Senior Full-Stack Engineer (TypeScript, React, Node.js)

WhyHireWrong?; Warsaw (IN); Presencial; USD 110 000 - 150 000; Tempo integral

Resumo da oferta

WhyHireWrong? is seeking a seasoned full-stack engineer to own features from idea to release in a seed-stage B2B SaaS context.

You’ll work across frontend and backend (TypeScript, React, Node.js) and collaborate closely with designers and founders to shape architecture as the product grows. You’ll turn Figma designs into clean, accessible UIs, improve APIs and developer tooling, and ensure a maintainable codebase.

Qualificações

• Fluent Polish (or strong proficiency) and residency in Poland.
• 5+ years of professional software engineering experience in SaaS or product environments.
• Strong TypeScript and Node.js production experience with customer-facing features.
• Production experience with React.
• Experience taking at least one customer-facing feature from requirements to release.
• Comfortable working from Figma designs.
• Able to work independently in an early-stage team without detailed specs.

Responsabilidades

• Build and ship full-stack features in TypeScript with React on the frontend and Node.js on the backend.
• Own features end to end from idea to release, including requirements clarification and testing.
• Develop merchant-facing subscription, billing, and checkout flows.
• Improve APIs, docs, integrations, onboarding, and error messages for developers.
• Turn Figma designs into accessible UI and suggest UX improvements.
• Keep architecture simple, observable, and maintainable; avoid over-engineering.
• Conduct code reviews, write automated tests, and maintain useful documentation.
• Leverage AI coding tools to save time or improve quality.

Conhecimentos

Polish (fluent)

TypeScript

Node.js

React

Figma

Independent work

Customer-facing features

AI coding tools

Ferramentas

Next.js

Vue

Nuxt

Fastify

Express

NestJS

Descrição da oferta de emprego

About the role

A seed-stage B2B SaaS company is building subscription infrastructure for e-commerce: billing, checkout and developer tools. They need a full-stack engineer who owns features from idea to release. You'll work across frontend and backend, talk to designers and founders directly, and help shape the architecture as the product grows.

What you will do

• Build and ship full-stack features in TypeScript, with React on the frontend and Node.js on the backend.
• Own features end to end: clarify requirements, propose an approach, build, test, release and check the impact.
• Build merchant-facing subscription, billing and checkout flows that are clear and reliable.
• Improve the developer-facing side of the product: APIs, docs, integrations, onboarding and error messages.
• Turn Figma designs into clean, accessible UI and suggest practical UX improvements.
• Keep the architecture simple, observable and maintainable. No over-engineering.
• Do code reviews, write automated tests and keep documentation useful.
• Use AI coding tools where they save time or improve quality.

Requirements

• Fluent Polish and residence in Poland.
• 5+ years of professional software engineering experience, mostly in product or SaaS companies, not only agencies or consulting.
• Strong TypeScript and Node.js in production, with features used by real customers.
• Production experience with React.
• Experience taking at least one customer-facing feature from requirements to release.
• Comfortable working from Figma designs.
• Able to work independently in an early-stage team without detailed specs.

Nice to have

• Next.js, or Vue and Nuxt.
• Fastify, Express or NestJS.
• Payments or subscriptions: recurring billing, payment providers, invoicing, proration, dunning.
• E-commerce: Shopify, WooCommerce, Magento or headless commerce.
• Public APIs, SDKs, webhooks or developer documentation.
• Startup experience, especially in teams under 200 people.
• Hands-on use of AI and LLM tools (Cursor, Copilot, Claude, OpenAI).