Sean Shillo
Verified Expert in Engineering
Full-stack Architect and Developer
San Francisco, CA, United States
Toptal member since May 22, 2020
Sean is a senior full-stack developer and architect who has delivered many web and mobile projects, including ones that needed to be robust enough to process heavy data workloads. He's worked with several front-end and back-end frameworks, including Python, Ruby, JavaScript, TypeScript, Rails, Django, Node.js, and PostgreSQL. Sean's performed both as an individual and as a manager, and he's capable of contributing quickly with little guidance as well as advising on best practices.
Portfolio
Experience
Availability
Preferred Environment
GitHub, Trello, Asana, Slack, Visual Studio Code (VS Code), Vim Text Editor, Ubuntu, MacOS
The most amazing...
...platform I've developed is Adaptly, a social media ad platform that grew to $60 million in revenue and has 100 employees.
Work Experience
CTO | Co-founder
Ikasi
- Architected and built a data science platform that allowed the easy deployment of machine learning models and could be integrated with dashboards. Worked with a product manager, a designer, and two developers to accomplish this.
- Developed a platform using Docker, Django, and PostgreSQL on the back end. The front end consisted of React and TypeScript.
- Set up a Kubernetes infrastructure on AWS using Terraform, Jenkins, RDS, kOps, and EFS.
- Led weekly sprint planning meetings with all the tasks stored in Asana.
- Managed two developers, conducted regular one-on-ones, and performed code reviews.
- Built a rewards app for casinos and retail companies in React Native.
- Fine-tuned an LLM to be used as a chatbot to help users run marketing campaigns without the need for Ikasi's team to oversee their actions.
Full-stack Developer
Crabel Capital Management
- Developed a React app that allowed the internal team to queue multiple changes to manage financial accounts for different dates. Wrote stored procedures in SQL server so that the front end could fetch data using the company's custom back-end service.
- Set up event monitoring for Node.js applications using LogicMonitor. A groovy script was created for the LogicMonitor that would hit internal APIs to get status information and then store that information and create alarms.
- Maintained multiple React and Vue.js projects, including updating libraries, upgrading interactions with back-end services, and adding new features.
Vice President of Engineering
Adaptly
- Engaged as the first developer at Adaptly, an early-stage startup, when the company consisted of five employees. Promoted to team lead and then VP of engineering as the company grew.
- Architected and helped build out the Adaptly product while working with the product and key stakeholders. Adaptly grew to over 100 employees and $60 million in revenue during this time.
- Scaled PostgreSQL to be able to handle a high workload that had initially started crashing the original single server.
- Developed a platform that quickly responded to changes in the Facebook Ads API through which the platform allowed clients to deploy their ads.
- Managed a team of 12 developers, conducted one-on-ones, and oversaw the hiring process.
Senior Developer
Thrillist
- Collaborated with a team of eight on a redesign of the website and WordPress upgrade.
- Developed and customized WordPress plugins needed for the new website.
- Tracked bugs and features using Jira while working in sprints.
Developer
Densebrain
- Developed the iOS applications and back-ends in PHP for a mobile consulting company.
- Created a system on Android and PHP that allowed delivery drivers to update the statuses of packages.
- Built NYCMate, an application that provided subway maps of New York City and the ability to find subways needed to reach your destination; this was before Google Maps had this functionality.
Experience
NFT Trading Bot
Smart Contract
• A proxy contract has been created to allow for easy upgradeability.
• Role-based authentication is used so multiple accounts can interact with the contract
• Sends and receives ERC20 and ERC 721 tokens
• Interacts with contracts from NFT marketplaces to buy and sell NFS
• Deployed using Hardhat
Custom Harmony Node
• The bot searches for opportunities on the Harmony blockchain.
• The Harmony blockchain was forked, along with go-libp2p, which is used for networking. Heavy modifications were made so that the bot could listen to transactions in the mempool and submit the buy transactions in the same block.
• The custom node is deployed to multiple servers worldwide to reduce latency.
Searcher and Prediction
• The custom Harmony node uses precomputed price predictions based on different traits of NFTs.
• A Python application pulls data directly from the blockchain and the graph APIs, floor prices are computed, as well as a predictive model. These prices are then stored in Redis, which the custom node can access.
Ikasi
http://www.ikasi.aiI developed the back end with Django and PostgreSQL, and the front end was built with React and TypeScript. Currently, it is running on Kubernetes on AWS and GCP.
Adaptly
I was the first software developer at the company and later became the VP of engineering as the company grew to millions in revenue and over 100 employees. I architected the entire platform, developed it, managed the engineering team, and worked with product to bring requested features to life.
Arbitrage Bot
The smart contract code to perform the arbitrage was written in assembly to reduce gas costs.
The bot was deployed on Ethereum, and a modified Geth node was used to allow the bot to listen for transactions in the mempool and submit arbitrage transactions in the same block.
Web3 Escrow Site
Orica V2 Token
• It had a configurable percentage that was taken from all token transfers and rewarded to all token holders. This was implemented using reflection, as implementing this with a loop would be unfeasible because of gas constraints.
• It had a configurable percentage that was taken from all token transfers and deposited into a Uniswap type liquidity pool.
• It allowed for addresses to be blacklisted, ownership to be transferred, and tokens to be burned.
• The project was set up using Hardhat. Extensive tests were written and the Uniswap features were tested using a mainnet fork.
• The project was configured to be deployable to Polygon Testnet and Mainnet
Education
Bachelor's Degree in Computer Science, Computer Engineering
University of California, Davis - Davis, CA, United States
Certifications
Sample-based Learning Methods
Coursera
Fundamentals of Reinforcement Learning
Coursera
Skills
Libraries/APIs
React, Facebook API, Backbone.js, Pandas, Scikit-learn, jQuery, Node.js, Sidekiq, REST APIs, SQLAlchemy, Twilio API, Google Maps API, Pydantic, D3.js, Recharts, TensorFlow, PyTorch, Vue, Web3.js
Tools
Jenkins, Jupyter, Apache JMeter, GitHub, Jira, Git, RabbitMQ, Apache Airflow, Apache Maven, React Apollo, Webpack, BigQuery, Celery, Amazon EKS, Terraform, Chef, ChatGPT, Vim Text Editor, Slack, Asana, Trello
Languages
Python, Ruby, JavaScript, TypeScript, Go, Clojure, Scala, CSS, PHP, HTML, SQL, Solidity, Rust, GraphQL, Solidity Assembly, Java, Snowflake, Swift, CSS3
Frameworks
Ruby on Rails (RoR), Django, Angular, Bootstrap, Flask, Jest, Material UI, Express.js, Redux, ClojureScript, Serverless Framework, Next.js, React Native, Yarn, Tailwind CSS, Spark, CakePHP, Play
Paradigms
Agile, Test-driven Development (TDD), DevOps, Asynchronous Programming, ETL, Microservices, Microservices Architecture, Object-relational Mapping (ORM), B2B
Platforms
Kubernetes, iOS, Ubuntu, Docker, Amazon Web Services (AWS), Blockchain, Ethereum, Blockchain Platforms, AWS Lambda, Firebase, DigitalOcean, Azure, WordPress, Android, Google Cloud Platform (GCP), Twilio, Vercel, MacOS, Visual Studio Code (VS Code)
Storage
PostgreSQL, MySQL, MongoDB, Redis, DB, NoSQL, Datadog, Amazon S3 (AWS S3), Google Cloud, Data Pipelines, JSON, Elasticsearch, Neo4j
Industry Expertise
Project Management
Other
Back-end, Leadership, Team Leadership, Crypto, Bitcoin, Smart Contracts, Non-fungible Tokens (NFT), Cryptocurrency, Ethereum Smart Contracts, APIs, Architecture, Technical Leadership, Tornado, CI/CD Pipelines, Back-end Development, Web Development, Single-page Applications (SPA), Full-stack, Product Management, Decentralized Finance (DeFi), Web Scraping, Data Warehousing, Software Architecture, Digital Payments, Arbitrage, Blockchain & Cryptocurrency, Web 3.0, Mobile Advertising, Decentralized Systems, Ads, Advertising Technology (Adtech), API Integration, Data Analysis, Distributed Systems, Analytical Dashboards, Data Scraping, CTO, FastAPI, Artificial Intelligence (AI), Google BigQuery, Enterprise SaaS, User Experience (UX), OpenAI GPT-3 API, OpenAI GPT-4 API, Chatbots, WebSockets, Scalability, Performance, Amazon RDS, Generative Pre-trained Transformers (GPT), Data Science, Machine Learning, Fintech, Ethers.js, Real-time Bidding (RTB), Business to Government (B2G), Web3, Cosmos
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