I am developing microservices in an international B2B payment platform using the tech stack: Java 17, Spring Boot, Spring Data JPA, PostgreSQL, Redis, gRPC, Kafka.

The most I can tell because of a strict NDA:In terms of the frontend, I implemented tasks with a level of complexity and tech stack similar to my previous place of work.But for the most part (70% of tasks), I was developing microservices for the backend on Java 17, using the tech stack: Spring Boot, MyBatis, PostgreSQL, Redis, Thrift, Kafka.

Developed and had full responsibility for 2 really difficult single page applications using TypeScript and React for a Swiss international fintech project: B2C app and admin dashboard.Implemented personally:- Difficult multi-step flows for user KYC and asset transactions (bank cards deposits and withdrawals, fiat/crypto exchanges, crypto withdrawals to external wallets).- MVVM architecture with clear separation into layers, based on OOP approaches, data binding via MobX and Dependency injection via InversifyJS.- A set of measures to ensure the security of a web application based on OWASP Top 10.- A set of measures to optimize and speed up the web application: code-splitting, gzip, caching and compression of statics, prioritize/lazy loading, media queries, virtual rendering of large collections and pagination, simplification of CSS selectors.- Implementation of codebase quality control tools: prettier, stylelint, eslint, sonarjs, lint-staged, husky, testing-library, jest, TypeDoc.- Writing Dockerfiles for deployment to multiple environments and other SRE assistance.- Multilingual i18n support in 4 languages ​​without reloading the page.- Dark theme using prefers-color-scheme and css-variables.- A lightweight single page application using Preact for checking bank cards, which could work as a standalone web application and as an embedded widget via Iframe with detailed development of adaptive layout: widescreen monitors, desktop screens, small 13' laptops, portrait and landscape orientations for tablets and mobile phones.

Developed and had full responsibility for 2 difficult single page applications using TypeScript and React for a chat bot constructor: B2B app and an embedded widget.Implemented personally:- An embedded widget via Iframe using TypeScript, Preact, Redux, which had very complex processing of dozens of different WebSocket events per second using RxJS.- Complex UI for a chat bot constructor using HTML5/CSS3/TypeScript.- Backend of a notification mailing service using TypeScript, Node.js, RabbitMQ, MongoDB, node-schedule.- UDF architecture of a unidirectional data flow using Redux.

Developing single page application frontends using Angular.js/Angular2/React.Developing browser extensions.Also developing backends of medium complexity using Node.js and inversify-express-utils.Gained extensive experience in developing web applications on modern frontend frameworks, learned the principles of backend operation, as well as designing REST API and tables in the database. Understanding what happens from pressing the submit button to a transaction in the database and the server response was very helpful in future projects. I mainly wrote in TypeScript.

Developed websites for large corporate clients using native web technologies: HTML5, CSS3, JS. Gained extensive experience working with vanilla JS and web API, as well as adaptive and cross-browser layout.