CrawlJobs Logo
Astek Logo Astek · IT - Software Development

Fullstack Developer – Backend Background

Poland, Warsaw · Job Posted March 21, 2026
Apply Position
Job Link Share

Job Description

We are currently looking for a candidate for the position of Fullstack Developer(he/she) for our client from the biotechnology industry.

Job Responsibility

  • Backend Architecture: Design, develop, and maintain scalable and robust server-side applications using NestJS and Node.js (v18+)
  • Frontend Development: Build and maintain responsive, high-performance user interfaces using React
  • Graph Data Management: Design and manage complex data models in Neo4j, writing efficient Cypher queries
  • API Development: Develop, document, and maintain secure, well-structured RESTful APIs, as well as integrate third-party services and external systems
  • System Integration: Ensure smooth communication between backend services, frontend applications, and external APIs
  • DevOps & Tooling: Manage project dependencies and development workflows using npm or yarn, and support reliable deployment processes
  • Code Quality & Best Practices: Participate in peer code reviews, write unit and integration tests, and ensure adherence to coding standards and best practices

Requirements

  • Extensive experience with Node.js (v18 or later) and the JavaScript/TypeScript ecosystem
  • Strong understanding of NestJS, including modules, providers, controllers, and middleware
  • Proven experience building complex single-page applications (SPAs) using React, including tools such as Hooks, Context API, or state management libraries
  • Hands-on experience with Neo4j (Desktop or Server) and strong proficiency in Cypher
  • Solid background in RESTful API design and experience integrating various external APIs and third-party services
  • Comfortable working with modern development tools, including Git, NestJS CLI, and package managers such as npm or yarn

What we offer

  • Long-term collaboration
  • Technical training, certifications, and skills development
  • Competence Center mentoring
  • Clear career path
  • Employee benefits package (Multisport, private healthcare, life insurance)
  • Friendly working atmosphere, team-building events, and team-building meetings
Astek - All Job Offers

Looking for more opportunities?

Search for other job offers that match your skills and interests.

Suggested Tags: Frontend Developer Secretary Talent Manager Salesforce Administrator Data Analyst
Similar Jobs for

Fullstack Developer – Backend Background

8 matching positions

Fullstack Developer

At Optimove, we believe people are capable of more than a single job description...
Location
Location
Israel , Tel Aviv
Salary
Salary:
Not provided
optimove.com Logo
Optimove
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • B.Sc. (or higher) in computer science, or equivalent
  • 4+ years of web development, including frontend and backend
  • Hands-on experience in designing and developing large-scale highly performing applications - a must
  • Hands-on experience with relational databases (SQL)
  • Strong background in computer science fundamentals - data structures, object-oriented programming, and multi-threading
Job Responsibility
Job Responsibility
  • Develop end-to-end features in a complex, data-intensive web application
  • Write clean and maintainable code, including high coverage of unit and E2E tests
  • Provide guidance and mentoring for other team members
  • Initiate and lead infrastructure improvements and strive for excellence
Read More
Arrow Right

Senior Java Fullstack GenAI Developer

Senior Java Fullstack GenAI Developer - Vice President is a senior level positio...
Location
Location
India , Pune
Salary
Salary:
Not provided
https://www.citi.com/ Logo
Citi
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • 10+ years of progressive experience in software engineering, architecture, Application Development as Java Fullstack engineer
  • Minimum of 3+ year strong working experience in ML/GenAI, and data analytics
  • Advanced knowledge of probability, statistics and linear algebra
  • Expertise in statistical modelling, hypothesis testing and experimental design
  • Hands on experience with LLMs (Google Gemini, Open AI, Llama etc.), LangChain, LlamaIndex, Hugging Face Transformers, Knowledge graph, and Vector Databases
  • Advanced knowledge of RAG techniques is required, including expertise in hybrid search methods, multi-vector retrieval, Hypothetical Document Embeddings (HyDE), self-querying, query expansion, re-ranking, and relevance filtering etc
  • Must Have hands-on experience with GenAI application with Agentic AI, RAG approach, Vector databases, LLM’s
  • Must Have Strong Proficiency in Python, FastAPI/Flask
  • Must have Advanced NLP skills, including Named Entity Recognition (NER), Dependency Parsing, Text Classification, and Topic Modelling
  • Strong Proficiency in deep learning frameworks such as TensorFlow, PyTorch, scikit-learn, Scipy, Pandas and high-level APIs like Keras is essential
Job Responsibility
Job Responsibility
  • Partner with multiple management teams to ensure appropriate integration of functions to meet goals as well as identify and define necessary system enhancements to deploy new products and process improvements
  • Resolve variety of high impact problems/projects through in-depth evaluation of complex business processes, system processes, and industry standards
  • Provide expertise in area and advanced knowledge of applications programming and ensure application design adheres to the overall architecture blueprint
  • Utilize advanced knowledge of system flow and develop standards for coding, testing, debugging, and implementation
  • Develop comprehensive knowledge of how areas of business, such as architecture and infrastructure, integrate to accomplish business goals
  • Provide in-depth analysis with interpretive thinking to define issues and develop innovative solutions
  • Serve as advisor or coach to mid-level developers and analysts, allocating work as necessary
  • Appropriately assess risk when business decisions are made, demonstrating particular consideration for the firm's reputation and safeguarding Citigroup, its clients and assets, by driving compliance with applicable laws, rules and regulations, adhering to Policy, applying sound ethical judgment regarding personal behavior, conduct and business practices, and escalating, managing and reporting control issues with transparency
  • Fulltime
Read More
Arrow Right

Senior Java Fullstack GenAI Developer

Senior Java Fullstack GenAI Developer - Vice President is a senior level positio...
Location
Location
India , Pune
Salary
Salary:
Not provided
https://www.citi.com/ Logo
Citi
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • 10+ years of progressive experience in software engineering, architecture, Application Development as Java Fullstack engineer with strong working exposure to GenAI, and data
  • Architecture decision ownership
  • Hands-on code reviews and design reviews
  • Proven experience of below technologies: Backend: Java, Spring Boot, Microservices, REST API design
  • Frontend: Angular, Web Performance Optimization, Testing (Jest, Playwright)
  • Database & Storage: Oracle, NOSQL, PostgreSQL, Vector DBs
  • Security & Performance: OAuth2, JWT, encryption, and system optimization
  • DevOps: CI/CD, Jenkins, GitHub Actions, Docker, Kubernetes
  • Cloud: AWS (ECS, Lambda, RDS, IAM, CloudFormation)
  • Strong background in System analysis, Architecture and Application development
Job Responsibility
Job Responsibility
  • Partner with multiple management teams to ensure appropriate integration of functions to meet goals as well as identify and define necessary system enhancements to deploy new products and process improvements
  • Resolve variety of high impact problems/projects through in-depth evaluation of complex business processes, system processes, and industry standards
  • Provide expertise in area and advanced knowledge of applications programming and ensure application design adheres to the overall architecture blueprint
  • Utilize advanced knowledge of system flow and develop standards for coding, testing, debugging, and implementation
  • Develop comprehensive knowledge of how areas of business, such as architecture and infrastructure, integrate to accomplish business goals
  • Provide in-depth analysis with interpretive thinking to define issues and develop innovative solutions
  • Serve as advisor or coach to mid-level developers and analysts, allocating work as necessary
  • Appropriately assess risk when business decisions are made, demonstrating particular consideration for the firm's reputation and safeguarding Citigroup, its clients and assets, by driving compliance with applicable laws, rules and regulations, adhering to Policy, applying sound ethical judgment regarding personal behavior, conduct and business practices, and escalating, managing and reporting control issues with transparency
  • Fulltime
Read More
Arrow Right

Fullstack Engineer - Lovable Apps Platform Team

We're looking for product-minded fullstack engineers who can own end-to-end slic...
Location
Location
Sweden , Stockholm
Salary
Salary:
Not provided
lovable.dev Logo
Lovable
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • Strong fullstack background: deep comfort with TypeScript/React on the frontend and Node.js or similar on the backend
  • Experience building and operating SaaS platform features — auth flows, metering/billing pipelines, API gateways, or developer tooling
  • Product instinct: you think in user outcomes, not just API endpoints
  • Comfort working with third-party services and building clean abstractions over vendor APIs
  • Familiarity with managed cloud services (AWS, GCP) and the tradeoffs of buy-vs-build
  • Experience with observability, logging, or metering systems is a strong plus
  • You've shipped features in fast-moving, high-ownership environments where you wore multiple hats
  • Experience with DNS, TLS/SSL automation, and custom domain provisioning at scale
Job Responsibility
Job Responsibility
  • Create UX for our users to build with Apps Platform features
  • Build and own platform services like identity, logging, metering, workflow engine, object storage, secrets
  • Create abstraction layers for deep integrations with key partners and vendors
  • Fulltime
Read More
Arrow Right

Senior Full Stack Engineer

We are looking for a Senior Fullstack Engineer with strong backend expertise to ...
Location
Location
Netherlands , Amsterdam
Salary
Salary:
Not provided
levy-professionals.com Logo
Levy Professionals
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • Senior-level experience in backend or fullstack engineering
  • Strong backend development background within distributed systems
  • Proven experience with AWS serverless architectures
  • Hands-on experience with Lambda, DynamoDB, SNS, and SQS
  • Strong TypeScript development experience
  • Experience with Infrastructure as Code, preferably AWS CDK
Job Responsibility
Job Responsibility
  • Design, build, and maintain scalable backend services using Node.js
  • Develop event-driven applications using AWS serverless technologies
  • Work extensively with AWS Lambda, DynamoDB, SNS, and SQS
  • Build and maintain Infrastructure as Code using AWS CDK
  • Write clean, maintainable, and production-grade TypeScript
  • Contribute to architectural discussions and technical improvements
  • Collaborate with existing engineering teams to deliver value quickly
  • Support reliable deployments and distributed system performance
  • Fulltime
Read More
Arrow Right

Software Engineer II - Fullstack

Microsoft is a company where passionate innovators come to collaborate, envision...
Location
Location
Canada , Vancouver
Salary
Salary:
85000.00 - 166800.00 CAD / Year
https://www.microsoft.com/ Logo
Microsoft Corporation
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • Bachelor's Degree in Computer Science or related technical field AND 2+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR equivalent experience
  • 2+ years of experience with creating responsive and accessible UI using TypeScript, Angular, RxJs, or equivalent
  • 2+ years of backend development experience (designing and working with APIs, databases, etc.)
  • Ability to meet Microsoft, customer and/or government security screening requirements are required for this role
  • Must pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter
Job Responsibility
Job Responsibility
  • Deliver world-class user experiences and cloud services at scale to customers in collaboration with architects, UX designers, and product managers
  • Write secure, performant, well-tested code across web clients and service-side components integrating with LLM-based agents
  • Ensure implementation resiliency, security, reliability, latency, and cost using observability and operational practices
  • Act as DRI for key services and drive durable fixes
  • Participate actively in code reviews, bug/issue triage with other feature teams, and support well informed decisions towards business and engineering goals
  • Maintain customer focus, considering current and future needs when designing and implementing features
  • Collaborate effectively within the team and with partner teams across Microsoft
  • Embody our culture and values
  • Fulltime
Read More
Arrow Right

Senior Software Engineer

Microsoft is looking for a Senior Software Engineer to join Copilot Studio’s AI ...
Location
Location
United States , Redmond
Salary
Salary:
119800.00 - 234700.00 USD / Year
https://www.microsoft.com/ Logo
Microsoft Corporation
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • Bachelor's Degree in Computer Science or related technical field AND 4+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python
  • OR equivalent experience
  • Ability to meet Microsoft, customer and/or government security screening requirements
  • Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter
Job Responsibility
Job Responsibility
  • Collaborates with stakeholders to determine user requirements
  • Drives design documentation and dependency identification
  • Builds, optimizes, debugs, refactors, and maintains high-quality code
  • Designs and runs experiments to evaluate effectiveness of changes
  • Partners with PMs to deliver project and release plans
  • Acts as DRI and participates in on-call rotations
  • Proactively adopts new technologies to improve reliability, performance, and observability
  • Mentors other engineers and provides technical leadership while embodying Microsoft’s culture and values
  • Fulltime
Read More
Arrow Right

Senior Software Engineer- Fullstack

Microsoft’s Azure Data engineering team is leading the transformation of analyti...
Location
Location
Canada , Vancouver
Salary
Salary:
114400.00 - 203900.00 CAD / Year
https://www.microsoft.com/ Logo
Microsoft Corporation
Expiration Date
Until further notice
Flip Icon
Requirements
Requirements
  • Bachelor's Degree in Computer Science or related technical field AND 4+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR equivalent experience
  • Ability to meet Microsoft, customer and/or government security screening requirements are required for this role
  • This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter
  • Master's Degree in Computer Science or related technical field AND 6+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR Bachelor's Degree in Computer Science or related technical field AND 8+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR equivalent experience
  • Experience with cloud service development
  • Technical problem solving and debugging skills
Job Responsibility
Job Responsibility
  • Design and implement scalable backend services, ensuring high availability, low latency, and reliability across multi-cloud environments
  • Drive end-to-end ownership of components, from requirement gathering through development, testing, deployment, and post-production quality assurance
  • Collaborate across disciplines—engineering, PM, and customer teams—to deliver features that simplify data access and governance for global customers
  • Embed security, compliance, and observability into every stage of development to uphold operational excellence and governed self-service
  • Innovate with AI-first development practices, leveraging modern tech stacks (C#, Service Fabric, Spark, Kusto) to accelerate quality and velocity
  • Embody our culture and values
  • Fulltime
Read More
Arrow Right