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I'm Shay Tessler, a Senior Software Engineer with hands-on experience designing and delivering high-performance, scalable applications across backend and frontend. I lead development teams with a human-centered approach and take products from concept to production. My expertise spans Python, Node.js, React, AWS, Docker, and microservices, with a focus on reliable, maintainable, and high-quality software solutions. I'm passionate about building teams, mentoring engineers, and delivering impact-driven features that improve workflows and user experience.…I'm Shay Tessler, a Senior Software Engineer with hands-on experience designing and delivering high-performance, scalable applications across backend and frontend. I lead development teams with a human-centered approach and take products from concept to production. My expertise spans Python, Node.js, React, AWS, Docker, and microservices, with a focus on reliable, maintainable, and high-quality software solutions. I'm passionate about building teams, mentoring engineers, and delivering impact-driven features that improve workflows and user experience.

Shay Tessler

Full Stack Developer, Web Developer, Back-End Developer, +3

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I'm Shay Tessler, a Senior Software Engineer with hands-on experience designing and delivering high-performance, scalable applications across backend and frontend. I lead development teams with a human-centered approach and take products from concept to production. My expertise spans Python, Node.js, React, AWS, Docker, and microservices, with a focus on reliable, maintainable, and high-quality software solutions. I'm passionate about building teams, mentoring engineers, and delivering impact-driven features that improve workflows and user experience.…I'm Shay Tessler, a Senior Software Engineer with hands-on experience designing and delivering high-performance, scalable applications across backend and frontend. I lead development teams with a human-centered approach and take products from concept to production. My expertise spans Python, Node.js, React, AWS, Docker, and microservices, with a focus on reliable, maintainable, and high-quality software solutions. I'm passionate about building teams, mentoring engineers, and delivering impact-driven features that improve workflows and user experience.

Available to hire

I’m Shay Tessler, a Senior Software Engineer with hands-on experience designing and delivering high-performance, scalable applications across backend and frontend. I lead development teams with a human-centered approach and take products from concept to production. My expertise spans Python, Node.js, React, AWS, Docker, and microservices, with a focus on reliable, maintainable, and high-quality software solutions.

I’m passionate about building teams, mentoring engineers, and delivering impact-driven features that improve workflows and user experience.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Lead Full Stack Developer at Una

December 31, 2025 - October 7, 2025

Led the design and development of a multi-service Python-based architecture, contributing to core platform features and overall system robustness. Delivered frontend and backend enhancements with a focus on reliability and scalability. Technologies included React Native, SOLR, Neo4J, WebSocket, RabbitMQ, and Memcached.

Lead Full Stack Developer at Una

January 1, 2025 - January 1, 2025

Architected and led development of Una, a multi-service system built in Python, contributing to core platform features.

Lead Full Stack Developer at Una

January 1, 2025 - October 7, 2025

Designed and developed a multi-service system architecture in Python, contributing to core platform features.

Senior Full Stack Developer at Fiverr Business (Freelance)

December 31, 2023 - October 7, 2025

Designed and delivered new product features with emphasis on stability and performance; refactored a critical microservice to boost reliability; integrated external systems (Zendesk, Monday) to streamline workflows; improved data flow across systems and contributed to hackathon prototypes that influenced product direction.

Senior Full Stack Developer (Contract) at Fiverr Business

January 1, 2023 - January 1, 2023

Designed and delivered new product features, ensured stability and performance; refactored a critical microservice boosting reliability; integrated external systems (Zendesk, Monday); improved data flow across systems; contributed to company hackathons.

Senior Full Stack Developer at Fiverr Business (Freelance)

January 1, 2023 - October 7, 2025

Designed and delivered new product features, ensured stability and smooth performance; refactored a critical microservice to boost reliability and reduce maintenance; integrated external systems (Zendesk, Monday); improved data flow across systems for accuracy and efficiency; contributed to hackathons shaping future product features.

Lead Full Stack Developer at Yedda (Freelance)

December 31, 2021 - October 7, 2025

Maintained and stabilized a custom AI engine, boosting company output by 35%; built and led a development team; implemented agile processes, code reviews, and daily Scrum meetings.

Lead Full Stack Developer at Yedda

January 1, 2021 - January 1, 2021

Maintained and stabilized a custom AI engine; hired and built a team of developers; implemented and trained for Agile, code review, and daily Scrum meetings.

Lead Full Stack Developer at Yedda (Freelance)

January 1, 2021 - October 7, 2025

Maintained and stabilized a custom AI engine, boosting company output by 35%; hired and built a team of developers; implemented and trained for agile, code review, and daily Scrum meetings.

Senior Full Stack Developer at FDNA (Freelance)

December 31, 2020 - October 7, 2025

Designed and built the backend of the genome ordering platform from scratch; developed the frontend in Next.js for a modern and responsive user experience; technologies included Redux, ES6, and Jenkins for CI.

Lead Full Stack Developer at University of Bonn (Freelance)

December 31, 2020 - October 7, 2025

Architected a Next-Generation Sequencing (NGS) system on Linux; designed and developed a clinician ordering platform; led the integration effort between the Universities of Bonn and Cologne; implemented agile workflows and code review practices.

Senior Full Stack Developer at FDNA

January 1, 2020 - January 1, 2020

Designed and built the backend of the genome ordering platform from scratch, ensuring scalability and seamless integration with the frontend; developed the platform's frontend in Next.js for a modern and responsive user experience; Technologies: Redux, ES6, Jenkins.

Lead Full Stack Developer at University of Bonn

January 1, 2020 - January 1, 2020

Architected a Next-Generation Sequencing (NGS) system on Linux; designed and developed a clinician ordering platform from scratch; led the integration effort between the Universities of Bonn and Cologne; implemented and trained for Agile, code review, and daily Scrum meetings.

Senior Full Stack Developer at FDNA (Freelance)

January 1, 2020 - October 7, 2025

Lead Full Stack Developer at University of Bonn (Freelance)

January 1, 2020 - October 7, 2025

Senior Full Stack Developer at OwnBackup (Employee)

December 31, 2019 - October 7, 2025

Developed, maintained, and led new features; instructed and trained the team on Docker; technologies included MongoDB, Sentry, Vagrant, Linux, and jQuery.

Senior Full Stack Developer at OwnBackup

January 1, 2019 - January 1, 2019

Developed, maintained, and led new features for the company's product; instructed and trained the team on Docker.

Senior Full Stack Developer at OwnBackup (Employee)

January 1, 2019 - October 7, 2025

Developed, maintained, and led new features for the company's product; instructed and trained the team on Docker.

Lead Full Stack Developer at FDNA (Employee)

December 31, 2018 - October 7, 2025

Led developers and drove feature development; directed a smooth transition from Angular.js to React; boosted product performance by 30% in a high-traffic application; technologies included Redux, Angular.js, ES5, Gulp, Gradle, PHP, Laravel, Linux, Java, JUnit, Multithreading, and Jenkins.

Lead Full Stack Developer at FDNA

January 1, 2018 - January 1, 2018

Led developers and drove feature development; transitioned from Angular.js to React; boosted product performance by 30%; supported a high-traffic application handling hundreds of requests/sec; Technologies: Redux, Angular.js, ES5, Gulp, Gradle, PHP, Laravel, Linux, Java, JUnit, Multithreading, Jenkins.

Lead Full Stack Developer at FDNA (Employee)

January 1, 2018 - October 7, 2025

Led developers and drove feature development; directed a smooth transition from Angular.js to React; boosted product performance by 30%; supported a high-traffic application handling hundreds of requests/sec.

Front End Developer at Enabley (formerly TimeToKnow) (Employee)

December 31, 2015 - October 7, 2025

Developed and maintained the legacy product; transitioned to the new product development team; contributed to key features and system improvements for the new product.

Front End Developer at Enabley (TimeToKnow)

January 1, 2015 - January 1, 2015

Developed and maintained the company's legacy product; transitioned to the new product development team; Advanced to the senior development team, contributing to key features and system improvements for the company's new product.

Front End Developer at Enabley (formerly TimeToKnow) (Employee)

January 1, 2015 - October 7, 2025

Developed and maintained the company's legacy product; transitioned to the new product development team; advanced to the senior development team, contributing to key features and system improvements for the company's new product.

Senior Full Stack Developer at Buzzilla (Employee)

December 31, 2013 - October 7, 2025

Built the company's product from scratch; collaborated with internal research teams to improve the product; technologies included Play Framework, JPA/Hibernate, and jQuery.

Senior Full Stack Developer at Buzzilla

January 1, 2013 - January 1, 2013

Built the company's product from scratch; collaborated with internal research teams to improve the product.

Senior Full Stack Developer at Buzzilla (Employee)

January 1, 2013 - October 7, 2025

Built the company's product from scratch; collaborated with internal research teams to improve the product.

Team Leader, Java Developer at 10Levels (Employee)

December 31, 2010 - October 7, 2025

Built an automation tool and the OMS Operations Management System from scratch; managed a team of developers and led multiple project missions; handled post-sale client relations and tailored solutions.

Team Leader, Java Developer at 10Levels

January 1, 2010 - January 1, 2010

Built an automation tool and the OMS Operations Management System from scratch; Managed a team of developers and led multiple project missions; Managed post-sale client relations.

Team Leader, Java Developer at 10Levels (Employee)

January 1, 2010 - October 7, 2025

Built an automation tool and the OMS Operations Management System from scratch; managed a team of developers and led multiple project missions; managed post-sale client relations: visited clients, gathered requirements, and developed tailored solutions.