Client 360 Full-Stack Application Developer (React.js, Javascript, GraphQL), Assistant Vice Pre[...]

State Street; Kraków; Hybrid; PLN 164,000 - 200,000; Full time

Benefits offered by this job

Permanent contract from day one

Birthday Day Off

Gold Medical Package for employees and

families

Premium life insurance

Private pension plan

Training and development programs

Volunteer time off

Well-being programs

Seniority-based additional benefits

Job summary

State Street Kraków seeks a Front-to-Back Full-Stack Application Developer focused on the services layer and a React UI. You will design, build, and maintain REST/GraphQL APIs, integrate with data stores, and collaborate across teams in a hybrid work setup.

The role emphasizes secure, scalable backend and a responsive frontend using React.js and TypeScript, with integration to various databases and messaging systems. State Street offers a permanent contract and extensive employee benefits.

Qualifications

• Bachelor’s degree in a technical field is required.
• 8–10 years of relatable experience.
• Hybrid work model in Kraków, Poland.
• Experience building service layers and APIs with modern stacks.

Responsibilities

• Design, build, and maintain service-layer components (RESTful APIs/GraphQL).
• Implement authentication/authorization, validation, error handling, and API contracts.
• Develop data access/persistence with SQL/NoSQL; optimize performance.
• Build integration patterns (Kafka/MQ) as needed.
• Develop UI with React.js, TypeScript, and modern state management.

Skills

Node.js (Express/NestJS)

TypeScript

React.js

REST/GraphQL APIs

SQL/NoSQL databases

Kafka/MQ integrations

Authentication/Authorization

Testing (unit/integration)

CI/CD & DevOps

API integration patterns

Education

B.S. degree in Computer Science, Engineering, Mathematics, or Physics

MS degree preferred

Tools

PostgreSQL

SQL Server

MySQL

MongoDB

Kafka

Docker

NestJS

Job description

Minimum Salary

Think start-up energy, backed by enterprise scale.

We are building a modern platform within a global organization - combining the agility, ownership, and engineering freedom of a start-up with the stability and funding of an industry leader. You'll work in a highly collaborative, international environment where your contributions directly shape real products used at scale.

Who We Are Looking For

Full-Stack Application Developer with a strong emphasis on the services layer (backend/API, integration, reliability) and a React.js UI.

This role can be performed in a hybrid model, where you can balance work from home and office to match your needs and role requirements.

What You Will Be Responsible For

Services Layer / Backend (Primary Focus)

• Design, build, and maintain service-layer components (RESTful APIs and/or GraphQL), including domain services, orchestration, and integrations.
• Implement authentication/authorization, request validation, error handling, and consistent API contracts.
• Develop data access and persistence logic using SQL and/or NoSQL stores; optimize queries and data models for performance and reliability.
• Build integration patterns (event-driven, async messaging, batch, streaming) as needed using tools like Kafka/MQ

UI / Front-End (React.js)

• Develop and maintain UI features using React.js, TypeScript, and modern state management patterns.
• Collaborate with design/UX to build reusable components, ensure accessibility, and deliver responsive experiences.
• Integrate the UI with backend services using well-defined API contracts; implement client-side validation and error handling.

Proficiency In One Or More Backend Stacks, Such As

• Strong experience building service layers and APIs (REST/GraphQL), including secure and scalable design.
• Node.js (Express/NestJS) and TypeScript
• Java (Spring Boot)
• Solid experience with React.js, modern JavaScript/TypeScript, component patterns, and API integration.
• Experience with databases (e.g., PostgreSQL, SQL Server, MySQL, MongoDB) and data modelling.
• Strong testing discipline: unit testing and integration testing
• Familiarity with CI/CD, code quality tools, and modern DevOps practices.

What We Value

These skills will help you succeed in this role

• Ability to collaborate with stakeholders across functions and geographies.
• Strong analytical skills, with ability to collect, absorb, and analyze information quickly and independently.
• Good written and verbal communication skills (English is a must)
• High level of engagement
• Willingness to enter into contract for employment.

Education&Other

• B.S. degree (or foreign education equivalent) in Computer Science, Engineering, Mathematics, and Physics or other technical course of study required. MS degree strongly preferred.
• Min. 8-10 years of relatable experience.

Minimum Salary

zł182,004 Annual

The minimum salary quoted above applies to the role in the primary location specified. If the candidate ultimately works outside of this primary location, the applicable minimum salary may differ.

Salary will be determined based on factors such as the position, type of work performed, individual skills, job description, working hours, diligence, initiative, self-management, length of employment, availability, and the quantity and quality of work delivered, as well as other objective and non-discriminatory criteria relevant to State Street employees.

In addition to salary, employees are eligible to be considered for discretionary annual performance-based awards.

We Offer

• Permanent contract from day one
• Additional holidays (Birthday Day Off, 3rd and 5th year anniversary Day Off)
• Gold Medical Package for employees and their families (partner and children)
• Premium life insurance package and private pension plan
• Wide range of soft skills training, technical workshops, language classes and development programs
• Opportunities to volunteer your time to company-driven initiatives, employee networks or organizations of your choice
• Variety of well-being programs
• Additional benefits available depending on the seniority of the role

About State Street

Across the globe, institutional investors rely on us to help them manage risk, respond to challenges, and drive performance and profitability. We keep our clients at the heart of everything we do, and smart, engaged employees are essential to our continued success.

We are committed to fostering an environment where every employee feels valued and empowered to reach their full potential. As an essential partner in our shared success, you'll benefit from inclusive development opportunities, flexible work-life support, paid volunteer days, and vibrant employee networks that keep you connected to what matters most. Join us in shaping the future.

As an Equal Opportunity Employer, we consider all qualified applicants for all positions without regard to race, creed, color, religion, national origin, ancestry, ethnicity, age, disability, genetic information, sex, sexual orientation, gender identity or expression, citizenship, marital status, domestic partnership or civil union status, familial status, military and veteran status, and other characteristics protected by applicable law.

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