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Andrei Popa

Lead Full-Stack Engineer
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Bucharest, Romania
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linkedin.com/in/pax-x
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github.com/pax-k
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andrei@fastmail.com
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+40 727 133 337

Experienced full stack engineer with over 12 years of expertise in building apps. Successfully raised $3M as the tech lead at Hypercent and contributed to Kin's $4M fundraising efforts during the tenure.

Skills

  • Frontend (ReactJS/NextJS)
  • Backend (NodeJS/NestJS)
  • Mobile (react-native + Expo)
  • DevSecOps (Kubernetes, Nomad, Terraform, Ansible, CI/CD pipelines, SAST, DAST)
  • Blockchain (Solidity, infrastructure)
  • Security (vulnerability assessment)
  • Identity (DID / VC)
  • AI (LLMs, agent orchestration)

Open to positions:

✅ consulting ✅ senior engineer ✅ CTO

About

⚡️ Full Stack Engineer with over a decade of professional experience. 🧙 Shines in building MVPs & strong foundations, validating ideas, solving hard & constrained problems 👷🏻‍♂️ Consulting for the Romanian Government, addressing challenges of strategic importance. 🥷🏻 Certified in Offensive Security with a notable history as a teen hacker. 🤔 Actively exploring the latest protocols, patterns, and software paradigms with a discerning perspective. 💪🏻 Confident in tackling any challenge. Able to solve any problem or learn any language or framework, viewing solutions as a function of time, skill, and passion. Leveraging LLMs for enhanced capabilities.

Work Experience

Garden Computing

Fullstack Engineer
Aug 2024 - May 2025

Jazz.tools is an open-source TypeScript toolkit for building apps with distributed state, making local-first applications mainstream. Jazz simplifies 90% of traditional app stack while providing local-first storage, cross-device sync, real-time multiplayer, and end-to-end encryption.

Highlights:

  • Enhanced core library functionality and performance across distributed state management, improving reliability and developer experience for the open-source community.
  • Developed create-jazz-app CLI tool for streamlined project scaffolding across environments, libraries, and auth methods.
  • Implemented Jazz framework bindings for VueJS and React Native + Expo, expanding platform compatibility and ecosystem adoption.
  • Built Metamask authentication system enabling Web3 wallet-based onboarding and decentralized identity management.
  • Designed multiple storage adapter architectures supporting various persistence backends for flexible deployment scenarios.
  • Delivered critical improvements and bug fixes across monorepo, maintaining code quality and stability.
  • Created official example apps and starter templates for multiple platforms, providing production-ready reference implementations.
  • Architected a production-ready Linear clone demonstrating Jazz's real-time collaborative capabilities and complex state patterns.
  • Implemented agentic AI workflows for automated code generation, streamlining development and improving productivity.
  • Contributed to key company apps: user dashboard, Waffle (Discord clone), and Inspector (debugging tool).
  • Enhanced** CI/CD **with Vercel optimizations, Nomad deployments, and backup systems for improved reliability.
  • Conducted R&D: React Native passkeys in WebViews, AI agents, and MCP server implementation.
  • Provided technical support to community and enterprise clients, fostering ecosystem growth.
  • Authored technical documentation and developer guides, improving onboarding and reducing support overhead.

Tech Stack: TypeScript, NodeJS, React, React Native (Expo), Nomad

Dec 2023 - Dec 2024

As the tech consultant for the Minister of the Romanian Ministry of Investments and European Projects, the role involves aiding the Minister in decision-making. This is achieved by engaging in ongoing national tech projects of interest, gaining a thorough understanding of these projects, and providing guidance to all involved parties.

Kin

Senior Architect & Lead Engineer
May 2023 - Aug 2024

Kin is a personal AI designed to enhance private life. Joined the team as the 2nd employee and contributed significantly to its growth. Kin successfully raised $1M from the Danish Government and $3M from cyber.fund.

Main Architectural Features:

  • Local-first
  • Private
  • Multi-platform
  • open-source LLMs

Highlights:

  • Involved in all engineering aspects of the app, from R&D, to deployment and monitoring.
  • Built a robust codebase with a focus on Developer Experience (DX) and best practices.
  • Established CI/CD workflows using GitHub Actions and EAS Build for our mobile app and libraries.
  • Implemented end-to-end tests using Maestro.
  • Developed an on-device inference service using local AI models, ONNX and Transformers.js for vector embeddings and speech-to-text.
  • Created and published an Expo module (Swift + Kotlin) for audio playback, utilized for text-to-speech.
  • Developed an Expo module (Swift + Kotlin) as a wrapper around CozoDB, used for storing vector embeddings.
  • Published an abstract-level implementation of AsyncStorage for React Native using TypeScript.
  • Packaged our core capabilities as an isomorphic JS SDK, consumed by clients in various environments (react-native, nodejs, web).
  • Implemented AI agent patterns like ReAct, CoT, RAG, using LangChain.js or plain TS.
  • Developed AI agents for various tasks including triplets extraction, reasoning, tool usage or search.
  • Contributed to open-source projects from our stack, either with bug reports, bug fixes, or new features, helping us move forward
  • Otherwise fixing problematic dependencies by forking, patching or polyfilling
  • Set up observability and instrumentation using OpenTelemetry and Grafana.
  • Built a smart local job queue with recurring tasks, locks, and retry on failure or timeout mechanisms, triggered by user inactivity.
  • Implemented backup and restore functionality for user data.
  • Developed an interactive graph visualisation of the AI agent’s memory
  • Benchmarked various libraries or AI models for performance.
  • Delivered various UX & performance optimisations, improving FPS, time to main screen, time of first token
  • Built lots of POCs for various technologies and scenarios, to figure out our next steps. Researched and leveraged Decentralized Identifiers (DIDs), **Decentralized Web Nodes **(DWN), and Trusted Execution Environments (TEE).
  • Always available to help others

Tech Stack: TypeScript, React Native (Expo), NodeJS, Azure

Hypercent

Co-Founder, Tech Lead
Dec 2021 - May 2023

Hypercent is the largest launchpad on the Kadena blockchain, enabling startups to raise over $3M through our crypto crowdfunding platform.

Highlights:

  • Developed the infrastructure and hosted the official Kadena node. Leveraged Hasura on top of the node, to listen for specific on-chain events and to expose the chain data via GraphQL.
  • Created Hypercent’s official crypto wallet.
  • Authored smart contracts to implement our business logic.
  • Built backend services to interact with the smart contracts.
  • Developed the crowdfunding platform
  • Maintained a robust monorepo hosting our wallet, website, backend, libraries, and tools.
  • Developed various tools to enhance the engineering’s team productivity.
  • Led a team of 4 developers to achieve business objectives.

Tech Stack: TypeScript, NestJS, NextJS, Pact-lang

Ronin

Lead Full-Stack Engineer
May 2021 - Dec 2021

Ronin is a fiat crowdfunding platform for startups. Responsibilities included building the platform from the ground up.

Highlights:

  • Led a team of 3 developers.
  • Designed and built the architecture powering the platform.
  • Successfully launched the platform in production, which immediately started funding startups.

Qualitest

Full-stack Engineer
Sep 2020 - Dec 2021

Qualitest is a leader in software outsourcing, catering to the needs of prominent clients such as Elbit Systems and Cellebrite.

Elbit Systems:

  • Industry: Military technology and defense contractor.
  • Highlights: Developed various features for a cyber intelligence platform.

Cellebrite:

  • Industry: Digital intelligence for law enforcement.

  • Highlights:

    • Developed a Docker container orchestration and monitoring tool, providing the platform with 100% control and visibility into its processes.
    • Successfully delivered a complex reporting system for operational and system data, aiding shareholders in making better decisions.

Tech Stack: TypeScript, AngularJS, NestJS, Docker

Genesis Digital

Frontend Engineer
Dec 2019 - Aug 2020

Genesis offers two premier products:

  1. Kartra: An industry-leading marketing SaaS that integrates Customer, Email, Video, Affiliates, Pages, Campaigns, and Shopping Cart management into a single suite.
  2. WebinarJam: "The most dramatic improvement to Live Casting, Event Streaming, and Webinar Broadcasting ever released to the public."

Highlights:

  • Enhanced the features and usability of Kartra’s no-code web page builder, benefiting over 100k users.
  • Successfully reduced the loading time for more than 500k web pages by at least 1 second.

Tech Stack: ES6, VueJS

TailPath

Full-stack Engineer
Mar 2019 - Oct 2019

TailPath is a B2B SaaS supply chain management platform that facilitates the blockchain pairing of data assets with physical products.

Highlights:

  • Managed and extended the existing admin panel and API written in PHP.
  • Rewrote parts of the API in NodeJS for improved performance and scalability.
  • Developed the core business idea by creating a system for pairing data assets with blockchain transactions.
  • Successfully developed and implemented an access control system used in NATO's largest medical exercise in history.
  • Created and launched a blockchain-powered clothing donation mobile app, which was spotlighted by the UK Embassy in Bucharest.

Tech Stack: React Native, NodeJS, PHP, Solidity

888

Frontend Engineer
Feb 2018 - Dec 2019

888 is an international sports betting and gambling company.

Highlights:

  • Enhanced the features and usability of 888’s main poker game.
  • Successfully developed a modern web poker game from scratch, providing the company with a competitive edge.
  • Designed the app's architecture based on product requirements.
  • Translated designs into React components.
  • Conducted R&D and created various Proofs of Concept (POCs) to determine the best technical approaches, such as choosing canvas over DOM for game rendering.

Tech Stack: TypeScript, ReactJS, Redux, KonvaJS, AnimeJS, Styled-components

Findie

Full-stack Engineer
Feb 2017 - Jan 2018

Findie is a London-based startup specializing in generating ideal video summaries from full-length videos.

Highlights:

  • Developed new features and enhanced the usability of the white-label video platform.
  • Successfully delivered custom features for premium clients such as L’Oreal New York and MotoGP.

Tech Stack: React, Reflux, SASS, NodeJS

Ama Mobile

Full-stack Engineer
Sep 2016 - Feb 2017

AMA Studios, a branch of Ubisoft, develops mobile games. Responsibilities included building an admin panel to manage games, developers, and payments.

Highlights:

  • Led front-end and back-end development of admin panel features.
  • Developed a unified API integrating multiple payment systems.
  • Created a unified API for integrating multiple affiliate systems.
  • Built a unified API for integrating various analytics and reporting systems.

Tech Stack: PHP with Symfony3, JavaScript, MySQL, Bootstrap

Arimatrix

Full-stack Engineer
Apr 2016 - Sep 2016

Arimatrix.com is a startup dedicated to helping people gain deeper insights into themselves. Responsibilities included building an app to compile psychological profiles of users.

Highlights:

  • Translated designs into React components.
  • Developed the API using Express, deployed on AWS Elastic Beanstalk with DynamoDB for data storage.

Tech Stack: React, Express, AWS Elastic Beanstalk, DynamoDB

Sandline

Full-stack Engineer
Nov 2015 - Apr 2016

Sandline is a cyber security company. Responsibilities included developing in-house cyber security products.

Highlights:

  • Developed a SaaS platform to handle cyber incidents for companies operating SCADA equipment, such as oil refineries, nuclear power plants, and electric grid operators.
  • Created a SaaS platform to manage GPS devices over 3G, including functionalities like geofencing, alerts, and asset tracking.

Tech Stack: PHP with Codeigniter, JavaScript, Bootstrap

Cestrin

Full-stack Engineer
Feb 2015 - Jul 2016

CESTRIN is the Center of Informatics Studies within the Romanian National Road Company. Responsibilities included developing a reporting system to collect and analyze the status of nationwide infrastructure projects.

Tech Stack: PHP, JavaScript, MySQL, Bootstrap, D3.js

Harpocrates Netsec SRL

Founder
Sep 2012 - Sep 2015

Founded a solo software development company as a student, generating $100k in revenue over 3 years by building custom web applications for various private and public institutions.

Volunteering

Aug 2017 - Oct 2017

The Center for Advanced Strategies is a Romanian think-tank specializing in training on intelligence, security, and geopolitics. Delivered lectures on cybersecurity and OSINT.

Association for Advanced Technologies

Tech Consultant
May 2020 - Mar 2021

The Association for Advanced Technologies is a Romanian NGO dedicated to addressing some of Romania's most significant challenges.

Contributions:

  • Provided tech consultancy for various public institutions.

Ministry of Finance

Tech Consultant
Aug 2020 - Mar 2021

Successfully launched the national system for monitoring and surveillance of fiscal data collected from all cash registers in Romania.

Tech Stack: Go, RabbitMQ, Kubernetes (k8s), React

Oct 2023 - Current

The "International Economic Intelligence" postgraduate program, offered by the Center for Advanced Strategies and the Academy of Economic Studies, is a transdisciplinary course focused on competitive intelligence, strategic analysis, and decision-making. It aims to equip participants with advanced tools for market analysis, business optimization, and strategic thinking in the international economic environment.

Contribution:

  • Annually present a course on OSINT techniques.

Projects

react-native starter

Next-gen react-native development monorepo starter with best in-class tools tailored for DX⚡️https://github.com/pax-k/pax-react-native-starter

Education

Faculty of Engineering in Foreign Languages - Computer Science - Polytechnic University of Bucharest

Bachelor's
Oct 2011 - Oct 2013

Dropout

Offensive Security

Offensive Security Certified Professional (OSCP)
Jul 2015 - Jul 2015

OSCP is the most well-recognized and respected certification for info security professionals. An OSCP, by definition, is able to identify existing vulnerabilities and execute organized attacks in a controlled and focused manner, write simple Bash or Python scripts, modify existing exploit code to their advantage, perform network pivoting and data ex-filtration, and compromise poorly written PHP web applications.

Conferences

Defcamp
Defcamp is the largest cybersecurity conference from CEE. I attended the conference each year since 2011, but I haven’t held a presentation yet.

Hobbies

- translating books