# Sergey Tolsi Tolmachev

> Sergey Tolmachev (known as Tolsi) is a software architect and CTO with 12+ years of experience building distributed systems, blockchain infrastructure, and early-stage products. He is open to CTO and tech lead engagements.

## Professional Identity

- Fractional CTO and software architect specializing in blockchain, distributed systems, and Web3
- Built btcpay.ru — the first Bitcoin-to-ruble exchange service in Russia (2012)
- Lead analyst and engineering leader across fintech, DeFi, and creative tech
- Public speaker on blockchain technology (Waves 3.0 Meetup 2019; blockchain masterclass 2018)
- Podcast guest on engineering leadership (Blum Chats, 2025, EN)
- Scala, Rust, Kotlin, Python, Go, Java developer

## Disciplines

Software Architecture, Blockchain Development, Distributed Systems, Research and Development, Prototyping, Deployment, Technical Leadership, DevOps, Embedded Systems, Smart Contracts, Cryptography

## Selected Work

- btcpay.ru — first Bitcoin-to-ruble exchange in Russia (2012)
- Terra support (terra.support) — metaphoric associative card platform (2020–present)
- Defragmentation — visual artwork exhibited in Moscow (2023)
- Release.space — art space and cafe in Tbilisi (2023–2024)

## Public Talks

- Blum Chats podcast — working as a lead analyst (2025, EN): https://youtu.be/sG_eol3IVb8
- Waves 3.0 Meetup — cryptographically verified Niva car giveaway (2019, RU): https://youtu.be/Ts5pPBncBb8?t=2261
- Blockchain development masterclass (2018, RU): https://www.youtube.com/watch?v=czyABHsoJH4
- Pro Bitcoin podcast episode 48 (2017, RU): https://www.youtube.com/watch?v=FKqiGvRrSLo

## Contact

- Site: https://tol.si
- Email: tolsi.ru@gmail.com
- LinkedIn: https://www.linkedin.com/in/tolsi
- GitHub: https://github.com/tolsi
- Telegram: https://t.me/tolsi1
- CV: https://tol.si/assets/_Tolmachev_CV_08_2025.pdf