Senior Backend Developer (Node.js)

MasterBorn works with US clients from the high-end American IT market, collaborating with well-established companies and startups in early stages (MVPs) across diverse industries such as FinTech, SportsTech, and MedTech. The tech stack includes React, Node.js, and TypeScript, with teams operating within the Polish time zone.

• 4+ years of commercial experience in Node.js
• Deep knowledge of at least one Node.js backend framework (e.g., Express.js, NestJS, Fastify)
• Proficient in designing, developing, and maintaining high-performance, scalable, and secure REST APIs
• Familiarity with GraphQL
• Experience with Docker for environment preparation and debugging
• Experience with AWS services such as S3, Cognito, SNS, SQS
• Experience with SQL and NoSQL databases, using ORM or query builders (e.g., Prisma, Knex)
• Experienced with TypeScript
• Experience designing and building AI-powered applications or features using AI/LLM tools, APIs, embeddings, vector search, or prompt/context optimization
• Use AI tools in daily engineering work understanding their limitations and risks
• Ability to connect technical decisions with product and business goals
• Proactive risk identification and proposing scalable, maintainable solutions
• English language proficiency at B2/C1 level
• Polish language proficiency at C1 level
• Open-mindedness to new challenges and frameworks
• Understanding of MVP significance and delivering high-quality outcomes under tight timelines
• Effective communication translating business complexities into solutions
• Ability to build and nurture strong client relationships
• Willingness to share expertise with team members
• Adaptability to various situations and requirements

• Write readable, scalable, and maintainable JavaScript/TypeScript code with OOP principles
• Write clear documentation for code and technical decisions
• Design and modify database structures considering long-term impacts
• Communicate feasible technical solutions and propose alternatives
• Support architecture decisions and long-term technical direction
• Identify technical and product risks, scope changes, and blockers proactively
• Maintain continuous client contact and foster good relationships
• Provide clients with options and context in complex situations
• Lead backend development by sharing knowledge and raising engineering standards
• Provide thoughtful peer code reviews

Nice to have:

• Knowledge of Scrum and Agile methodologies
• Open-source contributions
• Serverless experience
• Experience with various backend frameworks
• Experience in early product development stages
• Designing application architecture and documenting with Architectural Decision Records (ADR)