Senior Backend Engineer - Node.js / TypeScript / NestJS

Bytamic is an international IT services and Consulting company with its headquarters in Vienna, Austria and subsidiary companies in Warsaw and Poznan. We work with multinational companies and we drive digital transformation for our clients. We are truly agile, work with the latest technologies and our engineers and scrum-teams deliver state-of-the-art product development services for our clients. Delivering with highest quality standards is key to us - therefore we focus on continuous training & education of our engineers.

Role Overview

For our Client, we are looking for a qualified partner for a Senior Backend Engineer to join an international project focused on modernizing, optimizing, and stabilizing a large-scale enterprise platform serving over 1 million users.

The project focuses on improving system performance, reliability, scalability, and software quality while modernizing the existing backend architecture. The technology stack includes Node.js, TypeScript, NestJS, PostgreSQL, and React, with the platform running in a Kubernetes environment.

The main technical challenges involve event-driven architecture, advanced search capabilities, Data Lake integration, large-scale data processing, data consistency, and security in a multi-tenant environment.

We are looking for a highly experienced, hands-on engineer who combines strong backend development skills with architectural expertise and can independently identify technical challenges, propose pragmatic solutions, and take ownership of their implementation.

Seniority: Senior / Senior+ / Tech Lead

Your Responsibilities

• Analyze, refactor, and optimize an existing backend built with Node.js, TypeScript, and NestJS.
• Design and implement event-driven architecture using Apache Kafka.
• Integrate backend applications with Data Lake infrastructure and implement data synchronization using Change Data Capture (CDC)
• Design, develop, and optimize advanced search capabilities using Elasticsearch.
• Identify and eliminate PostgreSQL performance bottlenecks, including moving resource-intensive analytical operations outside the transactional database.
• Modernize data processing mechanisms handling hundreds of thousands of records.
• Design reliable business processes while ensuring transactional consistency and data integrity.
• Implement secure data isolation and access control in a multi-tenant environment.
• Refactor business logic and move it from frontend components into appropriate backend services.
• Develop and maintain unit, integration, and performance tests.
• Collaborate closely with Solution Architects, Data Engineers, DevOps Engineers, and QA teams.

Requirements

• Advanced knowledge of Node.js, TypeScript, and NestJS.
• Proven experience developing and modernizing large-scale enterprise applications.
• Strong experience designing REST APIs and system integrations.
• Hands-on experience refactoring and modernizing modular monolithic applications.
• Advanced, hands-on experience with Apache Kafka, including event-driven architecture, producers, consumers, topics, partitions, consumer groups, retry mechanisms, dead-letter queues, idempotency, and error handling. Knowledge of Transactional Outbox and Saga patterns is expected.
• Advanced, hands-on experience with Elasticsearch, including index design, mappings, analyzers, query optimization, full-text search, filtering, aggregations, and synchronization with PostgreSQL.
• Proven experience integrating Data Lake solutions and processing large datasets, including CDC, ETL/ELT pipelines, batch and incremental processing, data consistency, data quality, and synchronization latency.
• Advanced knowledge of PostgreSQL and SQL, including query optimization, indexing, execution plans, transactions, locking, and concurrency management.
• Strong understanding of software architecture principles, including modular monoliths, SOA, event-driven architecture, Domain-Driven Design, Separation of Concerns, and ACID principles.
• Experience designing secure multi-tenant applications and implementing data isolation mechanisms.
• Knowledge of authentication and authorization standards, including OAuth2 and JWT.
• Very good English communication skills.

Advanced, hands-on production experience with all three technologies - Apache Kafka, Elasticsearch, and Data Lake - is mandatory.

Nice to Have

• Experience with Kubernetes, OKD, or OpenShift.
• Familiarity with Keycloak and pg-boss.
• Knowledge of React and frontend architecture.
• Experience with financial, accounting, or other business-critical enterprise systems.
• Experience with performance testing tools such as k6.
• German language skills.

What you can expect from us

• Fully remote work
• Long-term cooperation on enterprise-scale systems
• Challenging infrastructure and automation projects
• International engineering environment
• Career development and continuous learning opportunities
• Training and education budget
• Partial reimbursement for private healthcare and Multisport
• Modern equipment
• Attractive remuneration
• Employee referral program
• Team events and integration meetings

We particularly value engineers who can independently assess technical challenges, propose pragmatic improvements, take ownership of implementation, and effectively collaborate with international engineering teams.

If you think this position can be for you, we would like to hear from you:)

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