David Molnar — software · hardware · Bitcoin · open source

Software, hardware, and Bitcoin privacy tools.

Senior software engineer with 15+ years building software, 8 of them on Bitcoin privacy. Former CTO at Wasabi Wallet, now an independent contractor on Ginger Wallet, Fetaphon, TESCO, AGIS, and more. Budapest, Hungary.

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What I do

Bitcoin node and hardware wallet on a dark desk
01 — Bitcoin

Bitcoin — development, privacy, mentoring

8 years of active Bitcoin development since 2018. Wasabi ex-CTO and CoinJoin protocol work. Privacy, security, non-custodial.

 Multi-monitor developer workstation with code editors
02 — Software

Software engineering

.NET, C#, plus the surrounding stack — desktop, client-server, web, hardware/API integration. Team mentoring and open source.

 PCB, partly disassembled handheld device, oscilloscope and soldering tools
03 — Firmware

Firmware & embedded

ESP32, STM32, Atmel, nRF52. Bluetooth modules, displays, MP3 chips, SD card. Battery-powered handhelds.

 Electrical cabinet with control modules and a wall-mounted touch panel
04 — Smart home

Smart home & electrical

Home Assistant, Homey, Zigbee. Homes and building automation, remote access, monitoring, AI.

 Enclosed 3D printer printing an industrial bracket, with filament spools and calipers
05 — 3D printing

3D printing & industrial parts

Bambu X1C printing up to 1,000-piece runs. Multi-color, PLA, PETG, ASA, ABS, carbon and glass fiber.
01

Bitcoin — development, privacy, mentoring

Active Bitcoin developer since 2018. Six years at Wasabi Wallet as core contributor and CTO — 4,600+ commits, deep work on the CoinJoin protocol. Now lead developer on Ginger Wallet. Focus: privacy, security, and non-custodial solutions. Typical services for clients: wallet generation and safe seed-phrase storage, hardware wallet onboarding (Trezor, Coldcard, Ledger), Bitcoin buy / sell / conversion to fiat (exchanges and non-custodial options), sending and receiving, CoinJoin via Ginger Wallet and Wasabi Wallet, Bitcoin acceptance support for merchants, Lightning, and full node setup. Mentoring from beginners (how to store, buy, which wallets to choose, what to watch out for) to power users.

02

Software engineering

15+ years as a software engineer. Primary stack: .NET and C# — Avalonia desktop apps, ASP.NET Core backends, distributed systems. Comfortable across desktop, client-server, web, and hardware/API integration. Familiar with C++, Rust, Python, TypeScript, Swift, JavaScript, and shell where the job needs it. Mentoring developers, leading small teams, project management. Open-source contribution is something I care about — mainly Bitcoin privacy projects (Wasabi, Ginger, NBitcoin, WabiSabi), but I am open to other meaningful open-source work.

03

Firmware & embedded

Custom firmware design and development from PCB schematics, plus modification of existing firmware. Microcontroller experience: ESP32, STM32 (Atollic TrueStudio toolchain), Atmel, nRF52. Bluetooth module programming, display drivers for handheld devices, MP3 chip integration, SD card storage. Battery-powered handhelds with displays, audio playback, and Bluetooth. Tight integration of electronics and firmware. Concrete products: the Fetaphon medical device for expecting mothers (a handheld fetal heartbeat monitor), audio guide devices, desktop and handheld wellness products, and bioresonance hardware.

04

Smart home & electrical

Electrical work and smart home device installation and integration. Home Assistant and Homey systems for both homes and building automation, with Zigbee as the primary mesh. Remote access, monitoring, automations, and AI integration into the system. Typical jobs: a full smart-home layer for new construction, or retrofitting an existing home.

05

3D printing & industrial parts

3D printing on a Bambu X1C, up to 1,000-piece runs. Multi-color printing in PLA, PETG, ASA, ABS, carbon-fiber, and glass-fiber filaments. Custom part design and replacement manufacturing with real tolerances — gears, enclosures, brackets. Marketing object design and production: fridge magnets, keychains, branded items, promo pieces.

Selected work

Former CTO ↗
W

Wasabi Wallet

Former CTO

Wasabi Wallet

Open-source Bitcoin privacy wallet. Six years as core contributor and CTO, 4,600+ commits, deep CoinJoin protocol work.
Lead developer ↗
G

Ginger Wallet

Lead developer

Ginger Wallet

Privacy-first Bitcoin wallet. Open source. Currently the architecture and core engineering.
Firmware & hardware ↗
F

Fetaphon

Firmware & hardware

Fetaphon

Medical device for expecting mothers — a battery-powered, handheld fetal heartbeat monitor. Full schematic and firmware.

Independent contractor
T

TESCO

Independent contractor

TESCO

Software development and engineering consulting for a European retail giant.

Independent contractor
A

AGIS

Independent contractor

AGIS

Security-systems integration work for enterprise clients.

Wasabi Wallet — Open-source Bitcoin privacy wallet. Six years as core contributor and CTO, 4,600+ commits, deep CoinJoin protocol work.

Ginger Wallet — Privacy-first Bitcoin wallet. Open source. Currently the architecture and core engineering.

Fetaphon — Medical device for expecting mothers — a battery-powered, handheld fetal heartbeat monitor. Full schematic and firmware.

TESCO — Software development and engineering consulting for a European retail giant.

AGIS — Security-systems integration work for enterprise clients.

About

I’m David Molnar, a senior software engineer based in Budapest. 15+ years building software — distributed systems, embedded hardware, and (since 2018) Bitcoin privacy tools. I spent six years at Wasabi Wallet, eventually as CTO, building one of the most widely used Bitcoin privacy wallets — 4,600+ commits across the protocol and client. Today I work as an independent contractor on several parallel projects, including Ginger Wallet, Fetaphon, TESCO, and AGIS. I take on hard problems: protocol-level Bitcoin privacy, battery-powered embedded devices that have to run for years, and industrial parts with real tolerances.

Elsewhere

Get in touch

Open to interesting collaborations, consulting, and conversations. English or Hungarian.

Email [email protected]
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