Marcell T.

About Me

Marcell is a full-stack developer with several years of experience developing various projects from CLI tools to enterprise web applications. In the last few years, Marcell has been focusing on front-end development with React and TypeScript while also engaging in leadership duties. In his free time, Marcell keeps up to date on the latest technologies and architectural patterns so that he can construct the best solution that meets his client's needs—both in terms of UX and code quality.

Frontend

CSS React

Backend

QA & Testing

Workflow

Other

Work history

Stoplight, Inc.
Senior Software Engineer | Team Lead
2020 - Present (5 years)
Remote
  • Collaborated closely with the product team to ensure the success of Stoplight Elements, our new open-source initiative.

  • Facilitated Scrum ceremonies and led technical discussions while also working as an individual contributor—ensuring the project's quality and timely delivery.

  • Built an open-source library that powered the API documentation portals of big enterprises and small companies alike.

JavaScriptTypescriptReact MobXGitOpenAPI Node.jsJestWebpackWeb ComponentsAgile software developmentREST APIs GraphqlPostgreSQLCSSSQLDatabasesPerformance Scaling Front-end User Interface (UI) GithubUI ComponentsFront-end Development Team Leadership Technical Leadership Software ArchitectureArchitecture SaaSAPIsHTMLJSX
Appsint Ltd.
Senior Full-stack Engineer | Team Lead
2018 - 2020 (2 years)
Remote
  • Led the transition from a legacy ASP.NET Web Forms UI to React to enable new features.

  • Mentored junior developers, facilitated sprint planning, reviewed code, and so on.

  • Advised management in technology-related decisions.

ASP.NET CoreC#JavaScriptTypescriptReact ReduxWebpackSQLMicrosoft SQL Server MySQLGitCSSDatabasesREST APIs WebSockets Performance Scaling Front-end User Interface (UI) GithubUI ComponentsFront-end Development Team Leadership Technical Leadership Software ArchitectureArchitecture SaaS.NET CoreAPIsHTMLJSX
Appsint
Full-stack Engineer
2017 - 2018 (1 year)
Remote
  • Contributed to the build of an in-house framework powering multiple enterprise systems.

  • Worked closely in an Agile environment with product owners to deliver perfect solutions that met our customers' needs.

  • Assisted multiple large enterprise customers (including banks and government entities) with their on-premise installation needs and problems.

ASP.NET MVCC#JavaScriptjQuerySQLMicrosoft SQL Server GitCSSDatabasesREST APIs WebSockets Performance Scaling Front-end User Interface (UI) GithubUI ComponentsFront-end Development Software ArchitectureArchitecture SaaS.NET CoreAPIsHTML
IT-Runner Ltd.
Software Engineer
2015 - 2016 (1 year)
Remote
  • Worked as the sole developer in an IT operations firm and handled almost every case where the customer needed a custom software tool to solve their unique problem.

  • Worked with a wide variety of programming languages and environments, ranging from VBA macros to a mass-email-delivery PHP application.

  • Serviced and supported Linux and Windows-based servers and networking hardware.

Freelance
Freelance Developer
2010 - Present (15 years)
Remote
  • Took on several freelance projects, ranging from custom websites to data-processing tools for accounting firms.

  • Published applications to the Windows and the Google Play stores, such as a study-management app used by thousands of students or another one used in advanced pilot-training.

  • Regularly mentored junior developers on an online tutoring platform, helping them advance in their careers and working with them to unblock a project should they get stuck with anything.

C#Windows Store PHPMySQLHTML5CSSJavaScriptASP.NETWindows Presentation Foundation (WPF)Windows Forms (WinForms) Bash Script React ReduxTeam Mentoring GitNode.jsTypescriptNext.jsSQLDatabasesREST APIs Front-end User Interface (UI) GithubUI ComponentsFront-end Development Software ArchitectureArchitecture SaaSJestServerless Architecture.NET CoreAPIsHTMLAmazon S3 (AWS S3) JSX NestJS

Showcase

Stoplight Elements
  • Stoplight Elements is a library that generates documentation from OpenAPI specifications.

  • The team led this project, delivering it predictably and on time while maintaining a high-quality standard.

  • The project involved complex technical challenges, including UI design, YAML parsing, REFs, and HTTP request maker UI development.

Enterprise eCommerce for Lick
  • Lick Home Ltd. is a UK startup focused on revolutionizing the home decor industry through a custom eCommerce store.

  • They are utilizing Shopify Plus for checkout, with a separate headless CMS and custom REST API.

  • The company is implementing advanced technologies like AWS lambdas, managed queues, and API gateways to scale their platform.

B2B Workflow Automation for a US eCommerce Wholesaler
  • Worked with a US personal care brand, Lovery, to automate processes related to inventory, sales, and fulfillment.

  • Reduced manual labor requirements significantly due to automation of order processing.

  • Improved processing times resulting from the automation of workflows.

Education

Education
Bachelor's Degree in Business Information Systems
Corvinus University of Budapest
2016 - 2019 (3 years)