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
- Full-stack - 14 years
- Blockchain - 11 years
- Ethereum - 8 years
- Solidity - 8 years
- DApps - 8 years
- Audits - 7 years
- React - 7 years
- Decentralized Finance (DeFi) - 5 years
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
Freed Finance
Freed abstracts away blockchain complexity, so users can focus on what matters, with everything they need and nothing they don’t.
FEATURES
• Spend Yield, Keep Crypto
The card that lets you fund purchases with your portfolio growth. Never sell your principal asset unnecessarily.
• Aggregated Liquidity
Retail swaps are often inefficient. Freed aggregates liquidity from top DEXs to give you optimized pricing on every trade.
• The Financial Social Network
Money is social. Freed turns your contact list into a decentralized payment network. Send USD, EUR, or ETH as easily as a DM.
• Smart Portfolio Intelligence
Strategy x402 is an autonomous agent that monitors multi-chain environments to rebalance your portfolio into safe yield opportunities.
• Your Business, On-chain.
Accept payments globally. Settle instantly. Freed lets you create a storefront in seconds. Issue invoices and settle instantly in USDC or USDT directly to your wallet.
• Optimize Your Capital
Idle capital loses opportunity. Freed's Autonomous Vaults automatically route your capital to safe, yield-optimized pools so your net worth grows with every block.
Bitcoin Lottery
https://btclottery.ioIn 2016, I ended up building a centralized version due to my lack of understanding, and the original centralized 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 the early days of 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 old free-to-play versions used Loom Network DPOS Blockchain until 2020, when they decided to change course, which taught me 3rd-party resiliency.
World Liberty Financial
Randomizer Network
Store Payment Processor
Joystick 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
Education
Bachelor's Degree in Economics
Universitatea Tomis - Constanta, Romania
Bachelor's Degree in Computer Science
Universitatea Ovidiu - Constanța, Romania
Skills
Libraries/APIs
React, Node.js, Web3.js, JSON-RPC, REST APIs, API Development, Vue, AirDrop, Plaid API, Crypto++, Common Crypto, OpenZeppelin, Stripe, Protobuf, Web3.py, Binance API
Tools
MetaMask, GitHub, VPN, Jira, Etherscan, VirtualBox, Remix IDE, Plaid, Ethereum Plasma, Terraform, Prisma, Slack, Google Workspace, Zapier, Claude, Claude Code, VMware, Oracle Configure, Price and Quote (CPQ) Cloud, Sequelize, Geth (go-ethereum), Drift
Languages
Solidity, Go, JavaScript, HTML, CSS, TypeScript, Python, Fantom, SQL, GraphQL, HTML5, SCSS, Rust, C++, Solidity Assembly, PHP, Objective-C, C, Assembly, Java
Frameworks
Next.js, Hardhat, Express.js, Tailwind CSS, Truffle, gRPC, Anchor, NestJS, Redux, Jest, Cosmos SDK
Paradigms
DevOps, API Architecture, Microservices, Fuzz Testing, Microservices Architecture, Distributed Computing, Agile Software Development, Application Architecture, Continuous Integration (CI), Concurrent Programming, Event-driven Architecture, Model Context Protocol (MCP), Role-based Access Control (RBAC), Automation, Scrum, Agile, Agile Project Management, Interoperability
Platforms
Blockchain, Ethereum, Chainlink, Blockchain Platforms, Decentralized Exchanges (DEXs), Amazon Web Services (AWS), Twilio, DigitalOcean, Oracle, MultiChain, Kubernetes, Linux, KVM, Bybit, Docker, Google Cloud Platform (GCP), Mapbox, Azure, Amazon EC2, Vertex AI, Robinhood, Vercel, Netlify, Avalanche, Mobile, Red Hat Linux, iOS, WordPress
Industry Expertise
Project Management, Cybersecurity, Binance Cryptocurrency Exchange, Trading Strategy Development, Banking & Finance, High-frequency Trading (HFT)
Storage
NoSQL, Databases, PostgreSQL, Redis, JSON, Data Pipelines, MongoDB, MySQL
Other
BNB Smart Chain, Tokenomics, Quality Assurance (QA), Non-fungible Tokens (NFT), Payment APIs, APIs, Cryptocurrency, ICO, ERC677, Smart Contracts, Ethereum Smart Contracts, ERC-721, Decentralized Applications, Fintech, Decentralized Finance (DeFi), Cryptocurrency Wallets, Blockchain & Cryptocurrency, Ethers.js, Blockchain Design, Decentralized Autonomous Organizations (DAO), DApps, Full-stack, Security, Architecture, ERC-1155, Audits, Team Leadership, Infrastructure, IT Infrastructure, Crypto, Software, Decentralization, Flash Loans, Integration, API Integration, Trading, Decentralized Systems, Software Architecture, Consensus Mechanism, Tokenization, QA Automation, 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, Webhooks, Stock Exchange, CTO, Leadership, Digital Asset Management, Exchanges, Fractionalization, Cryptocurrency Exchanges, Admin Panels, Back-end Development, Blockchain as a Service, Parsers, Compilers, Web3, Casinos & Gaming, Gambling, Public Finance, Back-end, Product Growth, Foundry, Web Scraping, Push Notifications, Token Design, Data Queries, Ledgers, Off-chain Development, Troubleshooting, Auditing, ÐApp, Marketplaces, CI/CD Pipelines, Scripting, Ethereum Virtual Machine (EVM), Full-stack Development, Applied Cryptography, Test Scripting, token airdrop, Distributed Ledger Technology (DLT), White Papers, Computer Science, Cryptography, Technical Writing, Apps, Quantitative Finance, Front-end Development, User Interface (UI), User Experience (UX), UTXO, Cryptocurrency APIs, Data Science, Blockchain Architecture, Mathematics, Large-scale Distributed Systems, Distributed Software, Vendor Management, Algorithmic Trading, 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, QR Codes, Cryptocurrency Trading, Maximal extractable value (MEV), Documentation, WalletConnect, MEV bots, Maximal Extractable Value (MEV), Lending, Real Estate, Project Budget Management, Project Discovery, NFT Design, Website Integration, Squarespace, Digital Payments, Payment Systems, Payment Solutions, Solana, Solution Architecture, Blockchain Development, Artificial Intelligence (AI), Credit Card Processing, Credit Cards, High-risk Credit Card Processing, PCI DSS, TradingView, Permit2, Code Review, Product Owner, System Architecture, Cloud, Deployment, Platform Engineering, Telegram Bots, AWS Cloud Operations, Performance Optimization, Real-time Data, Hyperliquid, Backtesting, Data Handling, CSV File Processing, Backtesting Trading Strategies, Data Vaults, Health, Identity & Access Management (IAM), Compliance, Google Drive, Email Automation, Card Payments, CRM Systems, SMS Bots, Airtable, Enterprise Architecture, AI Integration, Large Language Models (LLMs), OpenAI, Stablecoins, Metrics, Data Analysis, A/B Testing, Startups, Minimum Viable Product (MVP), Escrow, Hash, Deterministic Encryption, VRF, ERC-8004, Payments, Fractional CTO, Prompt Engineering, LLM Integration, AI Agent Orchestration, AI Agents, Agentic AI, Gemini, Virtual Machines, Networking, Virtual Environments, Unix/Linux Virtualization, Memory Management, Virtualization, AI Security, Data Security, Web Security, App Infrastructure, Cloud Infrastructure, Enterprise Infrastructure, Infrastructure Monitoring, Infrastructure Automation, Immutable Infrastructure, Infrastructure Security, Network Security, Customer Identity and Access Management (CIAM), Capital Markets, Venture Capital, External Audits, Audit Testing, Website Audits, IT Audits, Code Auditing, SEO Audits, Apple Pay, Google Pay, Industrial Automation Communication Protocols, Application State Management, Responsive UI, Zustand, Blockchain Wallets, Monitoring, Transactions, Open-source LLMs, Economics, Finance, Bitcoin, Websites, Games, IT Security, IPFS, Blockchain Game Development, Distributed Systems, Team Management, Scrum Master, Polygon, Memory Pools, Bots, Healthcare Services, WebAssembly (Wasm), Biomedical Skills, Chrome Extensions, Arbitrum, Content Writing, Writing & Editing, Huff, Arweave, Filecoin, Quantitative Risk Modeling, Prediction Markets, Sidechains, Design, Universal Wallet, Blocknative, Arbitrage, Lottery, Security Audits, GRAPH, iOS Games, Smart Contract Auditing, Quantum Computing, Open Banking
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