Stephen Antoni builds backend systems for crypto exchanges, DeFi protocols, and quantitative trading firms — custody, signing, smart contracts, and execution, engineered for reliability where failure is expensive.

End-to-end backend development across four specialized domains — each built for production scale from day one.
Full-stack blockchain middleware from node integration to multi-chain wallet systems. Reliable deposit and withdrawal flows engineered for exchange-grade uptime and operational accountability.
Custom ICP, Solana, and EVM-compatible contract development with custom PDA account models and production-grade backend APIs that bridge on-chain logic with external systems — Rust, Solidity, and middleware layers included.
High-performance execution systems for forex, commodities, and equities. From sub-millisecond scanners to full backtesting frameworks and risk management modules — built in Rust, C++, Python, and MQL4.
Applied ML for financial signal generation — LSTM price predictors, reinforcement learning traders, NLP sentiment engines, and full feature pipelines from data to prediction API deployment.
Production-hardened languages and tooling across systems programming, backend services, and financial automation.
Eight case studies across custody, signing, contracts, quant research, machine learning, execution, and mining operations.
Custodial wallet service for multi-chain deposits, pooled wallets, and outgoing transfers, built with stable APIs and layered signing controls.
Blockchain infrastructure, trading automation, or AI-driven financial systems — scope the work, then deliver it right.