
Saša Šijak
Full-stack Developer
Saša has more than ten years of professional software engineering experience under his belt. He also has strong analytical skills, a wide range of computer expertise, and a history of successful project outcomes. All in all, Saša is organized, attentive-to-details, and a meticulous self-starter who's able to organize and prioritize multiple tasks and stay calm and productive under pressure.
Portfolio
Experience
Java - 9 yearsSoftware Architecture - 7 yearsFull-stack - 5 yearsSingle-page Applications (SPA) - 5 yearsJavaScript - 5 yearsSpring - 4 yearsGatsby - 3 yearsReact - 3 yearsAvailability
Preferred Environment
Slack, Jenkins, YouTrack, Jira, Git, Linux, IntelliJ
The most amazing...
...project I've done was working with a team that made a distributed search engine which was bought by Facebook.
Work Experience
Full-stack Engineer
Pwnalot LLC
- Developed a website to sell beautiful and responsive UI blocks made with ChakraUI and Framer Motion with code export to NextJS or GatsbyJS: https://reactui.boutique.
- Created a website with a purpose of a digital will. Created switches, how often should service checkup on you and if you become unavailable it sends your predefined messages. https://livemanswitch.com.
- Handed all sides of the business: registration, taxes, marketing, sales, project implementation, and more.
Freelance Full-stack Engineer
Toptal
- Implemented public-facing websites for the most popular app which connects classrooms with parents and engage kids Classdojo: https://classdojo.com, https://ideas.classdojo.com, https://blog.classdojo.com.
- Developed mobile apps for one of the largest car manufacturers.
- Implemented a website in React/Gatsby that was featured on Adidas's homepage and is a heavily marketed campaign for sports coaches to teach them how to approach and keep girls in sport (keepgirlsinsport.com).
- Worked in a team that created an engagement platform designed for education (Quadwrangle). My responsibilities were a front end in AngularJS, back-end API in Play framework, and creating Docker-based deployments.
- Implemented a web app from scratch for a small business in a timber processing domain. Previously they organized and tracked their business by using large Excel tables and files, shared through email and Dropbox.
- Built a website for a school with GatsbyJS and backed by a headless CMS Contentful (https://www.ecfs.org/en/).
Owner | Software Engineer
Geek (Sole Proprietorship)
- Created the Hocudabudem.fit website from scratch using GatsbyJS, React, GraphQL, Netlify CMS, and hosted it on Netlify; also implemented the SEO and marketing campaigns.
- Developed a multiplayer and multiplatform soccer game.
- Built a multiplayer turn-based browser game implemented using Vue.js and Firebase platform.
- Created an open-source Kotlin-based startup template.
Software Engineer
Mozzart
- Pushed for and led the implementation of a new land-based casino system that replaced a legacy one—resulting in new business opportunities and better architecture. Used in more than 700 hundred betting shops and six countries.
- Hacked a proprietary communication protocol for gambling machines on my own; after which we could make our own solution pushing out third parties, cutting on expenses, and opening the doors for exciting possibilities.
- Implemented the jackpot animation and notification system. It replaced a third-party solution and enabled us to push features much faster. This app is used in every casino and it boosted profits and improved player's experience.
- Strove continuously to improve the business and system—going beyond basic requirements and pushing the boundaries of the old enterprise system and company. Provided many proposals and solutions to more than just technical problems.
- Implemented a betting machines/terminals project where machines are placed into betting shops or cafes. It involved integrating several hardware products, make an API, deploy the system to several hundred machines, server and machine administration.
- Implemented a messaging system which allows our managers to interact with players and customers, and that also sends automated messages based on some configurable rules.
Software Engineer
QuadWrangle
- Implemented new-and-supported old features for Quadwrangle (engagement platform targeting universities).
- Developed a new deployment system using Docker.
- Integrated several different APIs.
Software Engineer | Team Lead
Alteatec
- Designed the back-end architecture for a scalable, high-performing online casino system.
- Led the team which implemented the back end from scratch. The back end was then used by various clients and tens of thousands of players making big profits.
- Implemented various gaming providers and communicated with external providers.
Software Engineer
Wowd
- Improved the app performance by profiling and optimizing a Java virtual machine.
- Created the first version of the Wowd iOS app.
- Handled QA and testing.
Associate Lecturer
Union University, School of Computing
- Organized lectures for the operating systems class.
- Implemented various operating system parts with students in a simulator—improving their understanding and knowledge.
- Earned one of the best student evaluations given during my time there.
Software Test Engineer
Asseco
- Built a custom testing tool for Asseco banking software.
- Designed and wrote various test cases.
- Organized the Asseco programming challenges in the university.
Experience
Classdojo Websites
https://classdojo.comThe website was previously built with older technology and was in a need of a complete rewrite. I've implemented the website with React, GatsbyJS, and Styled System.
Besides the main websites, I implemented other public-facing sites ideas.classdojo.com and blog.classdojo.com.
Website for Adidas
https://www.keepgirlsinsport.comAs the sole developer, I built the website using React/Gatsby along with implementing the custom styling and design.
Online Casino Management System
Technologies: Python, ZeroMQ, MySQL, SQLAlchemy, Redis, Linux
React UI Boutique
https://reactui.boutiqueBuilt hundreds of ready-to-use blocks and drag and drop builder to quickly build pages and preview them.
I built it from scratch and did everything from developing it to marketing, sales, deployments, and support.
Live Man Switch
https://livemanswitch.comIt is a digital version of a physical switch that is designed to be activated or deactivated if the human operator becomes incapacitated, such as through death, loss of consciousness or being bodily removed from control.
User can create switches, and configure how often should service check-up on them, over which channel (email or SMS) and if they become unavailable it sends their predefined messages.
ECFS School Website
https://www.ecfs.org/en/I did not build the site from scratch. I inherited the project at some point because the client was not happy with the previous agency and I am now the sole developer on this website for more than a year.
Land-based Casino Management System
Technologies: Java, Spring Framework, AngularJS, Oracle Database, Redis, Linux, ActiveMQ
Customer Messaging System
Technologies: Java, Spring, Vue.js, ActiveMQ, Oracle, Linux
Betting Machine and Terminal
Technologies: Java, Spring, Vue.js, ActiveMQ, SQLite, Oracle, Linux
Jackpot System with Roulette
Technologies: Java, Spring, ActiveMQ, Oracle, Linux
Amazing Multiplayer Soccer Game
Technologies: Java, JavaScript, Vert.x
Hacked Proprietery Protocol
Hocudabudem.fit | Online Presence
https://hocudabudem.fitTechnologies: React, GatsbyJS, Firebase, WordPress, Contentful, Netlify
Flat (Apartment) Ad Scraper
To solve this, I wrote a program that scrapes websites with flat ads every few hours, filters out all the agency and fishy ads, and showed me all good ones in the part of the city and other parameters that I was interested in.
In the end, I found a flat in one day. I used this program again two years later and had the same result—I also found a flat in one day. Then I decided to share it with friends.
Technologies: Java
Fun Factory Apps on Android
Technologies: Java, Android
Skills
Languages
Java, HTML, SQL, JavaScript, CSS, Sass, YAML, C#, HTML5, Python, TypeScript, Kotlin, GraphQL
Frameworks
Spring, Spring Boot, Spring 5, Tailwind CSS, Next.js, JPA, Play Framework, Flask, AngularJS, Bootstrap, Ktor, Redux
Libraries/APIs
React, Vue, Vuex, MobX, ZeroMQ, Stripe, Coinbase API, Twilio API, Firebase Web SDK, Socket.IO, JOOQ, SQLAlchemy, Google Cloud API, Emotion Library, Google Maps, Google Geocoding API
Tools
JetBrains, Terminal, Slack, Git, ActiveMQ, Apache Maven, IntelliJ, Facebook Pixel, Google Analytics, MailerLite, Figma, Docker Hub, Vagrant, YouTrack, Jenkins, Subversion (SVN), Gradle, PostCSS, JSX
Platforms
Netlify, Linux, Contentful, Oracle, DigitalOcean, Mailgun, Mixpanel, Algolia, Firebase, Kubernetes, Docker, Amazon EC2, Amazon Web Services (AWS)
Storage
Redis, H2, PostgreSQL, Cloud Firestore, Firebase Realtime Database, Spring Data, Microsoft SQL Server, Google Cloud, Memcached, Oracle 12c, MySQL, MongoDB, MySQL/MariaDB
Other
Single-page Applications (SPA), Full-stack, Web App Deployment, Creative Problem Solving, Software Design, Gatsby, Front-end, User Interface (UI), Casinos & Gaming, APIs, Software Architecture, Server Administration, Web Development, Browsers, Data Structures, Operating Systems, Linux Administration, Cordova, Web Analytics, Google Tag Manager, Design Systems, Chakra UI, Framer Motion, Vercel, Message Queues, Analytics, Administration, Cloud, Styled-components
Paradigms
Scrum, Design Patterns, REST, Service-oriented Architecture (SOA), Object-oriented Programming (OOP), Continuous Integration (CI), DevOps, Test-driven Development (TDD), Functional Programming, On-page SEO, Testing, Hosting
Education
Bachelor's Degree in Computer Science
Union University, School of Computing - Belgrade, Serbia