Senior Node.js Developer

Senior • Hybrid

Warsaw, Poland

Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promote a diverse and inclusive work environment.

Join an international team working for a client in the financial sector as a Node.js Developer. This is a senior-level backend development role focused on building and maintaining robust APIs and server-side logic. You’ll collaborate with experienced engineers and contribute to a well-documented, scalable architecture. The work is mostly remote, but you will attend monthly, two/to three-day meetings in Warsaw.

Your tasks

Developing and maintaining API endpoints and server-side logic within SvelteKit’s server.js files and form actions
Ensuring proper error handling and validation across server-side operations
Building database integration layers using PostgreSQL clients
Writing SQL queries for CRUD operations and implementing data models aligned with frontend needs
Creating unit tests for server-side functions and API routes
Participating in code reviews and following established patterns for authentication, authorization, and data fetching
Debugging issues across the full stack
Contributing to the documentation of API specifications and database schemas

Requirements

Minimum 5 years of experience with Node.js
Strong understanding of backend architecture and API design
Experience with PostgreSQL and writing efficient SQL queries
Familiarity with unit testing and code review practices
Fluent English (spoken and written)
Ability to work effectively in an international team
Residing in Poland required
Fluent Polish required

Nice-to-have requirements

Experience with Svelte

What we offer

Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas
Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market
We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022
Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more
Comfortable workplace – class A offices or remote work
Dozens of fascinating projects for prestigious brands from all over the world
PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers
Investment in your growth – meetups, webinars, training platform and technology blog – you choose
Fantastic atmosphere created by all Sii Power People

Join the Sii team – develop your skills, gain experience, and build your career!

Sii

Sii is a company recognized as a "Great Place to Work" since 2015, thanks to employee feedback and the implementation of new ideas. Established in 2006, Sii has demonstrated financial stability with a revenue of 2.1 billion PLN and no debts. The company shares its profits with employees, having allocated over 76 million PLN for this purpose since 2022. Sii offers a rich benefits package, including private healthcare, a cafeteria platform, and discounts on cars. Employees can work in comfortable A-class offices or remotely. Sii is involved in numerous fascinating projects for prestigious global brands and invests 1 million PLN annually to support employee passions and volunteer actions. The company emphasizes personal development through meetups, webinars, a training platform, and a technology blog. Sii is characterized by a fantastic atmosphere created by its "Sii Power People."