Available for work

Hey, I'm Juan
Sheinix 👋

Engineer. Creator. Builder in crypto, web3, and AI. I ship real products that solve real problems — and this is where I share the work, the ideas, and the journey. Argentine roots, New Zealand based.

Let's build together →
Juan at workspace

Stay in the loop

Weekly thoughts on crypto, AI, and building in public. Short reads, no fluff, no spam.

What I'm doing right now

Last updated: May 11, 26

🧉

MateFAI

Your DeFi agent, in your language. MateFAI reads your wallet, analyzes your DeFi positions, and recommends better yields — all in plain Spanish (or English), no jargon. Currently in private beta across LATAM.

Content Creation

Crypto, blockchain, and DeFi content in Spanish on YouTube for 70k+ subscribers. Breaking down complex web3 and AI topics so anyone can understand them.

Holdii

Holdii

A programmable coordination layer for digital wealth. Set rules for when and how your crypto assets release — inheritance, vesting, milestones — all on-chain, no middlemen. Multi-chain across Ethereum, Base, Polygon, and more.

Selected Works

Products and tools I've built — shipping real things that solve real problems.

🧉

[matefai]

AIDEFILATAM

MateFAI

Your DeFi agent, in your language. MateFAI reads your wallet, analyzes your DeFi positions, and recommends better yields — all in plain Spanish (or English), no jargon. Currently in private beta across LATAM.

Private BetaVisit →
Holdii preview
CRYPTOSOLIDITYDEFI

Holdii

A programmable coordination layer for digital wealth. Set rules for when and how your crypto assets release — inheritance, vesting, milestones — all on-chain, no middlemen. Multi-chain across Ethereum, Base, Polygon, and more.

LiveVisit →
The GitGazette preview
AIOPEN SOURCENEXTJS

The GitGazette

AI-powered newsroom for open-source repos. Paste any GitHub URL and get satirical-but-informative coverage from five fictional columnists — drama, code reviews, shipping forecasts, and more.

LiveVisit →
SignalBoard preview
Archived
CRYPTONEXTJSPOLYMARKET

SignalBoard

UMA resolution risk tracker for Polymarket. Identified high-risk markets before they disputed. A great learning experience building real-time data products — no longer maintained.

ArchivedVisit →

Experience

15+ years building software across mobile, blockchain, data, and web — from Oracle databases to multichain wallets.

Full-timeMay 2023 - May 2026

Senior Software Engineer

Easy Crypto / Swyftx

New Zealand, Remote

Blockchain Engineer architecting a multichain MPC wallet for EVM and UTXO networks. Overseeing client integration, backend services, node providers, and Hardhat-based smart-contract development. Drove the technical implementation of New Zealand's NZDD stablecoin.

BlockchainSolidityMPC WalletsHardhat
Self-employedMar 2022 - 2024

Founder

Sheinix Academy

Metaverse

Building an educational platform focused on crypto, blockchain, and Web3 development. Community development and online marketing.

CommunityEducationMarketing
Full-timeAug 2022 - May 2023

Software Specialist

ASB Bank

New Zealand, Remote

Software infrastructure and architecture specialist working on banking software systems.

Software ArchitectureInfrastructure
Self-employedFeb 2018 - 2022

iOS Freelance Developer & Blockchain Writer

Freelance

Auckland, NZ

Freelance iOS developer for various projects and clients. Consultancy on mobile development and UX/UI design. Blockchain writer at CoinMonks publication.

iOSSwiftUX/UITechnical Writing
Full-timeSep 2018 - Jan 2022

iOS Developer

Accedo.tv

Auckland, NZ

Developed iOS applications for the OTT/streaming platform serving major media companies worldwide.

iOSSwifttvOSStreaming
Self-employedOct 2020 - Mar 2021

Co-Founder

El Token Newsletter

Buenos Aires, Argentina

Co-founded a Spanish-language crypto newsletter covering DeFi, blockchain developments, and market analysis.

CryptoContentNewsletter
Personal ProjectJul 2018 - Oct 2020

iOS Developer

Kiwi Slang App

Auckland, NZ

Personal open source project — an app for learning New Zealand slang. Published on the App Store.

iOSSwiftOpen Source
Side ProjectNov 2017 - Oct 2020

iOS Lead Developer

Smart Backpacker App

Barcelona, Spain

Not-for-profit project assisting backpackers and travelers. In charge of iOS design, development and maintenance on the App Store.

iOSSwiftUI Design
Full-timeFeb 2017 - Feb 2018

iOS Lead Developer

Mascoteros

Barcelona, Spain

Led architecture, development, testing and management of the Mascoteros iOS app from inception to release. CI/CD pipeline management.

iOSSwiftCI/CDArchitecture
Full-timeMar 2014 - Apr 2015

iOS Developer

Etermax

Buenos Aires, Argentina

Developed in Objective-C, participating and leading work on a new chat app. Worked with Apple frameworks, REST services and XMPP technologies.

Objective-CRESTXMPP
Full-timeDec 2011 - Mar 2014

Analyst Programmer

Indra

Argentina

ETL development with Unix ShellScripting and Data Integrator. SAS modules implementation. Oracle BPM application development and maintenance. Java services and SQL Server development.

PL/SQLETLJavaOracle BPM
Full-timeAug 2009 - Sep 2011

Analyst Programmer

Telecom Argentina

Argentina

BI team delivering high quality reports. Analysis and developments in Microsoft SQL Server, PL/SQL and BI tool Qlikview.

PL/SQLSQL ServerQlikviewBI
Full-time2008 - 2009

PL/SQL Developer

Oracle

Argentina

PL/SQL and APEX framework development for Oracle client-server applications. Database management with Oracle 9i and 11g.

PL/SQLOracle APEXDatabase

Skills & Tech Stack

BlockchainSoliditySmart ContractsDeFi / Web3MPC WalletsHardhatAI / LLMsiOS / SwiftReact NativeTypeScriptObjective-CRustPL/SQLJavaNext.jsReactNode.jsREST APIsCI/CDETLOracle BPMSQL ServerUX/UI DesignSoftware ArchitectureContent CreationCommunity BuildingProduct

Blog

Building in public — writing about crypto, AI tools, and the things I learn shipping real products.

Read all posts→
Apr 10, 2026•3 min read
ETHEREUMPOST-QUANTUMGOVERNANCE

Ethereum's Post-Quantum Problem Isn't the One You Think

Quantum computers breaking Ethereum's signatures isn't the hard part. The real challenge is migrating dormant wallets whose owners will never sign.

Read more →
Apr 3, 2026•6 min read
AAVEDEFILENDING

Aave V4 Is Live. Here's What Actually Changed.

Aave V4 launched on Ethereum mainnet with the biggest architecture change in its history — a Hub and Spoke model that finally lets liquidity flow where it's needed.

Read more →
Mar 27, 2026•5 min read
ETHEREUML2DEFI

EEZ Explained: The Plan to Reunite Ethereum (And What It's Going to Break)

Rollups solved scaling but fragmented Ethereum. The Ethereum Economic Zone proposes synchronous composability to fix it — here's what that means and what it breaks.

Read more →
Mar 20, 2026•4 min read
AIOPEN SOURCE

Why Changelogs Suck and How I Built 6 AI Journalists to Fix Them

GitHub activity is exploding. Changelogs are dry, release notes incomplete, notification feeds unreadable. So I built Git Gazette — six AI columnists with personalities that turn raw repo activity into a newspaper you'd actually want to read.

Read more →
Mar 20, 2026•3 min read
PERSONALNEWSLETTER

I Owe You an Apology

I promised I'd keep writing and disappeared for a year. Here's why I stopped, what changed, and what to expect from here.

Read more →
Mar 15, 2026•4 min read
BUILD LOGAI

Shipping a GitHub AI Tool as a Solo Dev: The 7-Day Build Log

I built Git Gazette in a week. Here's the day-by-day breakdown — proof of concept, character prompts, the GitHub API, Stripe integration — and what it taught me about the new bottleneck for solo devs: not coding, but knowing what to spec.

Read more →
→More postsView all 7 articles

Products & Links I Use

Tools and services I actually use and recommend. Some links are referral codes — full transparency.

👻

Aave Wallet

DeFi lending & borrowing protocol wallet

💳

RedotPay

Crypto-to-fiat card for everyday spending

🛡️

Ledger Nano

Secure hardware wallet for cold storage

🔒

Trezor Safe3

Open-source hardware wallet

⚔️

Cypherock X1

Shamir-based MPC hardware wallet

🔐

HashWallet

Biometric hardware wallet — code: SHEINIX2024

🔑

OneKey Classic

Affordable hardware wallet

🔵

Crypto.com

Exchange crypto + app

🔶

Binance

Leading crypto exchange

💳

Tangem Wallet

Card-shaped hardware wallet — code: CRYPTOSHEINIX (10% off)

🧾

Koinly

Crypto tax reporting made simple

🦈

SurfShark VPN

Privacy VPN — 30 days free

🦁

Brave Browser

Privacy-focused browser with ad blocking

Let's Stay in Touch

Always open to interesting conversations about crypto, AI, design systems, or just geeking out over good coffee.

Telegram

@sheinix

YouTube

@cryptosheinix

Twitter/X

@sheinix

Juan Sheinix

Juan Sheinix

Crafting digital spaces since 2019

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