Gwanho Lee (Tony) | Backend Engineer

Profile

Backend engineer focused on complex networked systems, system-level reliability, incident response, and practical service impact.

Experienced in problem solving across backend, distributed, and system-level concerns. Strong ownership in architecture analysis, reliability improvement, and production-grade service delivery.

Open Source Contributions

Recent PRs in Mithril focused on API expansion, signer stability, and safer client tooling.

Mithril (input-output-hk/mithril) - Rust Contributor

Rust Contributor | Dec 2025 - Present | Protocol Engineering & Architecture

Implemented v2 REST routes for Cardano proofs and added STM negative signature tests (PR #3005, PR #2985).
Fixed signer runtime failures around KES edge cases and SQLite panic paths (PR #2952, PR #2953, PR #2940).
Improved client reliability with streaming downloads and safer verification-report writes (PR #2899, PR #2921).

Featured Project

Personal Bitcoin wallet project with multisig and Lightning testnet workflows.

Rust Bitcoin CLI Wallet (Multisig + Lightning)

Architecture & Development | Sep 2025 - Dec 2025

Repo: leepl37/rust_cli_wallet | Demo: YouTube

Built a non-custodial wallet with BIP39/32 HD derivation, multisig transactions, and Lightning integration via LDK.
Published technical notes and demo videos to explain architecture choices and implementation details.

Professional Experience

Built and operated backend services across public event systems and national identity services.

Lead Backend Engineer - JTS (Join Together Society) Youth Festival

Seoul, South Korea | Feb 2025 - Nov 2025

Project: YouthFesta.com | Repos: Festa-Apply, SMS-Proxy

Designed and led backend architecture for an event platform that handled 6,000+ registrations and 3,000+ live check-ins without service disruption.
Built and operated an SMS proxy service to improve verification delivery reliability during peak traffic windows.
Owned production operations and incident handling to maintain zero downtime throughout the event period.

Backend Software Engineer - KOMSCO (Korea Minting, Security Printing & ID Card Corp)

Daejeon, South Korea | Oct 2021 - Feb 2025

Project: Government Mobile Identification System (Mobileid.go.kr)

Developed backend modules for national mobile ID services, implementing secure QR authentication flows (CPM/MPM).
Reduced production issue recovery time by using observability-driven debugging across API and verification pipelines.

Backend Developer - Itro (Automated Parking Management System)

Daegu, South Korea | Feb 2021 - Oct 2021

Integrated IoT sensors with gate-control hardware through REST APIs to stabilize real-time parking operations.
Implemented testable time-based billing logic and shipped performance-focused sprint deliverables.