StJohn is available for hire

StJohn Piano

Verified Expert in Engineering

Blockchain Developer

Location

Valencia, Spain

Toptal Member Since

November 15, 2022

StJohn is a highly-skilled and motivated senior software engineer with 11+ years of experience, 8+ of which have been in the blockchain industry. He currently works as the head of engineering at Solidi Cryptocurrency Exchange. StJohn has built excellent software for a fully regulated UK cryptocurrency exchange, a blockchain-based web publishing system, a secure Bitcoin storage toolset, a speech recognition company, a transcription team, and a furniture factory.

Security Bitcoin Cryptocurrency Back-end Web3 Algorithms Python Linux Blockchain Ethereum Express.js Solidity Full-stack MySQL Git Digital Electronics Crypto Wallet Gunicorn Ripple Integrated Circuits

Portfolio

MRZ Labs Limited

Back-end, Sequelize, TypeScript, Express.js, MySQL, Node.js, Smart Contracts...

Solidi

Bitcoin, Blockchain, JavaScript, Node.js, Python, MySQL, Cryptocurrency...

CoinX24 AG

Blockchain, Python, APIs, Ethereum Smart Contracts, Smart Contracts, Ethereum...

Experience

Python - 12 years MySQL - 10 years Linux - 10 years Bitcoin - 8 years Blockchain - 8 years Fabric - 6 years JavaScript - 3 years Node.js - 3 years

Availability

Part-time

Preferred Environment

Linux, Python, Node.js, MySQL, NGINX, Gunicorn, JavaScript, TypeScript, Docker, Blockchain

The most amazing...

...thing I've developed is a ready-for-production Ethereum smart contract project template, written in Solidity, Hardhat, and TypeScript.

Work Experience

Back-end Engineer

2023 - PRESENT

MRZ Labs Limited

Implemented API testing to confirm that information flowed correctly into the database.
Completed detection and storage of blockchain events on the raffle smart contract.
Wrote a good logging system for the application—it can write to a console and optionally to a file with JSON-formatted lines. It is set up to transport logs to an external application with a 30-day rolling window.

Technologies: Back-end, Sequelize, TypeScript, Express.js, MySQL, Node.js, Smart Contracts, Blockchain, Solidity, Ethers.js, Web3, Web 3.0

Head of Engineering

2021 - PRESENT

Solidi

Designed, implemented, tested, and completed the Solidi trading app on iOS and Android.
Upgraded the Solidi system to a major new operating system version.
Ensured internal software for regulatory compliance, including customer risk scoring and Chainalysis integration, enabling Solidi to pass the UK Financial Conduct Authority registration requirements, which was very unusual for a crypto company.

Technologies: Bitcoin, Blockchain, JavaScript, Node.js, Python, MySQL, Cryptocurrency, Vim Text Editor, Visual Studio Code (VS Code), GitHub, DigitalOcean, Smart Contracts, Ethereum Smart Contracts, Ethereum, Solidity, Security, Blockchain & Cryptocurrency, React, HTML, Arbitrage, Software Architecture, Technical Leadership, Decentralized Systems, Technical Requirements, Architecture, Estimations, DApps, Blockchain Platforms, Decentralized Autonomous Organizations (DAO), Tokenomics, APIs, PHP, TypeScript, Docker, Cryptocurrency Wallets, Crypto, Express.js, Ethers.js, Back-end, SQL, Oracle, Web3, Web3.js, Bots, Trading, Algorithms, Full-stack

Blockchain and Full-stack Developer

2023 - 2023

CoinX24 AG

Developed smart contracts to receive pseudonymous private payments.
Developed a Python package to deploy, manage, and retrieve information from the smart contracts.
Developed a Hardhat testing package to test the smart contracts.

Technologies: Blockchain, Python, APIs, Ethereum Smart Contracts, Smart Contracts, Ethereum, Tether (USDT), Node.js, Hardhat, Web3, Web 3.0, ERC-20

Software Engineer

2019 - 2022

Edgecase

Designed and implemented a Bitcoin toolset. The code is available at Github.com/sj-piano/bitcoin_toolset_python3, with more background information at Edgecase.net/pages/how_to_store_bitcoin. The code is pure Python 3 and includes excellent logging.
Built and implemented a web application for interacting with the Edgecase Datafeed blockchain. It is, in effect, a block explorer with fully automated deployment via Fabric and dev/staging and production servers and pinpoint-accurate logging.
Created and implemented Edgecase Datafeed, a secure publishing system. All published articles are digitally signed and timestamped in the Bitcoin blockchain.

Technologies: Bitcoin, Python, Fabric, DigitalOcean, NGINX, Gunicorn, Cryptocurrency, Pytest, Vim Text Editor, GitHub, Security, Blockchain & Cryptocurrency, HTML, Arbitrage, Software Architecture, Technical Requirements, Architecture, APIs, Crypto, Express.js, Ethers.js, Back-end, SQL, Web3, Amazon Web Services (AWS)

Software Engineer

2019 - 2021

Solidi

Implemented support for new cryptocurrencies in the Solidi exchange application, including Ethereum (ETH), Ripple (XRP), and Cardano (ADA).
Designed and implemented secure cold storage solutions for ETH, XRP, and ADA. Wrote recipes for their use.
Implemented a trading bot that bought and sold cryptocurrency on other exchanges.
Implemented Secure Sockets Layer (SSL) secured RabbitMQ messaging to handle communication between various cryptocurrency clients and the main system.
Designed and implemented a new version of the Solidi trade engine. It uses Kafka to handle order or trade messaging.

Technologies: Bitcoin, Blockchain, Node.js, JavaScript, MySQL, RabbitMQ, Ethereum, Cardano, Ripple, Apache Kafka, Git, Python, Fabric, Cryptocurrency, GitHub, Vim Text Editor, Visual Studio Code (VS Code), DigitalOcean, Smart Contracts, Ethereum Smart Contracts, Security, Solidity, Blockchain & Cryptocurrency, React, HTML, Software Architecture, Technical Requirements, Architecture, Estimations, APIs, PHP, Crypto, Back-end, SQL, Web3, Bots, Trading, Algorithms

Project Manager

2015 - 2019

Abacii

Managed 17 transcription projects, totaling 336,738 transcriptions. Transcribed speech data are used to test the accuracy of speech recognition systems.
Hired and trained new transcribers. Wrote an accompanying transcription guide, which can be viewed at arkaeologic.pythonanywhere.com/faq/default.
Wrote scripts to perform proofreading, spellchecking, and statistical selection for quality assurance (QA) testing on transcription projects. The average raw text accuracy score was 92.1%.
Wrote scripts to process large Nuance Recognizer logs and extract data for transcription.
Learned how to install, configure, and use a Nuance Recogniser system in a CentOS VM. Implemented speech grammar systems in English and Spanish.
Ported Excel VBA macros for project report generation to new versions of Excel.

Technologies: Python, Project Management, Excel VBA, Nuance Recognizer, Software Architecture, Technical Leadership, Technical Requirements, Estimations, Back-end

Software Engineer

2014 - 2015

Jali

Implemented a plug-and-play Raspberry Pi-based networked camera system. Takes and serves a 1296x972 pixel JPEG file over a local network in around 0.5 seconds. Three of these cameras were installed in the Jali automated furniture painting system.
Implemented Raspberry Pi-based dynamic control of a Baldor motion controller and Omron servomotors.
Helped to construct and test a prototype automated 3D woodworking machine.

Technologies: C, Arduino, Raspberry Pi, Python, HTML, PHP, Back-end

Experience

A Ready-for-production Ethereum Smart Contract Project Template

https://github.com/sj-piano/ethereum-smart-contract-project-template-typescript

A ready-for-production Ethereum smart contract project template, written in Solidity and Typescript. It pre-calculates all gas fees in ETH and USD, includes a complete Hardhat test suite, and can deploy to Sepolia testnet and Ethereum mainnet.

Deep Dive into Bitcoin Address Generation

http://edgecase.net/articles/generating_a_standard_bitcoin_address

A deep investigation into the generation of standard Bitcoin addresses, all the way back to the official ECDSA document published by the Accredited Standards Committee X9. It includes a comprehensive description of the generation algorithm and my notes on the nature, secure creation, and validity of Bitcoin private keys and transactions. The project log at the end of the article is long and can be skipped.

Edgecase

http://edgecase.net/pages/start_here

A Python-based blockchain for publishing with a web app for exploring the chain, i.e., viewing articles. I developed the blockchain, back end, and front end. Some articles are checkpoints, which are block headers for each set of new articles. Checkpoint articles are hashed and timestamped in the Bitcoin blockchain, making all previously published articles and digital assets immutable.

Review of the Ledger Nano S

http://edgecase.net/articles/review_of_the_ledger_nano_s_hardware_wallet

My review of the Ledger Nano S hardware wallet. I advise making some adjustments to the standard approach in order to store bitcoin on it as securely as possible. Includes some notes on Segregated Witness (SegWit) addresses and their downsides.

Education

2011 - 2012

Master's Degree in Electrical Engineering

Durham University - Durham, United Kingdom

2008 - 2011

Bachelor's Degree in Electrical Engineering

Durham University - Durham, United Kingdom

2005 - 2007

International Baccalaureate (IB) Diploma in Mathematics and Physics

American School of Madrid - Madrid, Spain

Skills

Libraries/APIs

Node.js, Fabric, React, Web3.js

Tools

NGINX, GitHub, Vim Text Editor, Git, CAD, RabbitMQ, Pytest, Sequelize

Frameworks

Express.js, Hardhat

Languages

Python, Solidity, JavaScript, HTML, PHP, TypeScript, SQL, VHDL, Java, C, Excel VBA

Platforms

Linux, Blockchain, Ethereum, DigitalOcean, Blockchain Platforms, Amazon Web Services (AWS), Cardano, Apache Kafka, Arduino, Raspberry Pi, Visual Studio Code (VS Code), Docker, Oracle

Industry Expertise

Project Management

Storage

MySQL, Databases

Other

Bitcoin, Cryptocurrency, Smart Contracts, Ethereum Smart Contracts, Security, Blockchain & Cryptocurrency, Software Architecture, Cryptocurrency Wallets, Crypto, Ethers.js, Back-end, Web3, Bots, Trading, Algorithms, ERC-20, Gunicorn, Pyenv, Arbitrage, Technical Leadership, Decentralized Systems, Technical Requirements, Architecture, Estimations, APIs, Non-fungible Tokens (NFT), Web 3.0, Full-stack, Programming, Digital Signal Processing, Digital Electronics, Embedded Systems, Mechanics, Analysis, Integrated Circuits, Differential Equations, Field-programmable Gate Arrays (FGPA), Signal Theory, Thermodynamics, Electric Power Systems, Analytics, Dynamic Systems Modeling, Communication Protocols, Cellular Automata, French, Networks, Devices, Ripple, Nuance Recognizer, Mathematics, Physics, Chemistry, Spanish, History, English, Cadence, DApps, Decentralized Autonomous Organizations (DAO), Tokenomics, FPGA, Tether (USDT)

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