Stepan Maslennikov — Senior Front-End Developer, Team Lead

Stepan Maslennikov

Senior Front-End Developer · Team Lead

Front-end developer for 17 years, team lead since 2020. At Fasttrack I lead the front end of a SaaS platform for customer communication — chatbot builder, chat center, mobile app. I work mostly with React, TypeScript, MobX and RxJS and care about real-time UIs and architecture that lasts.

Core skills

TypeScript, JavaScript

React, React Native (Expo)

Angular

MobX, Redux, RxJS

Real-time UIs: WebSocket, Centrifugo

Visual editors: React Flow, dnd-kit

Data visualization: WebGL2, Canvas, ECharts

DI (InversifyJS), SOLID, design patterns

HTML, CSS, SCSS, responsive layout

Front-end ecosystem

Mantine, Mantine DataTable, styled-components, CSS Modules

Forms: Mantine Form, Formik, Zod, Yup

React Router, i18next, TinyMCE, CodeMirror

React Native: Expo, React Navigation, Reanimated

Vite, Webpack, Babel

Jest, Vitest, Testing Library, Storybook

ESLint, Prettier, Stylelint, Sentry

Work experience

Front-End Team Lead · Fasttrack

February 2020 — present · Remote, Moscow-based company

Fasttrack is a SaaS platform for automating online communication: chatbots, an omnichannel chat center for operators, mailings and CRM integrations.

Lead front-end development of the core product — chatbot builder, chat center, campaign and funnel editors, analytics: a 410k-line codebase, 96% TypeScript, with 8,000+ of my commits since 2020.
Built the chat-center mobile app in React Native (Expo) from the first commit to a team beta in three months, reusing the web chat center's logic through a platform-independent TypeScript core.
Wrote 260 of the product's 339 front-end test files (Jest), making tests a routine part of feature work.
Own the client architecture: MobX, RxJS and dependency injection (InversifyJS), real-time updates over Centrifugo WebSockets, and the module-by-module migration from Bootstrap to Mantine.
Developed embeddable products: the website chat widget, on-site forms (about 90% of the commits), VK Mini Apps and an amoCRM widget.
Lead a team of four front-end developers: planning and estimates with the PM, code review, onboarding. Mentored a junior developer in JavaScript and React.

Senior Front-End Developer · Deligo

November 2018 — February 2020 · Moscow, Russia

Developed and maintained web applications with React and Angular, from requirements to production.

Worked with product, design and back-end teams on requirements, UI/UX decisions and API contracts.
Reviewed code, mentored junior developers and helped shape the front-end architecture.

Front-End Developer · Yzer

April 2016 — November 2018 · Dubai, UAE

Built web applications with React and Backbone.js.

Turned design mockups into responsive, cross-browser interfaces and integrated REST APIs with the back-end team.
Took part in code review, task planning and estimates.

Earlier experience

Front-End Developer · Alta-Soft

2014 — 2016 · Moscow, Russia

Web interfaces for customs software and an online portal for foreign trade.

Junior Front-End Developer · Ticno

2011 — 2013 · Petrozavodsk, Russia

Responsive layouts and interactive pages with JavaScript and jQuery.

Freelance Web Developer · fl.ru

2009 — 2011

Websites and web interfaces for small businesses, from requirements to launch.