Staff / Lead Engineer
Oleksii Vasylenko
18 years shipping distributed systems, fintech, and cryptographic products. I work from low-level Rust services through typed SDKs and React interfaces, and I lead teams when the problem needs both architecture and delivery.
Selected results
- 2,400+
- workflow instances/sec
- 4,000+
- orders/sec
- 3×
- order-book depth
- 15
- engineers led
Core capabilities
- Rust, TypeScript, React, Node.js, Solidity
- Distributed systems and durable execution
- Matching engines and real-time market data
- ZK proofs, smart contracts, and applied cryptography
- PostgreSQL, Redis, RabbitMQ, Docker, AWS, GCP
- Architecture leadership across remote teams
Experience
Security Researcher at Independent Security Research
2026 - Present · Remote
- Conducted independent security research on Threshold Network / tBTC, reviewing its distributed threshold-signing client (Go) and bridge contracts (Solidity)
- Identified a quorum-synchronization invariant gap in the protocol's post-signing completion path, where signing-done accounting was not bound to the exact attempt's selected signer set — a protocol liveness / safety-margin (griefing) class issue rather than key, signature, or fund compromise
Go · Solidity · Threshold Signatures (tECDSA) · Bitcoin · Lattice Cryptanalysis · Immunefi
Technical Lead / Full-Stack Developer at Bitsten exchange
June 2024 - Feb 2025 · Remote
- Architected matching engine processing 4000+ orders/sec with sub-millisecond latency
- Engineered liquidity bots integrating multiple market maker APIs, improving order book depth by 3x
React · Node · TypeScript · Nest · RabbitMQ · KeyDB
Web3 Developer at Panther Protocol
June 2023 - June 2024 · Remote
- Built zk-SNARK wallet engine supporting multiple blockchains with UTXO-based transaction model
- Identified and resolved critical vulnerabilities in Circom circuits during security audits
React · Service Workers · zk-STARK · zk-SNARK · Circom · Elliptic Curve Cryptography
Web3 Developer at Mailchain
March 2022 - June 2023 · Remote
- Integrated major blockchains including Ethereum, ENS, and Near for wallet-to-wallet messaging
- Created TypeScript SDKs with comprehensive documentation for third-party developers
React · D3 · Node.js · WebSockets · Ethers · Rollup · Webpack
Frontend Architect at PropertyGuru
April 2020 - March 2022 · Singapore
- Engineered unified payment service adopted across 4 product teams, eliminating duplicate code
- Implemented Webpack Module Federation reducing deployment coupling and release cycle from weeks to days
React · NestJS · D3 · Node.js · Tableau · WebSockets
Head of Product Development at Data Laboratories
August 2015 - December 2018 · Singapore
- Led team of 15 engineers across 3 time zones, shipping on tight deadlines
- Architected D3-based data visualization platform processing millions of data points in real time
React · D3 · WebSockets · .NET Core · CoffeeScript
Earlier work & education
Frontend Architect at ZuZu Hotels · Rust Developer at Kobvel Software Consulting · Senior Full-Stack Developer at Xen Technologies · Full-Stack Developer at Lohika
Bachelor of Computer Engineering with honors, Sevastopol National Technical University · English and Portuguese