments and product deployments.
iOS App Developer
iSecurity LLC
- Built an app using Objective-C with video, audio streaming, and access to CCTV cameras that displays employee schedules and tracks and audits schedules.
- Managed multiple clones of the same app for different clients, increasing management and productivity while making time-consuming tasks easy to perform.
- Took responsibility for auditing every update before publishing.
- Helped developers ship faster by maintaining environments and ensuring tight security.
Experience
Bitcoin Lottery
https://demo.btclottery.ioIn 2016, I ended up with a centralized version due to my lack of knowledge. The original version, which I didn't like, was never made public. Bitcoin was $250 at that time. As years passed, new blockchain technologies constantly rechallenged me to rethink and rebuild. I joined the sidechain hype in its early days in 2017 and set out to improve speed and eliminate costs for permissionless environments. These environments couldn't be spammed and could be feeless while always allowing creators to create their own token distribution mechanisms that automatically rewarded their userbases with the help of Chainlink VRF and Chainlink Keepers. The current version uses a DPOS model with a maximum of 21 modes, similar to the Binance Smart Chain.
Randomizer Network
https://randomizer.networkStore Payment Processor
https://sfpy.coJoystick Gaming
https://joystickgaming.io/I did a security audit and discovered a critical vulnerability and helped save and migrate their existing liquidity that was vulnerable and went unnoticed by multiple top auditors. Additionally, I rewrote the Joy Token and xJoy Token, added on-chain MEV protection, created the Presale contract with a live AMM OTC sale which sends xJoy to the user, and created a Claim Page using React + Next.js + Typescript in which users could see all their calculations for the 8 months cliff + 3 years linear vesting releases of the OTC.
Finally, I helped their team become better and more efficient by learning how to fork Ethereum Mainnet.
Dough Finance
https://dough.financeWorld Liberty Financial
https://worldlibertyfinancial.comEducation
Bachelor's Degree in Economics
Universitatea Tomis - Constanta, Romania
Bachelor's Degree in Computer Science
Universitatea Ovidiu - Constanța, Romania
Skills
Libraries/APIs
React.js, Node.js, Web3.js, JSON-RPC, REST API, API Development, Vue.js, Binance API
Tools
MetaMask, GitHub, VPN, Jira, Etherscan, VirtualBox, Sequelize, Geth (go-ethereum)
Languages
Solidity, JavaScript, HTML, CSS, TypeScript, Fantom, SQL, HTML5, SCSS, Go, Solidity Assembly, Objective-C, C, C++, Assembly, Python, GraphQL
Frameworks
Next.js, Hardhat, Express.js, Tailwind CSS, Truffle, Cosmos SDK
Paradigms
DevOps, API, Microservices Development, Fuzz Testing, Microservices Architecture, Distributed Computing, Scrum Master Consulting, Agile Development, Agile Development, Interoperability
Platforms
Blockchain, Ethereum, Chainlink, Blockchain, Decentralized Exchanges (DEXs), AWS, Twilio Development, DigitalOcean, Oracle Development, MultiChain, Kubernetes, Linux, KVM, Vercel, Netlify, Avalanche, Mobile App Design, iOS, WordPress Development
Industry Expertise
Virtual Coaching, Cybersecurity, Banking Consulting
Storage
NoSQL, Database, PostgreSQL, Redis, JSON, MongoDB, MySQL
Other
BNB Smart Chain, Tokenomics, QA Testing, NFT, Payment APIs, APIs, Cryptocurrency, ICO, ERC677, Smart Contract Development, Ethereum Smart Contract, ERC-721, Decentralized Applications, Fintech Development, Decentralized Finance (DeFi), Cryptocurrency Wallets, Blockchain & Cryptocurrency, Ethers.js, Blockchain, Decentralized Autonomous Organizations (DAO), DApps, Full-stack, Security, Architecture, ERC-1155, Audits, Team Leadership, Infrastructure, IT Infrastructure, Crypto, Software Development, Decentralization, Flash Loans, Integration, API Integration, Decentralized Systems, Software Architecture, Consensus Mechanism, Tokenization, Quality Assurance Engineering, QA Leadership, QA Testing, Manual QA, Utility Tokens, Technical Leadership, Technical Requirements, Estimations, Web 3.0, ERC-20, RPC, WebSockets, P2P, Advisory, Project Consultancy, Networks, Web Development, Algorithms, Software Engineering, Front-end, Web Development, Financial Software Development, Interim CTOs, Leadership, Digital Asset Management, Exchanges, Fractionalization, Cryptocurrency Exchanges, Admin Panels, Back-end Developers, Blockchain as a Service, Parsers, Compilers, Web3, Casinos & Gaming, Gambling, Public Finance, Back-end Developers, Product Growth, Foundry, Web Scraping, Mobile App Design, Token Design, Database, Ledgers, Off-chain Development, Troubleshooting, Auditing, ÐApp, Marketplace Design, CI/CD Pipelines, Scripting, Ethereum Virtual Machine (EVM), Full-stack, Applied Cryptography, Test Scripting, token airdrop, Distributed Ledger Technology (DLT), White Papers, Computer Science, Crytographer, Technical Writing, Mobile App, Data Science, Front-end Development, UI Development, UX Development, UTXO, Cryptocurrency APIs, Data Science, Blockchain Architecture, Mathematics, Large Scale Distributed Systems, Distributed Software, Vendor Management, Algorithms, Uniswap, Uniswap V2, Uniswap SDK, Trading Bots, Liquidity Pools, cross chain, Swaps, Aggregators, Binance Smart Chain (BSC), Automated Market Makers (AMM), Subgraph, Base Blockchain, Payment Gateways, Payment Processing, Economics, Finance, Bitcoin, Web Development, Games, IT Security, IPFS, Blockchain Game Development, Distributed Systems, Team Management, Scrum Master Consulting, Polygon, Memory Pools, Bots, Trading, Healthcare Services, WebAssembly, Biomedical Skills, Chrome Extension Development, Arbitrum, Content Writing, Writing & Editing, Sidechains, Design, Universal Wallet, Blocknative, Arbitrage, Lottery, Security Audits, GRAPH, iOS Games, Smart Contract Auditing
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