You're seeing this page as if you were . The main menu is still yours, though. Exit from immersion
Johan Alexis Duque CadenaJA

Johan Alexis Duque Cadena

Senior Software Engineer

€312/day
Terrassa, ES
8-15 years

Average response time: 1 hour

About Johan Alexis

I help companies build reliable Rust software for backend systems, embedded Linux, blockchain infrastructure, and security-sensitive products.

I am a Senior Rust Software Engineer with experience delivering production software across Web3, automotive, embedded systems, and self-hosted infrastructure. I usually work on Rust backend services, async APIs, gRPC/GraphQL integrations, Substrate/Polkadot SDK development, custom pallets, runtime upgrades, blockchain node automation, Linux-based platforms, Dockerized services, and secure authentication flows with WebAuthn/passkeys, JWT, TLS/mTLS, HSMs and cryptographic signatures.

What makes me different is that I can move comfortably between backend architecture, low-level Linux, blockchain infrastructure, networking, DevOps, and security. I also use AI deeply and responsibly in my workflow for research, planning, debugging, code review, automation and documentation, while validating the output and avoiding low-quality AI-generated code.

Typical deliverables I handle include Rust microservices, backend APIs, CLI tools, blockchain tooling, Substrate pallets, node automation, embedded Linux integrations, CI/CD improvements, observability with Prometheus/Grafana, and technical problem solving for complex systems.
  • Spanish

    Native or bilingual

  • Catalan

    Conversational

  • English

    Fluent

Can work on-site
Terrassa (up to 20km)

Experience

  • Kunveno
    Senior Software Engineer
    July 2025 - Today (11 months)
    • • Develop blockchain and backend solutions based on Polkadot SDK, including runtime logic, pallets, and decentralized modules.
    • • Build Rust backend middleware for onboarding Web2 users into Web3 applications and blockchain-based workflows.
    • • Design and maintain smart contract development environments for rapid prototyping, testing, and integration.
    • • Develop ink! smart contracts and integrate contract-layer functionality with runtime and backend components.
    • • Use AI-assisted research, planning, debugging, and implementation review as part of a responsible engineering workflow.
    Rust Bash Linux Docker Blockchain
  • Virto
    Senior Software Engineer - Rust Blockchain Engineer
    March 2025 - Today (1 year and 3 months)
    • • Develop Rust-based Polkadot pallets and maintain parachain runtimes aligned with Polkadot SDK.
    • • Implement decentralized authentication flows using passkeys, WebAuthn, JWT, and non-custodial identity concepts.
    • • Build Rust tooling for blockchain automation, wallet interaction, transaction signing, and runtime testing.
    • • Use subxt for typed interaction with Substrate-based chains and automated extrinsic submission.
    • • Work on runtime upgrade flows, proof-of-concept implementations, and integration testing across blockchain components.
    • • Contribute to FOSS projects across the Polkadot ecosystem, including Parity, Encointer, and ink! Alliance.
    Rust Linux GitHub Continuous integration Blockchain
  • G6
    Senior OS Engineer
    February 2024 - March 2025 (1 year and 1 month)
    • • Designed and built a customized GNU/Linux distribution based on Debian using Live Build.
    • • Managed blockchain nodes across distributed infrastructure, focusing on availability, reliability, and security.
    • • Developed Rust and Linux tooling for blockchain interaction, extrinsics automation, and operational workflows.
    • • Designed and deployed self-hosted CI/CD solutions to improve release and DevOps efficiency.
    • • Implemented OS testing with QEMU/KVM to validate system stability across environments.
    Debian Rust Linux Blockchain Back-End development

Recommendations

Be the first to recommend Johan Alexis

Help this freelancer shine by sharing your experience working together.

These freelancer profiles also match your criteria

AgathaA

Agatha Frydrych

Backend Java Software Engineer

4.7

(3)

2

BaptisteB

Baptiste Duhen

Fullstack developer

4.6

(4)

5

AmedA

Amed Hamou

Senior Lead Developer

4

(2)

7

AudreyA

Audrey Champion

Web developer

4.3

(3)

4

Education

  • MSc in
    Universitat Politecnica de Valencia
    2014
    MSc in
  • Electronics Engineer
    Universitat Politecnica de Valencia
    2012
    Electronics Engineer

Skill set

Categories