Golang Developer (f/m/x)

We are looking for a Senior Golang Developer to join Sii and work on a large-scale backend system delivered in cooperation with a global organization operating in the US telecommunications market. The project focuses on building and evolving a critical platform that manages registration, verification, and the lifecycle of toll-free numbers used in SMS/MMS campaigns by business customers.

You will contribute to a mature, event-driven system with strong domain logic, multiple external integrations, and real business impact. At Sii, we value long-term cooperation, stability, and continuous growth, offering access to mentoring, knowledge sharing, and further development opportunities across multiple projects.

Apply now and let us match you with this or other suitable projects at Sii!

Your tasks

• Design, develop, and maintain backend services and REST APIs supporting customer-facing and administrative systems

• Implement and evolve domain and service layers handling registration workflows, reviews, and lifecycle management

• Integrate with external systems using synchronous APIs and asynchronous event processing

• Work with PostgreSQL databases, including schema migrations and performance-oriented queries

• Contribute to system reliability, scalability, and code quality in a distributed, event-driven architecture

Requirements

• At least 5 years of professional experience as a backend or software developer, including Golang

• Strong knowledge of building HTTP APIs and backend services in distributed systems

• Experience with relational databases, particularly PostgreSQL, and data migrations

• Familiarity with event-driven architectures and asynchronous processing (e.g., Kafka)

• English proficiency at B2 level or higher, enabling effective communication in an international environment

• Residing in Poland required

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 

If you want to work on systems with high operational significance — apply now!