Omar U. Espejel

Cryptography Engineer & Former AI ML Engineer · Starknet Foundation

Rust engineer implementing state-of-the-art cryptographic primitives and privacy protocols. Previously scaled AI adoption at Hugging Face, the leading open-source AI company.

Current Work

Cryptography & Privacy Engineering

• Maintainer of Starknet Agentic — Infrastructure for AI agents on Starknet with verifiable computation (57 GitHub stars)
• Monero-Starknet Atomic Swaps — Trustless cross-chain swaps using ED25519 MSM verification and DLEQ proofs in Cairo/Rust. No bridges, no KYC.
• Starknet Stealth Addresses — Privacy-preserving payments via one-time unlinkable addresses (Cairo)
• Starknet Privacy Toolkit — Tongo private donations + Noir/Garaga verified donor badges
• STWO Receipts on Solana — Starknet-grade proofs anchored on Solana for private access control (Rust)
• ERC-8004 Cairo — Native Cairo implementation of the ERC-8004 registry standard
• Organizing Re{define} Hackathon (Feb 2026) — $27K prize pool, Bitcoin + Privacy + Open tracks

Track Record

Starknet Foundation (Current)

Senior Developer Advocate Engineer · Cryptography Engineer

• Led Starknet Book to 800+ GitHub stars — the canonical resource for Cairo developers
• Organized Re{solve} Hackathon from scratch — onboarded 1000s of developers, 2x participants and 2x submissions vs previous editions
• Delivered technical workshops at ETHCC, Devcon, ETHPrague on Cairo, ZK, and anti-censorship infrastructure
• Secured ~$75K USD in grants (Ethereum Foundation + Obol Collective) for Restake Watch
• Building privacy infrastructure: Tongo integration, ZK attestation toolkit, stealth addresses, atomic swaps

Hugging Face (Previously)

Machine Learning Engineer / Developer Advocate

• Created 4 top-rated AI courses on Platzi — 5-star avg across 325+ reviews
• Authored core ML educational content: embeddings guide, model fine-tuning, fastai integration
• Scaled NLP/Transformers adoption at the world's leading open-source AI company through hands-on tutorials and documentation

Key Impact: Led developer adoption across two technical ecosystems — Starknet (cryptography/ZK) and Hugging Face (AI/ML) — through production code, technical content, and community building.

Featured Projects

• Monero-Starknet Atomic Swaps — Trustless cross-chain swaps with ED25519 + DLEQ proofs (Cairo, Rust)
• Starknet Agentic — Infrastructure for AI agents with verifiable computation (Cairo, TypeScript, Python)
• Starknet Book — The canonical Cairo/Starknet developer resource (800+ ★)
• Starknet Stealth Addresses — Privacy-preserving payments (Cairo)
• Starknet Privacy Toolkit — Tongo + Noir/Garaga verified private donations (Cairo, TypeScript)
• STWO Receipts on Solana — Starknet-grade proofs on Solana (Rust)
• Restake Watch — Independent Ethereum restaking monitor (~$75K grants)
• ERC-8004 Cairo — ERC-8004 registry standard in Cairo

Recent Talks & Workshops

• Escape Hatches: Urgent Anti-Censorship Solutions — ETHCC 2024, Brussels
• Devcon Bangkok — Starknet workshops and technical sessions
• ETHPrague — Cairo and ZK development workshops
• Monero Talk — Atomic swaps without bridges or KYC
• Monerotopia 2026 — Monero-Starknet atomic swaps: Bridging privacy chains
• ETHKyiv 2024: Starknet is Ethereum's answer to Solana
• HackFS 2024: What will you build on Starknet

Education (Hugging Face Era)

Platzi AI Courses — 4 top-rated courses

• Introduction to NLP with Hugging Face
• Sentence Transformers and Embeddings
• Model Fine-tuning
• fastai Integration

5-star average across 325+ student reviews

Selected Publications

• The Hitchhiker's Guide to Scaling Bitcoin with STARKs (Substack)
• Getting Started With Embeddings (Hugging Face Blog)
• Train and Fine-Tune Sentence Transformers Models (Hugging Face Blog)
• Welcome fastai to the Hugging Face Hub (Hugging Face Blog)