Web Front-End Software Engineer (For independent contractors)

About The Role Booking.com is seeking a hands-on Web Front-End Software Engineer for the Pay-in Flexibility team. This team resides within the Fintech business unit and focuses on the development, operation, and scaling of payment solutions that offer travelers diverse payment methods and flexible timing, such as "Buy Now, Pay Later" and payment capabilities such as "Pay In Your Own Currency" (PIYOC).

A Web Front-End Software Engineer on the team will design and implement scalable, highly available front-end services and components that enable travelers to choose when and in which currency to pay, while delivering clear, localized pricing information and safeguarding revenue and compliance. A suitable candidate leads the end-to-end delivery: shaping engineering requirements together with Product Managers and UX designers, making architectural trade-offs, driving experiments, and improving reliability and observability of front-end systems.

Key Responsibilities

• Design, develop, and maintain the Traveller Payments BFF (Backend-for-Frontend) — a TypeScript/Node.js GraphQL Federation service that integrates with FX Service and FX Content Service to deliver currency conversion, PIYOC eligibility, margin fee transparency, and localized price notes to the booking funnel.
• Build and evolve GraphQL resolvers and data source integrations that consume REST APIs from fx-service (exchange rates, eligibility, tokens) and fx-content-service (translated price notes, FX payment metadata).
• Develop and maintain OpenAPI and GraphQL codegen pipelines to ensure type-safe service-to-service communication and reduce manual boilerplate.
• Drive experiment-driven development using Booking’s experimentation platform (ET), enabling A/B testing of payment UX variations and PIYOC flows.
• Collaborate with back-end engineers to define and evolve API contracts (REST/GraphQL) between web front-end and upstream Java services.
• Contribute to the Node.js FX Rates client library used across Booking’s frontend ecosystem for fetching exchange rates with caching.
• Tech Stack
• Language & Runtime: TypeScript, Node.js
• Server Framework: Fastify 5, Apollo Server 5
• Build & Monorepo: Nx, pnpm, esbuild, SWC
• Validation: Zod 4
• Testing: Jest 30, ts-jest
• CI/CD: GitLab CI/CD, Harness, Kuhub
• Experimentation: Booking Experiment Tracking (ET)
• Internationalization: LingoJS (i18n/l10n framework)

Required Qualifications

• 5+ years of professional experience in front-end or full-stack software engineering.
• Strong proficiency in TypeScript and Node.js with production experience building BFF or API gateway services.
• Solid understanding of REST API design, OpenAPI specifications, and type-safe client generation.
• Experience with modern build tooling (esbuild, SWC, Nx or similar monorepo tools).
• Proficiency with testing frameworks (Jest or equivalent) including unit, integration, and contract testing.
• Ability to independently resolve production incidents and conduct root-cause analysis.
• Strong code review practices and ability to mentor less experienced engineers.

Soft Skills Front-end leadership is a primary soft skill requirement, as the role demands the ability to shape engineering requirements. Successful candidates demonstrate high levels of technical autonomy, navigate complex bottlenecks, and resolve production issues independently. Beyond individual contribution, the position requires a collaborative mindset, particularly in leading code reviews and participating in UX design sessions.

Experience This job requires 5+ years of relevant professional experience in front-end or full-stack software engineering, with demonstrable experience in TypeScript/Node.js service development and GraphQL architectures.