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Hi, I’m Krisztián Szalai, a Senior Frontend Developer. I ship robust web and mobile interfaces for startups, scale-ups, and enterprise teams. I specialize in real-time, multi-tenant, security-sensitive systems using Next.js, React Native, and TypeScript. I enjoy mentoring juniors, shaping architecture, and turning complex requirements into delightful, accessible products.…

Krisztián Szalai

Full Stack Developer, Web Developer, Front-End Developer, +2

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Hi, I’m Krisztián Szalai, a Senior Frontend Developer. I ship robust web and mobile interfaces for startups, scale-ups, and enterprise teams. I specialize in real-time, multi-tenant, security-sensitive systems using Next.js, React Native, and TypeScript. I enjoy mentoring juniors, shaping architecture, and turning complex requirements into delightful, accessible products.…

Available to hire

Hi, I’m Krisztián Szalai, a Senior Frontend Developer. I ship robust web and mobile interfaces for startups, scale-ups, and enterprise teams.

I specialize in real-time, multi-tenant, security-sensitive systems using Next.js, React Native, and TypeScript. I enjoy mentoring juniors, shaping architecture, and turning complex requirements into delightful, accessible products.

Skills

Experience Level

Expert

Expert

Expert

Expert

Language

Hungarian

Fluent

English

Advanced

Japanese

Beginner

Work Experience

Senior Frontend Developer at Morris on Street Advisors

May 2, 2025 - Present

Led the development of a Next.js frontend for a multi-tenant industrial monitoring platform; mentored a junior frontend developer; collaborated with a Ruby on Rails backend; implemented authentication and secure communications; led architecture decisions for a reusable UI system and tenant isolation; delivered a fully offline-capable PWA with push notifications and Jest/Playwright test coverage.

Senior Frontend Developer at StellarUp

September 1, 2024 - May 1, 2025

Contractor alongside the core dev team on Fiona (social/lifestyle platform for creators and brands); built MVP cross-platform mobile app with React Native and Expo; aligned with Next.js web experiences; integrated Vendure e-commerce storefront; Zoho SalesIQ for live support; synchronized live feeds across web and mobile; contributed to architecture decisions for a reusable UI system.

Full Stack Developer at Gridlock Inc.

January 1, 2023 - February 1, 2024

Remote startup; self-custodial crypto wallet for iOS and Android — backup, recovery, and exchange-related flows where trust and reliability matter; React Native app with Node.js/Express and MongoDB; contributed a Rust module for a security-sensitive piece; owned App Store and Play Store releases; raised quality via Sentry; performance improvements.

Full Stack Developer at Viddl

May 1, 2021 - December 1, 2022

Budapest startup; shipped features across last-mile logistics and the HSUP e-learning product (thousands of students each semester); delivery platform: map-based tracking, route guidance, real-time updates — shared logic across web, mobile, and ops in an Nx monorepo (React, React Native, Expo, Node.js, Express); HSUP: student and admin surfaces with NestJS, Strapi CMS, and MongoDB; exam workflow at scale.

Frontend Engineer at Budapest-based International software and integration provider

September 1, 2018 - May 1, 2021

Worked in the custom development group (~10 engineers) on client-specific products; enterprise healthcare communications platform for secure information exchange; migrated legacy JavaScript to Angular; contributed to a WebRTC-based enterprise conferencing system; Technologies: Angular, TypeScript, Express.js, WebRTC.