T

Toss

Fintech super-app for payments and banking

Frontend Developer

Frontend EngineeringConfirmed live in the last 24 hours
Full-timeSeoul, South KoreaNo salary listedIn-person

About the Job

Requirements

  • Experience operating web-based services.
  • Interest in investing and enthusiasm for development and continued growth.
  • Commitment to predictable code and consideration of flexible architecture.
  • Experience considering and optimizing browser rendering performance is desired in the role's problem-solving context.
  • Interest in designing service structures for fast and safe deployment.
  • Interest in platformizing admin and back-office products to improve development efficiency.

Responsibilities

  • Build mobile products running in Android and iOS webviews, desktop products in PC browsers, and operational back-office products using modern web technologies.
  • Create services that provide accessible investment experiences for complex investment products.
  • Use engineering techniques to deliver and support uninterrupted real-time data display and trading.
  • Build component-based interfaces with React and Next.js, using TypeScript for static type checking.
  • Manage server and client state using React Query, Recoil, and Jotai as appropriate.
  • Style mobile products with Emotion and desktop products with Vanilla Extract.
  • Use the Toss Design System to build products and contribute through bug reports and component development.
  • Process real-time data efficiently using WebSockets and server-sent events, optimizing server requests.
  • Use Yarn Berry and pnpm as package managers.
  • Use Webpack, SWC, and Babel to support fast builds and deployments.
  • Manage source code and code reviews with GitHub and GitHub Actions, including automated reviewer assignment, static analysis, and testing reports.
  • Work on data visualization such as charts, graphs, and tables, including performance optimization for visualized real-time data.
  • Handle real-time market-price traffic of up to 1,400 transactions per second through sockets.
  • Develop a design system dedicated to securities products.
  • Share technical topics, development practices, lessons learned, and knowledge with team members and frontend chapters across affiliated companies.

Desired Qualifications

  • Experience optimizing browser rendering performance.
  • Experience defining and technically solving problems proactively, implementing complex services or demanding requirements, and simplifying complex or repetitive problems through abstraction.

About the Company

Toss

Fintech super-app for payments and banking

Toss is a South Korean financial services platform that started as a peer-to-peer money transfer service and has grown into a digital 'super app' for personal finance. Its products are accessed through one mobile interface that unifies bank accounts, credit cards, loans, investments, and other financial services, including its own Toss Bank and Toss Securities. It differentiates itself by offering a broad, integrated ecosystem—combining digital banking, asset management, and brokerage services under one roof and running its own banking and securities units. Its goal is to become the leading consumer finance platform in South Korea while expanding its user base globally.

Company size
1,001-5,000
Company stage
Series G
Total funding
$1.5B
Headquarters
Seoul, South Korea
Founded
2011

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