Profile Photo
Andrzej Broński

Senior Software Engineer

Developer with 4+ years of professional Rust experience – fascinated by crypto and building fast, reliable systems.
Make it work • Make it right • Make it fast
koxu1996@gmail.com
t.me/andrzej1_1
bron.ski
github.com/koxu1996
linkedin.com/in/andrzej1k1
medium.com/@koxu1996
Kraków, Poland (UTC+2)

Proof of excellence

Silk
BTC → XMR atomic swaps
Built & operated solo
Self-custodial and fully in-browser: no custodian, no server-side keys, swaps settle atomically. A reimplementation of the Eigenwallet protocol, with a live liquidity dashboard of the makers behind it.
$2M+
live liquidity tracked
Silk dashboard showing total available liquidity, median XMR price, and the first three active makers

Experience

Malda.xyz
Lead ZK Engineer
Dec 2025
–
May 2026
Budapest, Hungary · Remote
Shut down · Apr 2026 (no PMF)
  • Took ownership of a ZK-based cross-chain sequencer project, driving it to mainnet readiness.
Key results:
  • Introduced full zkVM guest reproducibility by nixifying Risc0 – malda/risc0pkgs.
  • Dockerized RPC infrastructure for Ethereum, Linea, Base, and Optimism – malda/atlas.
  • Implemented Linea block verifier for their new consensus model – malda/linea-header-verifier.
  • Established full CI pipeline for the Malda coprocessor codebase: format checks, linting, tests, and reproducible builds.
Rust EVM Nix LayerZero
Gevulot / ZkCloud
Senior Software Engineer
Aug 2024
–
Nov 2025
Helsinki, Finland · Remote
Dropped ZK proving · pivoted to Zenith (Canton)
  • Benchmarking and integrating external ZK provers; writing custom orchestration.
  • Working on Ethereum real-time proving.
Key results:
  • In the first month, won “Aztec Decentralization Contest”, in both categories (US $20,000).
  • Eliminated a bottleneck in Ethereum proving: reduced input preparation from ~4 minutes to 2 seconds, and open sourced solution.
  • Achieved Ethereum real-time proving with a cluster of 48× RTX 4090 and ZisK zkVM, live-tested at Devconnect Argentina (Nov 2025).
Rust Tokio SP1 Risc0 Reth EVM
Casper Network
R&D Engineer
Jan 2023
–
Jul 2024
Zug, Switzerland · Remote
No traction · token down >95% since 2023
  • Building a dedicated L2 for processing payments, using zero-knowledge technology.
  • Assessing grant deliverables.
  • Representing the company at public events.
Key results:
  • Designed L2 system ‘Kairos’ and implemented its core parts: ASN.1-based schema, cryptography, L1 synchronization.
  • Created blockchain library for handling events: Casper Event Toolkit.
  • Reviewed 30+ grant projects and recommended cancellation for many due to grant farming.
  • Performed public speeches: ~ ‘Web3 vs Web2 development’ – Lubelskie Dni Informatyki, university at Lublin. ~ ‘How to quickly start building on Casper?’ – Cryptosphere conference in Wrocław. ~ ‘Dynamic NFTs’ – Web3 Berlin conference.
Rust Tokio Risc0
Next on p. 2 ⟶ JumpWire, Founding Engineer
1 / 2
Profile Photo
Andrzej Broński

Senior Software Engineer

Developer with 4+ years of professional Rust experience – fascinated by crypto and building fast, reliable systems.
Make it work • Make it right • Make it fast
koxu1996@gmail.com
t.me/andrzej1_1
bron.ski
github.com/koxu1996
linkedin.com/in/andrzej1k1
medium.com/@koxu1996
Kraków, Poland (UTC+2)

Experience (continued)

JumpWire (YC W22)
Founding Engineer
Jun 2022
–
Nov 2022
Boston, MA, US · Remote
Acquired by WorkOS · Jan 2024
  • Building MVP – platform for dynamic data access control.
Key results:
  • Implemented REST proxy, configurable via OpenAPI specification file.
  • Fixed binary protocol bug, where type was incorrectly converted.
  • Implemented rediscovery of DB schema, handling potential conflicts.
Elixir Phoenix PostgreSQL Rust Git Tailwind Svelte
Microsoft Ireland
Software Engineer II
Aug 2021
–
Nov 2021
Dublin, Ireland · Hybrid
  • Enhancing security of Azure Cloud infrastructure.
  • Creating new security monitors, using C# and KQL.
Key results:
  • Analyzed and documented 50+ security rules; gathered knowledge from 3 different teams.
  • Fixed silent-failure defects in ~20 monitors.
  • Introduced health-check dashboard; discovered several repeatedly failing monitors.
C# KQL Power BI
ESET Polska
Specialized Software Engineer
Nov 2019
–
Jul 2021
Kraków, Poland · On-site
  • Developing a new platform for fuzz-testing antivirus modules.
Key results:
  • Developed cross-platform worker node in C++.
  • Created REST fuzzing service for Endpoint product – on the first run it found +10 unique crashes.
  • Adjusted PDF module to cross-compile with ASan – discovered 2 memory bugs.
C++ CMake Boost Python Django PostgreSQL Docker ZMQ
Securitum
Penetration Tester
Sep 2017
–
Sep 2018
Kraków, Poland · On-site
  • White-hat hacking web and mobile applications.
  • Static code analysis.
  • Writing security reports in accordance with OWASP ASVS framework.
Key results:
  • Won “bug of the month” prize, for exploiting Java deserialization bug – full RCE, even before client prepared test account.
  • Found critical vulnerability in a major Polish bank.
  • Wrote Java Deobfuscator for ZKM 5 – used to extract app secret key.
Burp Suite Arch Linux Python Java Docker
Freelancing
Web Developer
2014 – 2017 · Dec 2021
–
May 2022
Nowy Sącz / Kraków, Poland · Remote
  • Creating full-stack web projects, either for individual clients or for contracting company.
Git PHP Yii Laravel MySQL Redis JavaScript TypeScript React

Education

AGH University of Science and Technology
Kraków, Poland
Jan 2019 – Dec 2020
Master’s degree in Computer Science
Autoscaling of computations in container clouds.
AGH University of Science and Technology
Kraków, Poland
Oct 2015 – Jan 2019
Bachelor’s degree in Computer Science
Modern web applications penetration testing.
2 / 2
Profile Photo
Andrzej Broński

Senior Software Engineer

Developer with 4+ years of professional Rust experience – fascinated by crypto and building fast, reliable systems.
Make it work • Make it right • Make it fast
koxu1996@gmail.com
t.me/andrzej1_1
bron.ski
github.com/koxu1996
linkedin.com/in/andrzej1k1
medium.com/@koxu1996
Kraków, Poland (UTC+2)

Proof of excellence

Silk
BTC → XMR atomic swaps
Built & operated solo
Self-custodial and fully in-browser: no custodian, no server-side keys, swaps settle atomically. A reimplementation of the Eigenwallet protocol, with a live liquidity dashboard of the makers behind it.
$2M+
live liquidity tracked
Silk dashboard showing total available liquidity, median XMR price, and the first three active makers

Experience

Malda.xyz
Lead ZK Engineer
Dec 2025
–
May 2026
Budapest, Hungary · Remote
Shut down · Apr 2026 (no PMF)
  • Took ownership of a ZK-based cross-chain sequencer project, driving it to mainnet readiness.
Key results:
  • Introduced full zkVM guest reproducibility by nixifying Risc0 – malda/risc0pkgs.
  • Dockerized RPC infrastructure for Ethereum, Linea, Base, and Optimism – malda/atlas.
  • Implemented Linea block verifier for their new consensus model – malda/linea-header-verifier.
  • Established full CI pipeline for the Malda coprocessor codebase: format checks, linting, tests, and reproducible builds.
Rust EVM Nix LayerZero
Gevulot / ZkCloud
Senior Software Engineer
Aug 2024
–
Nov 2025
Helsinki, Finland · Remote
Dropped ZK proving · pivoted to Zenith (Canton)
  • Benchmarking and integrating external ZK provers; writing custom orchestration.
  • Working on Ethereum real-time proving.
Key results:
  • In the first month, won “Aztec Decentralization Contest”, in both categories (US $20,000).
  • Eliminated a bottleneck in Ethereum proving: reduced input preparation from ~4 minutes to 2 seconds, and open sourced solution.
  • Achieved Ethereum real-time proving with a cluster of 48× RTX 4090 and ZisK zkVM, live-tested at Devconnect Argentina (Nov 2025).
Rust Tokio SP1 Risc0 Reth EVM
Casper Network
R&D Engineer
Jan 2023
–
Jul 2024
Zug, Switzerland · Remote
No traction · token down >95% since 2023
  • Building a dedicated L2 for processing payments, using zero-knowledge technology.
  • Assessing grant deliverables.
  • Representing the company at public events.
Key results:
  • Designed L2 system ‘Kairos’ and implemented its core parts: ASN.1-based schema, cryptography, L1 synchronization.
  • Created blockchain library for handling events: Casper Event Toolkit.
  • Reviewed 30+ grant projects and recommended cancellation for many due to grant farming.
  • Performed public speeches: ~ ‘Web3 vs Web2 development’ – Lubelskie Dni Informatyki, university at Lublin. ~ ‘How to quickly start building on Casper?’ – Cryptosphere conference in Wrocław. ~ ‘Dynamic NFTs’ – Web3 Berlin conference.
Rust Tokio Risc0
Next on p. 2 ⟶ JumpWire, Founding Engineer
1 / 2
Profile Photo
Andrzej Broński

Senior Software Engineer

Developer with 4+ years of professional Rust experience – fascinated by crypto and building fast, reliable systems.
Make it work • Make it right • Make it fast
koxu1996@gmail.com
t.me/andrzej1_1
bron.ski
github.com/koxu1996
linkedin.com/in/andrzej1k1
medium.com/@koxu1996
Kraków, Poland (UTC+2)

Experience (continued)

JumpWire (YC W22)
Founding Engineer
Jun 2022
–
Nov 2022
Boston, MA, US · Remote
Acquired by WorkOS · Jan 2024
  • Building MVP – platform for dynamic data access control.
Key results:
  • Implemented REST proxy, configurable via OpenAPI specification file.
  • Fixed binary protocol bug, where type was incorrectly converted.
  • Implemented rediscovery of DB schema, handling potential conflicts.
Elixir Phoenix PostgreSQL Rust Git Tailwind Svelte
Microsoft Ireland
Software Engineer II
Aug 2021
–
Nov 2021
Dublin, Ireland · Hybrid
  • Enhancing security of Azure Cloud infrastructure.
  • Creating new security monitors, using C# and KQL.
Key results:
  • Analyzed and documented 50+ security rules; gathered knowledge from 3 different teams.
  • Fixed silent-failure defects in ~20 monitors.
  • Introduced health-check dashboard; discovered several repeatedly failing monitors.
C# KQL Power BI
ESET Polska
Specialized Software Engineer
Nov 2019
–
Jul 2021
Kraków, Poland · On-site
  • Developing a new platform for fuzz-testing antivirus modules.
Key results:
  • Developed cross-platform worker node in C++.
  • Created REST fuzzing service for Endpoint product – on the first run it found +10 unique crashes.
  • Adjusted PDF module to cross-compile with ASan – discovered 2 memory bugs.
C++ CMake Boost Python Django PostgreSQL Docker ZMQ
Securitum
Penetration Tester
Sep 2017
–
Sep 2018
Kraków, Poland · On-site
  • White-hat hacking web and mobile applications.
  • Static code analysis.
  • Writing security reports in accordance with OWASP ASVS framework.
Key results:
  • Won “bug of the month” prize, for exploiting Java deserialization bug – full RCE, even before client prepared test account.
  • Found critical vulnerability in a major Polish bank.
  • Wrote Java Deobfuscator for ZKM 5 – used to extract app secret key.
Burp Suite Arch Linux Python Java Docker
Freelancing
Web Developer
2014 – 2017 · Dec 2021
–
May 2022
Nowy Sącz / Kraków, Poland · Remote
  • Creating full-stack web projects, either for individual clients or for contracting company.
Git PHP Yii Laravel MySQL Redis JavaScript TypeScript React

Education

AGH University of Science and Technology
Kraków, Poland
Jan 2019 – Dec 2020
Master’s degree in Computer Science
Autoscaling of computations in container clouds.
AGH University of Science and Technology
Kraków, Poland
Oct 2015 – Jan 2019
Bachelor’s degree in Computer Science
Modern web applications penetration testing.
2 / 2
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