Jobs Backend

At P2Bid, we build multiplayer games where every game mechanic is powered by a fast, reliable, and scalable backend.
 

We're looking for a Senior Python Developer with 5+ years of commercial Python experience, including 3+ years building asynchronous backend services under real production load.
 

About the role:

We're looking for an engineer who goes beyond implementation and takes ownership of technical decisions.

You'll be responsible for designing and evolving core backend services, owning critical parts of the system, reviewing code, and helping shape the technical direction of the product. We value engineers who think about reliability, scalability, maintainability, and long-term architecture—not just delivering features.
 

Requirements

• 5+ years of commercial Python development experience.
• 3+ years building high-load asynchronous backend services.
• Strong knowledge of Python 3.11+, async/await, the event loop, and asynchronous programming principles.
• Hands-on experience with asynchronous web frameworks such as FastAPI, Starlette, aiohttp, Litestar, or similar.
• Deep understanding of asyncio: gather, TaskGroup, task cancellation, timeouts, backpressure, and concurrency patterns. You understand why a silently failed background task is a production incident.
• Strong typing as a standard development practice. Experience with mypy or pyright, Protocols, Generics, and modern Python typing.
• Excellent SQL skills, including JOINs, indexes, transactions, and extensive experience with PostgreSQL.
• Strong understanding of PostgreSQL locking mechanisms (FOR UPDATE, SKIP LOCKED), transaction isolation levels, deadlocks, and query execution plans.
• Experience with SQLAlchemy (ORM or Core) or another mature ORM.
• Confident writing automated tests with pytest, fixtures, parametrization, and dependency mocking.
• Experience working with Docker, Git, and code reviews through Merge/Pull Requests.
• Production experience with message brokers such as Kafka, RabbitMQ, NATS, or similar. You've debugged real production issues—not just studied the concepts.
• Practical experience building distributed systems, including at-least-once delivery, idempotency, deduplication, and understanding why exactly-once delivery is not achievable over the network.
• Experience working with business-critical domains such as payments, billing, accounting, order management, inventory, or any system where mistakes have financial consequences.
• Strong understanding of failure scenarios. For example, you know how to handle cases where a request was sent but no response was received—and why a naive retry may be worse than a failure.
• Ability to perform meaningful code reviews, focusing on architecture, reliability, maintainability, and engineering quality—not just code style.
• English sufficient for reading technical documentation, writing code comments, and technical documentation. Spoken English is a plus but not required.
   

Tech Stack

• Python 3.12
• FastAPI
• PostgreSQL
• MongoDB
• NATS / JetStream
• Docker
• Kubernetes

We also use dishka (dependency injection), adaptix (mapping), FastStream (message broker abstraction), ty (typing), and uv (dependency management). You don't need prior experience with these libraries—they're based on familiar concepts and are easy to learn. During interviews, we focus on your understanding of asynchronous programming, SQL, distributed systems, and engineering trade-offs, not on knowledge of specific libraries.
 

If you meet most of the requirements, we'd love to hear from you—even if some technologies in our stack are new to you.

Project description

Developed product is the leading software system in Energy domain covering all aspects of Oil&Gas production from geological exploration to optimization of ongoing production. Our technology solution helps geologists and geophysicists to research, visualize and interpret large volumes of geological data.
Our project is stable, long-term and constantly adopts new technologies such as Java 11, Cloud and GPU computing.
Work supposes close cooperation with Customer team located in Houston and following Agile principles.
Our team is senior, supportive and friendly.

Responsibilities

Learn technologies used on the project;

Explore existing code base;

Start performing project tasks.

Skills

Must have

Strong Java Core;

Algorithms: sorting, optimization;

Intermediate English.

Nice to have

Experience in desktop applications development using Java.

Git repository link of candidate's work would be helpful.

Kyivstar is seeking an experienced Azure Cloud Solution Architect to join our dynamic team and drive the establishment of an innovative Cloud Technology Center of Excellence.

This role requires building Data&AI solutions based on Azure Cloud.

The Center of Excellence will focus on cloud Infrastructure migration services including network, security and Analytical Professional Services. The primary objective is to promote cloud technologies and migration services to B2B/B2G customers regionally and beyond.

Requirements:

• 5 years of hands-on experience designing and implementing cloud-based data solutions, focusing on Azure/AWS services (Data Analytics, Data Platforms, Data Model)
• Strong experience in implementing and migrating on-premises or cross-cloud workloads to Azure, experience in complex IT solutions and Hybrid Cloud solution projects.
• Experience in conducting solution assessments and selecting optimal cloud/hybrid architecture approaches to enhance and migrate existing infrastructure that seamlessly integrate on-premises and cloud-based resources, leveraging the strengths of both environments.
• Proficiency in conducting detailed TCO calculations and providing Cloud cost-effective architectural recommendations.
• Proven ability to design complex Solutions based on future-proof architectures that can adapt to evolving business needs over time.
• Proficient in architecting, deploying, and managing various Cloud services, including App Service, Data Factory, Fabric, Entra ID, EC2, EKS, S3, Glue, EMR, Lambda, VPC, RDS, KMS and IAM.
• Experience in provisioning cloud networking architectures, utilizing Virtual Networks, VPN, Express Route/Direct Connect, Network Security Groups, and Load Balancers.
• Knowledge of security practices centered around cloud - IAM, WAF, AWS Shield, Security Hub, GuardDuty
• Proven ability to excel in customer-facing roles, with exceptional communication and interpersonal skills
• English – Fluent
• Certificates – Azure/AWS Certified Solutions Architect – Professional is a plus

Responsibility:

• Lead Cloud Data Solutions team
• Collaborate with cross-functional teams to create and implement strategies for promoting Kyivstar’s Cloud technologies and migration services.
• Engage directly with customers, provide infrastructure/solutions assessments to understand their technical needs, address concerns, and presenting cloud-based solutions effectively.
• Design end-to-end solutions (infra, network, security) including TCO calculations leveraging Cloud services to meet customer requirements and industry best practices.
• Develop and implement scalable and secure cloud architectures that align with business goals and compliance standards.
• Implement robust security measures, including access controls, encryption, and monitoring, to ensure the integrity and confidentiality of customer data in the Cloud environment.
• If you are a skilled Architect professional with a strong background in Azure services, a passion for innovation, and the drive to lead a team in a customer-centric environment, we encourage you to apply.

We offer:

• A competitive salary.
• Great possibilities for professional development and career growth.
• Medical insurance.
• Life insurance
• Friendly & Collaborative Environment

We understand the importance of the protection of your Applicants Data and are committed to using good practices in how we handle such Data. Our processes are designed to ensure that we collect, process, use and transfer that data in accordance with applicable local law. By clicking on "Apply for this job", you confirm that you have read, understood and explicitly agree to the our Applicants Privacy Policy.

• The project focuses on developing advanced software solutions for the oil and gas industry, supporting key stages of the reservoir lifecycle, including exploration, development, production, operations, maintenance, and abandonment.
  
  The successful candidate will join the Information Management and Platform Technologies Development team and contribute to the design and development of next-generation software products. The role offers an opportunity to work with modern technologies, apply innovative ideas, and build solutions used in complex energy industry environments.

   

• Responsibilities:

  Key Responsibilities/Accountabilities:
  - Knowledge of software engineering best practices (including requirements analysis, system design, modularity, version control, testing, documentation, etc.) for productivity, collaboration, quality, and maintainability.
  - Knowledge of how a component fits into a larger ecosystem of products and services.
  - Understanding of how these different pieces work together, and communicate with them (using library calls, REST APIs, database queries, etc.)
  - Know how to build appropriate interfaces for components that others will depend on. Knowledge of basic system design patterns to avoid bottlenecks and let your algorithms scale well with increasing volumes of data.
  - Perform research and development tasks.
  - Expected to design, code, test, do troubleshooting and document engineering systems applications by following the software development lifecycle.
  - Accomplishes engineering and organization mission by completing related results as needed.
  - Updates job knowledge by studying state-of-the-art development tools, programming techniques, and computing equipment; participating in educational opportunities; reading professional publications; participating in professional organizations.

   

• Mandatory Skills Description:

  - Degree in Computer Science, Engineering, or equivalent. Master's preferred
  - Software Development Fundamentals
  - Strong understanding of Object-Oriented Design and Principles
  - 5+ years of professional experience with Java and Angular
  - Build & CI/CD: Git Ci/CD, Helm
  - Database background: Posgtess
  - REST API Express
  - Hapi
  - Self-motivated
  - Problem Solving skills
  - Works well within a team
  - Excellent communication skills

   

• Nice-to-Have Skills Description:

  - Web front-end technologies and tools: HTML5, CSS, SASS, JavaScript, Angular 16+, Angular CLI, Typescript, NPM, and VS Code.
  - Web back-end technologies: RESTful APIs using Microservices (NodeJS, C#, C++, Python), Express, JSON, OData, Web Sockets, and Java EE.
  - Testing: JEST, Karma/Jasmine, E2E testing with Protractor.
   MAVEN, Jenkins & Ansible, Containerization.
  - Cloud: Knowledge in cloud technologies (Azure and Amazon)

   

• Languages:

  • English: B2 Upper Intermediate

     

• Processing Steps

  CVR -> TI1(Java) -> TI2(Angular) -> PMI -> CLCVR -> CLI

• Developed product is the leading software system in Energy domain covering all aspects of Oil&Gas production from geological exploration to optimization of ongoing production. Our technology solution helps geologists and geophysicists to research, visualize and interpret large volumes of geological data.
  Our project is stable, long-term and constantly adopts new technologies such as Java 11, Cloud and GPU computing.
  Work supposes close cooperation with Customer team located in Houston and following Agile principles.
  Our team is senior, supportive and friendly.

   

• Responsibilities:

  - Learn technologies used on the project;
  - Explore existing code base;
  - Start performing project tasks.

   

• Mandatory Skills Description:

  - Strong Java Core;
  - Algorithms: sorting, optimization;
  - Upper Intermediate English.

   

• Nice-to-Have Skills Description:

  Experience in desktop applications development using Java.
  Git repository link of candidate's work would be helpful.

   

• Languages:
  • English: B2 Upper Intermediate

The project focuses on developing advanced software solutions for the oil and gas industry, supporting key stages of the reservoir lifecycle, including exploration, development, production, operations, maintenance, and abandonment.

The successful candidate will join the Information Management and Platform Technologies Development team and contribute to the design and development of next-generation software products. The role offers an opportunity to work with modern technologies, apply innovative ideas, and build solutions used in complex energy industry environments.

• Responsibilities:

  Key Responsibilities/Accountabilities:
  - Knowledge of software engineering best practices (including requirements analysis, system design, modularity, version control, testing, documentation, etc.) for productivity, collaboration, quality, and maintainability.
  - Knowledge of how a component fits into a larger ecosystem of products and services.
  - Understanding of how these different pieces work together, and communicate with them (using library calls, REST APIs, database queries, etc.)
  - Know how to build appropriate interfaces for components that others will depend on. Knowledge of basic system design patterns to avoid bottlenecks and let your algorithms scale well with increasing volumes of data.
  - Perform research and development tasks.
  - Expected to design, code, test, do troubleshooting and document engineering systems applications by following the software development lifecycle.
  - Accomplishes engineering and organization mission by completing related results as needed.
  - Updates job knowledge by studying state-of-the-art development tools, programming techniques, and computing equipment; participating in educational opportunities; reading professional publications; participating in professional organizations.

• Mandatory Skills Description:

  - Degree in Computer Science, Engineering, or equivalent. Master's preferred
  - Software Development Fundamentals
  - Strong understanding of Object-Oriented Design and Principles
  - 5+ years of professional experience with Java and Angular
  - Build & CI/CD: Git Ci/CD, Helm
  - Database background: Posgtess
  - REST API Express
  - Hapi
  - Self-motivated
  - Problem Solving skills
  - Works well within a team
  - Excellent communication skills

We're looking for a Middle+/Senior Backend Developer - first and foremost a strong, well-rounded backend engineer. The role splits roughly 70/30: 70% designing and maintaining our external integrations (casino operators and partner platforms), 30% general backend/platform work and system design.

🚀 What you'll do

• Design, build, and maintain integrations with casino operators and partner platforms (wallet/transaction APIs, game launch, and reporting contracts), owning the full lifecycle from contract design to production monitoring;
• Build resilient integration layers: retries, idempotency, timeouts, error mapping, and graceful degradation when a third party misbehaves;
• Contribute to core backend services and platform features - APIs, messaging flows, data models, shared modules;
• Take part in slot game development on our game logic platform - implementing game mechanics and mathematics alongside the core team;
• Define and improve integration testing practices: contract testing, mocking/stubs, e2e, and stress/load testing;
• Work closely with Game Logic, Product, and DevOps teams to keep integration contracts stable as the platform evolves;
• Participate in code reviews, technical decisions, and architecture discussions across the backend.

🧩 What you bring

• 3-5+ years of backend development experience with Node.js + TypeScript, including ownership of non-trivial systems;
• Proven experience designing and maintaining external integrations (REST/HTTP, XML/SOAP, RPC-style, or webhook-based);
• Solid understanding of modular, service-oriented backend architecture, ideally from enterprise or scale-up environments;
• Practical experience with message brokers (RabbitMQ or Kafka) and event-driven, queue-based design;
• Strong grasp of integration testing approaches: contract testing, mocking, e2e, and stress testing;
• Confident with PostgreSQL and Redis, CI/CD, Git, and monitoring/observability tools (Grafana, Loki, Tempo);
• Comfortable with AWS, Docker, and Kubernetes for containerized deployments.

💎 Nice to have

• Experience in iGaming, gambling platforms, or RNG/game provider integrations;
• Familiarity with ArgoCD and GitOps workflows.

🎁 Benefits

• 21 vacation days + 2 extra day-offs annually;
• 12 paid sick days;
• Fully remote format - work from anywhere you feel productive;
• Flexible schedule: start your day anytime between 08:00-11:00 CET;
• Fixed budget for health insurance and gym/fitness;
• Provided all required work equipment;
• Zero bureaucracy and direct communication with founders and C-level;
• Minimal meetings, async-friendly workflow;
• Startup energy: fast motion, creativity, and tight-knit communication;
• Business trips and team meetups several times per year;
• Multiple salary payout options (flexible formats);
• …And many more perks unlocked after we hit break-even.

A backend-focused engineering position on a transformation project for an international travel company. The engineer will own features end-to-end - from planning and design through building, testing, and release.

Key Responsibilities 

-Own features end-to-end (plan, design, build, test, release) 

-Build and maintain Ruby on Rails systems 

-Contribute to full-stack work (Rails-heavy, with frontend involvement as needed) 

-Write tested, high-quality code 

-Use AI coding agents to maximize efficiency 

-Participate in code reviews 

-Maintain systems and resolve production issues 

-Collaborate with Product, Design, and Quality Engineering teams

Required Qualifications 

-Proficiency in Ruby on Rails with production experience 

-Strong database schema design and data modeling skills 

-RESTful API design experience 

-PostgreSQL and AWS infrastructure knowledge 

-Demonstrable experience with AI coding agents, or strong enthusiasm to adopt them 

-Good English 

-Team-oriented with strong communication skills 

-Pragmatic about speed/quality/scope tradeoffs

Tech Stack 

-Ruby on Rails, PostgreSQL, AWS, Next.js, Vercel. Trunk-based development with CI/CD and multiple daily deployments. 

Nice to Have 

-E-commerce or travel platform experience 

-An eye for UX/design 

-Travel enthusiasm

We offer:

• Attractive financial package

• Challenging projects

• Professional & career growth

• Great atmosphere in a friendly small team

We are looking for a Middle/ Middle+ PHP Developer to join a long-term project focused on building and evolving a complex data-processing platform in the Construction Technology domain.

This role is centered around backend architecture, high-load systems, and real-time data processing. You will be responsible for designing scalable services, managing asynchronous data flows, and ensuring reliable ingestion and processing of IoT device data.

The platform plays a key role in workforce tracking, operational efficiency, and automation of field processes. It processes large volumes of real-time data and applies complex business logic for workforce scheduling and analytics.

This is a backend-focused role with high ownership and impact on system architecture and performance.
 

Benefits

• Opportunity to solve complex architectural and high-load challenges
• Professional growth within a scaling tech company
• High-impact role in a real-world IoT and data-driven product
• Work with modern backend technologies and distributed systems
• Remote-first environment with flexibility and autonomy
   

About the Client

International product company in the Construction Technology domain, focused on automating workforce management processes through IoT and cloud-based solutions.

The product replaces manual time tracking with automated data collection, improves payroll accuracy, and enables real-time tracking of workforce operations and analytics.
 

About the Project

The platform’s core processing system is responsible for IoT data ingestion, real-time processing, and advanced workforce scheduling logic.

The system provides real-time dashboards and analytics for operational decision-making.
 

Location: United States

Duration: long-term
 

Requirements

• 3+ years of commercial experience with PHP in backend development
• Strong expertise in Laravel and its ecosystem in production environments
• Deep knowledge of PostgreSQL, including optimization, indexing, and schema design
• Experience with Laravel Jobs and queue systems (Redis, SQS)
• Solid understanding of RESTful APIs and third-party integrations
• Experience with Eloquent ORM performance tuning and N+1 query prevention
• Familiarity with Docker and containerized development
   

Additional Requirements

• Strong understanding of SOLID principles and clean code practices
• Strong problem-solving skills and attention to detail
• Experience working in Agile/Scrum environments
• Upper-Intermediate (B2+) English level for spoken communication
   

Responsibilities

• Design and implement scalable backend services and APIs
• Architect and evolve backend systems for high-load environments
• Optimize complex database queries to handle large volumes of real-time data
• Build and manage asynchronous processing using queues and background jobs
• Ensure reliable ingestion and processing of IoT-driven data streams
• Conduct code reviews and maintain high standards of code quality
• Refactor legacy components into modern, maintainable service patterns
• Collaborate with product and engineering teams to translate business requirements into technical solutions
   

🇺🇦 Additional Notes

• We consider candidates both in Ukraine and abroad
• For specialists based in Ukraine, we provide the option of official booking (reservation)

We are looking for a strong Backend Developer for a high-load project connected with Android infrastructure, reverse engineering, network traffic analysis, and processing large amounts of data.

The main backend is built on Node.js, so strong knowledge of JavaScript and TypeScript is required.

Responsibilities

• Develop and maintain backend services using Node.js / TypeScript.
• Work with high-load and distributed systems.
• Design systems for storing and processing large amounts of data.
• Work with PostgreSQL, ClickHouse, and Redis.
• Optimize database queries, indexes, and data structure.
• Work with:
  • replication;
  • sharding;
  • partitioning;
  • distributed data;
  • high availability;
  • fault tolerance.
• Work with Kubernetes infrastructure.
• Find and fix performance problems in backend, databases, and infrastructure.
• Analyze network traffic and application communication.
• Work with traffic sniffing and proxy tools.
• Understand how mobile applications communicate with backend services and APIs.
• Analyze requests, responses, headers, payloads, tokens, and sessions.
• Work with existing code and systems with limited documentation.
• Find technical problems and propose solutions independently.
• Work with distributed workers, services, and nodes.

Required Skills

Backend

• Strong experience with Node.js.
• Strong knowledge of JavaScript.
• Strong knowledge of TypeScript.
• Good understanding of async programming.
• Understanding of Node.js event loop.
• Experience with REST API and WebSocket.
• Experience with high-load backend systems.

Databases

• Strong experience with PostgreSQL.
• Strong experience with ClickHouse.
• Strong experience with Redis.
• Good understanding of:
  • indexes;
  • query optimization;
  • query plans;
  • replication;
  • sharding;
  • partitioning;
  • distributed databases;
  • data consistency;
  • high availability.

Experience with large databases and high traffic is very important.

Infrastructure

• Kubernetes.
• Docker.
• Linux.
• Experience with cluster systems.
• Understanding of networking.
• Understanding of load balancing.
• Understanding of horizontal scaling.
• Ability to find CPU, RAM, disk, and network bottlenecks.
• Experience with logs and monitoring.

Reverse Engineering / Network Analysis

• Understanding of Android reverse engineering.
• Understanding of Android architecture.
• Experience with traffic sniffing.
• Good understanding of HTTP / HTTPS.
• Understanding of TLS.
• Experience with proxy-based traffic analysis.
• Understanding of authentication, sessions, cookies, and tokens.

Important

We are not looking for a developer who only has experience with simple CRUD applications.

The candidate should understand the full system:

application → network → backend → databases → infrastructure

The developer should be able to work independently, research technical problems, understand existing systems, and find solutions even when documentation is limited.

Level

Strong Middle / Senior Backend Developer

Experience in these areas will be a plus:

• high-load systems;
• distributed systems;
• reverse engineering;
• network traffic analysis;
• large-scale data processing;
• complex or undocumented APIs;
• systems with many workers and nodes.

Looking to take your .NET expertise to the next level while working on high-impact FinTech solutions? This role offers the chance to contribute to scalable, cloud-native systems that empower thousands of businesses worldwide.
We’re seeking a Senior .NET Developer to join our team, collaborating with talented engineers, product managers, and designers to deliver innovative financial technology.
At Sigma Software, we work with some of the most forward-thinking companies in the industry. This opportunity will let you grow professionally while making a tangible difference in a fast-paced, regulated environment.

CUSTOMER

Our customer is a leading FinTech company providing embedded financing solutions for platforms and marketplaces. Their mission is to enable businesses to offer flexible credit products to customers, helping SMEs access funding quickly and efficiently.
The customer is recognized for innovation in embedded finance, serving thousands of businesses globally and partnering with major platforms. They operate in a regulated environment with a strong focus on scalability, performance, and security.

PROJECT

The project involves enhancing and expanding customer’s embedded finance platform, which integrates directly into partner services to deliver fast, flexible funding to SMEs. You’ll work on a modern tech stack, building features that improve customer and partner experiences while ensuring reliability in production.
Key Technologies: C#, .NET Core, Angular 18, AWS, CI/CD, Docker/Kubernetes, Kafka/RabbitMQ, Datadog, relational & NoSQL databases

Job Description

• Design, build, and deliver features and projects across C#, .NET Core, and Angular stack
• Write clean, maintainable, and well-tested code (unit/integration/e2e)
• Take ownership of features from requirements breakdown to deployment
• Deploy and monitor services in AWS cloud-native environments
• Handle production issues and incidents with accountability
• Collaborate with Product, Design, and Engineering teams in Agile practices
• Contribute to continuous improvement of systems and processes

Qualifications

• 5+ years of experience in software development with strong OOP and system design skills
• Solid hands-on experience with .NET (C#) and Angular
• Understanding of software testing concepts and practices
• Expertise in cloud-native and DevOps practices (CI/CD, automation, monitoring)
• Experience with relational and NoSQL databases
• Knowledge of non-functional requirements (performance, security, availability)
• Proven experience in FinTech, payments, banking, or regulated financial environments
• Upper-Intermediate English level or higher

WILL BE A PLUS

• Experience with Docker/Kubernetes
• Familiarity with event-driven architectures (Kafka, RabbitMQ)
• Proficiency with observability tools (Datadog or similar)
• Knowledge of domain-driven design (DDD) and complex domain modeling

PERSONAL PROFILE

• Growth mindset, curiosity, and proactivity
• Strong problem-solving skills balancing complexity and simplicity
• Feedback-oriented, open to giving and receiving constructive input
• Ownership & accountability in delivering commitments
• Team player with strong collaboration skills
• Adaptability to changing priorities
• Excellent communication skills across disciplines

Domain: Banking & Finance
Experience: 5+ years
Project Duration: August, 2026 – November, 2026(to be extended)
Format: Hybrid
Location: Kraków, Poland

About the Project

We are looking for a Python Developer with AI expertise to join a team of engineers building strategic AI and machine learning solutions that are transforming the Credit and Lending industry.

Working in a dynamic, innovative, and well-established environment, the selected specialist will collaborate closely with business stakeholders to deliver impactful, production-grade AI solutions.

This role is a great fit for an engineer who enjoys leading technical initiatives and applying modern AI technologies to solve complex business challenges.

Responsibilities

• Design, develop, and maintain clean, scalable, and well-tested software solutions
• Lead the architecture and implementation of AI/ML systems, ensuring reliability, scalability, and alignment with long-term platform goals
• Take ownership of major AI initiatives from solution design through deployment and operationalization
• Support and mentor other engineers, promoting engineering excellence, collaboration, and continuous learning
• Help define and promote engineering standards, AI governance practices, and responsible AI principles across the organization
• Contribute to the technical roadmap by researching, evaluating, and prototyping emerging technologies, including advanced RAG approaches, LLM optimization techniques, and agent-based systems
• Collaborate with cross-functional stakeholders to translate business needs into effective technical solutions and clearly communicate complex concepts
• Build advanced AI-powered applications using Retrieval-Augmented Generation (RAG), vector databases, and large-scale financial datasets

Requirements

• 5+ years of strong commercial experience with Python
• At least 6–12 months of hands-on experience within the broader AI/ML ecosystem
• Practical experience with relational databases such as PostgreSQL, vector databases, key-value stores such as Redis, and Pub/Sub messaging systems
• Deep understanding of microservices architecture, API design, observability, and concurrent/distributed systems
• Ability to make and drive architectural decisions in complex technical environments
• Strong knowledge of modern LLM architectures and hands-on experience adapting and fine-tuning models for domain-specific use cases
• Practical expertise in Retrieval-Augmented Generation (RAG), prompt engineering, and related generative AI techniques

Nice to Have

• Exposure to Java, particularly for integration and middleware-related tasks

Tech Stack

• Python
• AI / Machine Learning
• PostgreSQL
• Redis
• Microservices
• APIs
• LLMs
• RAG

Location

• Hybrid from Kraków, Poland
• Important: the client requires office visits in Kraków 8 days per month

Domain: Banking & Finance
Experience: 5+ years
Project Duration: August, 2026 – November, 2026(to be extended))
Format: Hybrid
Location: Kraków, Poland

About the Project

We are looking for a Java Developer with React experience to join a team developing and supporting modern, production-grade applications within the banking and finance domain.

The role combines backend development with Java, frontend development with React, API integration, and database technologies. The selected specialist will contribute to system design, application improvements, automation initiatives, and the delivery of scalable and reliable technical solutions.

Responsibilities

• Contribute to software architecture and system design initiatives
• Lead UI enhancements and improvements to strengthen user experience and application reliability
• Develop solutions in line with established design patterns and engineering best practices
• Analyze business and technical requirements and recommend effective, scalable solutions
• Create clear, detailed, and maintainable technical documentation for applications and services
• Build prototypes and proof-of-concepts to validate technical ideas, designs, and approaches
• Manage application and infrastructure changes throughout the service management lifecycle
• Drive automation initiatives and continuous improvements across service management processes
• Provide timely customer support by troubleshooting and resolving technical issues
• Collaborate closely with customers and stakeholders to understand requirements and deliver suitable technical solutions

Requirements

• 5+ years of hands-on experience developing production-grade applications within the Java ecosystem, including frontend development with React
• Strong expertise in Java development and Web API implementation
• Experience building scalable, secure, and high-performance backend systems
• Strong troubleshooting and problem-solving skills, particularly in fast-paced or high-pressure production environments
• Solid database design and SQL expertise, especially with SQL Server
• Advanced experience with T-SQL scripting, query optimization, and performance tuning
• Practical experience with DevOps practices, including CI/CD
• Strong understanding of the full Software Development Life Cycle (SDLC), including requirements analysis, system design, development, testing, deployment, and maintenance
• Excellent analytical skills, attention to detail, and the ability to solve complex technical challenges
• Strong communication and collaboration skills across technical and non-technical teams
• Fluent English

Tech Stack

• Java
• React
• Web APIs
• API Governance & Integration
• SQL Server
• SQL / T-SQL
• PL/SQL
• DevOps
• CI/CD
• SDLC

Location

• Hybrid from Kraków, Poland
• Important: the client requires office visits in Kraków 8 times per month

Місія ролі:
Розробляти прикладні AI-продукти та сервіси: backend, frontend, API, інтеграції з LLM/ML models, RAG-пайплайни, workflow automation, evaluation logic та production-ready функціональність для користувачів. Це роль не дослідника Data Science, а інженера, який перетворює AI capability у працюючий продукт.

Обов’язки:
-Розробка AI-enabled web applications та internal tools.
-Побудова backend API для AI-сервісів.
-Інтеграція LLM, embeddings, vector search, document pipelines.
-Реалізація RAG/workflow/agent-like сценаріїв там, де це виправдано.
-Побудова UI для користувачів, операторів, аналітиків або адміністраторів.
-Впровадження access control, audit trail, security controls.
-Підготовка технічних прототипів і доведення їх до production-ready стану.
-Спільна робота з BA над уточненням вимог.
-Спільна робота з DevOps/MLOps щодо deployment та monitoring.
-Спільна робота з AppSec щодо threat modeling і security testing.

Вимоги:
- 2+ роки software engineering досвіду;
- Досвід backend-розробки на Python, Go, Java, Node.js або .NET.
- Досвід frontend-розробки: React, Next.js, Angular або Vue.
- Практичний досвід з REST/gRPC API, authN/authZ, role-based access, audit logging.
- Досвід з PostgreSQL або іншими relational DB.
- Розуміння асинхронної обробки: queues, workers, schedulers, event-driven flows.
- Практичний досвід інтеграції з LLM API або open-source LLM.
- Вміння писати тести, робити code review, працювати з CI/CD.
Бажано:
- Досвід RAG: embeddings, vector DB, chunking, retrieval, reranking, source attribution.
- Досвід з LangChain, LlamaIndex, Haystack або власними lightweight orchestration-підходами.
- Досвід з LLM evaluation: golden datasets, regression tests, hallucination checks, prompt/version control.
- Досвід з document processing: OCR, PDF parsing, structured extraction.
- Досвід із secure coding та OWASP ASVS/API Security.
- Досвід побудови internal tools, dashboards, workflow automation.

Умови для цивільних:
-Офіційне працевлаштування
-Офісна робота, Київ, Центр
-Можливе бронювання
 

Умови для чинних військових:
-Військова служба
-Служба в Києві (житло не надається), Центр, Київ
-Повне грошове забезпечення для тилової посади

Ajax Systems, an international tech company and the largest manufacturer of security systems in Europe.

We’re looking for Java Developer to join us and continue the evolution of a product that we love. The team focuses on the B2B segment at Ajax Systems. It develops software solutions for business partners, supports applications for monitoring and installation companies, and develops a tablet application for rapid response teams.

Required skills:

• 8+ years of commercial experience in backend development with Java in an enterprise environment.
• Strong understanding of Java Concurrency and hands-on experience with concurrent programming in production systems.
• Solid understanding of SOA, microservices and event-driven architecture.
• Practical experience with cloud computing platforms.
• Experience building and supporting high-load, scalable and highly available systems;
• Hands-on experience with messaging brokers.
• Strong understanding of modern backend infrastructure, NoSQL, key-value databases and in-memory storage solutions.
• Practical experience with Kubernetes.
• Experience with Git, Gradle or othet CI/CD tools.
• Strong knowledge of unit testing and automated testing approaches.

Would be a plus:

• experience with these technologies: Redis, Netty, Akka, NATS, AWS, Kafka, MongoDB, gRPC.
• Practical experience with Kotlin.
• Desire to grow into a team leadership role.

What you will do:

• design and develop core backend services and data pipelines for the product line.
• Build clean, maintainable, and production-ready code with a strong focus on quality.
• Contribute to backend architecture, drive technical decisions and document solutions for reliable deployment and operations.
• Ensure proper test coverage with unit and integration tests.
• Take ownership of performance, scalability and cost efficiency within your domain.
• Maintain production reliability through monitoring, alerting, dashboards, and runbooks.
• Investigate and resolve production issues, including deep-dive analysis of complex cases.
• Work in a strong engineering culture with testing, continuous delivery and DevOps practices.
• Collaborate closely with product and engineering teams to deliver new features and improve existing services.

Why this role is interesting:

• opportunity to work on high-load backend systems and distributed architecture.
• Real impact on core product development and architectural decisions.
• Modern technology stack and engineering-driven environment.
• Challenging tasks where performance, reliability and scalability truly matter.

We offer:

•  the opportunity to suggest and implement your own ideas that directly influence the product and its mass production.
• A place in a fast-growing company with a motivated and professional team.
• Medical insurance.
• Corporate English classes.
• The opportunity to participate in Ajax’s internal beta-testing program for security systems.
• Discounts from partner companies and on Ajax products.

Ajax Systems is a Ukrainian success story that has grown into a global product. Ajax devices are trusted by more than 4.5 million end users and 330,000 PRO users in over 180 countries. The company provides comprehensive solutions to protect residential and commercial properties of all sizes. Today, Ajax portfolio includes 280 devices for intrusion protection, video surveillance, fire safety, and comfort and automation.