Senior Backend Engineer (Node.js)

We are CKSource, the company behind CKEditor, a modern JavaScript/TypeScript rich text editor used by millions worldwide. We produce software components for developers, including WYSIWYG editors, file managers, and document converters. CKSource is part of Tiugo Technologies, a launchpad for developer platforms focused on content creation and digital collaboration, with brands like CKEditor, TinyMCE, ButterCMS, and Uploadcare.

• Over 5 years of software development experience.
• Strong proficiency in TypeScript and Node.js.
• Experience building and maintaining backend services: REST APIs, PostgreSQL, message queues, Docker.
• Fluency in Polish (minimum C1) and good command of English (minimum B2).
• Excellent problem-solving and communication skills.

Nice to have:

• Hands-on experience integrating LLM APIs (OpenAI, Anthropic, Google, or similar).
• Understanding of prompt engineering, function/tool calling, and streaming.
• Experience with event-driven architectures (SQS/SNS or similar).
• Familiarity with observability tools (OpenTelemetry, tracing).
• Experience with real-time data processing (streaming, WebSockets, or similar).

• Design, build, and maintain backend services that power AI features for CKEditor 5, including API orchestration, streaming, event-driven processing, and data persistence.
• Integrate and orchestrate LLM providers (OpenAI, Anthropic, Google Gemini) to deliver intelligent editing features such as contextual text suggestions and automated content generation.
• Engage in code reviews, pair programming, and cross-functional collaboration.
• Write clean, maintainable, and well-structured code with appropriate documentation.
• Share best practices on programming standards, tools, and processes to foster continuous improvement.