Jobs Backend

Hey there! We're looking for an ambitious tech lead ready to own the entire 𝗔𝗜 𝗚𝗧𝗠 𝗣𝗹𝗮𝘁𝗳𝗼𝗿𝗺 - from code to deployment. No micromanagement, just real ownership. 

🔧 𝗪𝗵𝗮𝘁 𝘆𝗼𝘂'𝗹𝗹 𝗱𝗼
• Build features end-to-end: Go backend (API + background workers) and React frontend - hands-on, no split between "backend" and "frontend"
• Own the full deployment cycle: builds, systemd, nginx, Postgres migrations, rollbacks
• Integrate external services: email (Brevo, IMAP), data enrichment (Apollo, Hunter, ZoomInfo), LLMs (OpenRouter, Claude), Slack, CRM
• Build data pipelines: CSV imports, deduplication, idempotent updates
• Review PRs, merge, deploy
• Work directly with non-technical stakeholders - turn a conversation into a shipped feature

⭐ 𝗪𝗵𝗼 𝘆𝗼𝘂 𝗮𝗿𝗲
• Product-minded -you resolve ambiguity with sensible defaults, not endless spec requests
• Fast but security-conscious - mass email means one mistake can hurt domain reputation
• Autonomous - ship it, verify it, fix it, confirm it, on your own

• Production-level Go: goroutines, contexts, pgx, clean SQL (no ORM)
• React + TypeScript + Vite + Tailwind, React Query
• PostgreSQL: strong SQL, indexing, migrations
• Linux, Docker, nginx, systemd - independent deployment and ops
• Email deliverability (SPF/DKIM/DMARC), IMAP, transactional providers
• LLM integration in production
• Scraping (Playwright, anti-bot evasion)
• Solo or small early-stage team experience

🚀 𝗪𝗵𝗮𝘁 𝘄𝗲 𝗼𝗳𝗳𝗲𝗿
• Fully remote- work from anywhere in the world
• Build and shape your own team as the product grows
• Full ownership and freedom to execute your vision, no bureaucracy
• Direct, visible impact -  what you ship actually matters
 

123Cluster is a leading onsite solution provider for end-to-end database management. We specialize in Oracle, MySQL, MariaDB, MongoDB, PostgreSQL, Redis, SQL Server, and Elasticsearch. Our platform features a user-friendly drag-and-drop interface, private database cloud, and is fully DevOps-ready.

We're looking for a Developer who enjoys the infrastructure side of backend work — someone comfortable with VMs and Kubernetes, building the logic that automates database operations and shipping Helm charts to clients.

What makes you a great fit:

• 1+ years of professional software development experience with Python.
• Proficient with Django and Django REST Framework.
• Solid SQL skills — you write queries, understand joins, indexing, and can reason about query performance.
• Hands-on experience with Kubernetes: deploying workloads, debugging pods, reading and writing YAML manifests.
• Comfortable working with VMs — you know your way around a Linux environment.
• Written and spoken English at a working proficiency level.
• Self-proactive — you spot problems, propose improvements, and suggest better ways to solve things.
   

Will be a plus:

• Understanding of PostgreSQL replication: streaming replication, logical replication, failover and switchover mechanics.
• Experience with PgBouncer, HAProxy, and Keepalived for connection pooling, load balancing, and high availability.
• Prior experience writing or maintaining Helm charts.
• Exposure to additional database engines (MySQL, Oracle, SQL Server, Elasticsearch).

Your day-to-day in this position:

• Build and maintain the Django DRF API and raw Python task services for database provisioning, replication, backups, and health monitoring across VMs, Proxmox, and Kubernetes.
• Own Helm chart releases for client-facing deployments.
• Navigate VM-based and Kubernetes-hosted database instances — handle differences in networking, storage, and failover.

• Write and optimize SQL queries for API endpoints interacting with managed database instances.

   

Why work with us?

• Product company in the final pre-release stage — real impact on what ships.
• 3-month structured onboarding alongside database experts, Kubernetes engineers, and code leads.
• Fully remote, full-time position.
• Direct influence on architecture and tooling decisions.

Job Description

• Strong Python: 3+ years of professional experience in Python development
• 3 years experience in Object Oriented development 
• Proficiency with Python and common libraries (e.g., requests, asyncio, SQLAlchemy, FastAPI/Django/Flask depending on the stack)
• Passion for open source development and a community mindset
• Proficiency with Git workflows (forking, pull requests, code reviews)
• Understanding of open‑source licenses and contribution etiquette
• Understanding of Kubernetes fundamentals (pods, deployments, services, config maps, secrets) and familiarity with containerization (Docker)
• Strong SQL querying and optimization skills and familiarity with MariaDB‑specific features (e.g., storage engines, replication options)
• Background in performance optimization or distributed systems
• Knowledge of industry standard source control systems
• Proficiency in Team Foundation Server and Visual Studio is preferred
• Experience with industry standard communication protocols; REST. JSON, XML, and SOAP
• Experience with Agile software development methodologies
• Azure experience is preferred
• Good understanding of SDLC process, version control, code review, continuous integration and automated deployment tools.
• Experience working on large-scale, production-grade projects.
• Strong background with CI/CD methodology.
• B.Sc in Computer Science is an advantage.
• Advanced level of English

Job Responsibilities

• You will be part of a team responsible for building the Royalty management solution 
• Participate in all phases of managing the Application Lifecycle Management: requirements analysis, development, testing, and implementation. Participate in technical logic and design discussions
• Investigate and resolve bugs, performance issues, and security concerns
• Create, maintain, and present technical documentation to different audiences and levels
• Perform resource, technical and risk assessments
• Work with other development, architecture, and product development teams to ensure delivery of product
• Support release processes, versioning, and dependency management
• Engage constructively with contributors for clarification and/or improvements
• Assist in the timely completion of assigned development projects
• Prepare required documentation, including project plans, software program, and user documentation
• Assist in the estimation of time for development projects
• Being the main contact point for the US based client team
• Provide technical guideline to the local team
• Interview new candidates to join the team
   

We are looking for an experienced Lead/Senior .NET Engineer to join a long-term modernization initiative focused on transforming a large-scale enterprise platform from .NET Framework 4.8 to .NET 10. This is a hands-on engineering role where you'll work on modernizing backend architecture, migrating legacy components, improving code quality, and preparing the platform for cloud-native deployment on AWS. You'll collaborate with experienced engineers in an Agile environment while helping shape the future architecture of a mission-critical system.

Responsibilities: 

• Drive the migration of a large enterprise application from .NET Framework 4.8 to .NET 10.
• Modernize backend services and replace legacy Windows-specific dependencies with cross-platform solutions.
• Migrate a large Entity Framework 6 data model to EF Core 8, one bounded context at a time.
• Refactor legacy code following modern architecture principles and best engineering practices.
• Improve automated testing by introducing unit test coverage and quality gates.
• Collaborate with DevOps engineers on containerization, Docker configuration, and AWS deployment.
• Participate in architecture discussions, code reviews, technical planning, and Agile ceremonies.

Requirements:

• 5+ years of commercial experience with C#/.NET backend development.
• Strong expertise with ASP.NET, ASP.NET Core, and modern .NET.
• Proven commercial experience migrating applications from .NET Framework to .NET Core / .NET 8+.
• Strong experience with Entity Framework Core.
• Good understanding of DDD, CQRS, and layered architecture.
• Experience building containerized applications using Docker.
• Solid knowledge of xUnit, Moq, and automated testing practices.
• Experience deploying .NET applications to AWS ECS/Fargate and working with ECR.
• Experience with RabbitMQ, MassTransit, or similar messaging technologies.
• Experience with Hangfire or other background job processing frameworks.
• Strong Git workflow and experience working in Agile teams.

Nice to have:

• Experience designing and maintaining CI/CD pipelines.
• Familiarity with Angular applications or micro-frontend architecture.
• Experience implementing automated code coverage in CI.
• Knowledge of performance optimization and scalable distributed systems.

We offer*:

• Flexible working format - remote, office-based or flexible
• A competitive salary and good compensation package
• Personalized career growth
• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
• Active tech communities with regular knowledge sharing
• Education reimbursement
• Memorable anniversary presents
• Corporate events and team buildings
• Other location-specific benefits

*not applicable for freelancers

Project:

We are looking for a Senior Elixir Developer to join an Israeli AI startup building the communication infrastructure for distributed AI agents. The platform enables AI agents built with different frameworks, such as LangChain, CrewAI, Claude Code, and others, to discover each other, exchange context, delegate tasks, and collaborate securely in real time within enterprise environments.

You will be joining the team at an exciting stage, helping shape the core platform and build highly scalable backend services that power communication, coordination, and governance between AI agents. This is an opportunity to work on cutting-edge AI infrastructure rather than traditional AI applications.

Cooperation: Long-term engagement, full-time
Stage: Seed-stage startup
Position: New role
Timezone: European timezone
Location: Remote
English level: Upper-Intermediate or higher

Requirements:

• 8+ years of software engineering experience.
• Deep commercial experience with Elixir.
• Strong understanding of distributed systems and backend architecture.
• Experience designing scalable, high-performance services.
• Ability to work independently in a fast-paced startup environment.
• Strong problem-solving and communication skills.
• Upper-Intermediate English or higher.

Responsibilities:

• Design, develop, and maintain scalable backend services using Elixir.
• Build reliable distributed systems that enable communication and coordination between AI agents.
• Develop high-performance APIs and internal platform services.
• Contribute to the architecture and evolution of the core infrastructure.
• Collaborate closely with the founding engineering team on technical decisions.
• Write clean, maintainable, and well-tested code.
• Improve system reliability, scalability, and performance.
• Participate in code reviews and help maintain engineering best practices.

​​​​​​​ Nice to Have:

• Experience building distributed or event-driven systems.
• Interest or experience in AI infrastructure, LLMs, or agent-based systems.
• Experience working in early-stage startups.
• Familiarity with enterprise-scale backend platforms.

Benefits from 8allocate:

• Team & Culture: Team events, offsites, and a culture that keeps people connected.
• Learning & Development: Budget for courses, certifications, and conferences.
• Wellbeing: Flexible support in line with company policy, with options to support your physical and mental wellbeing (sport, mental health, or medical insurance).
• Rest & Recovery: Paid vacation and sick leave.

Ajax Systems is a full-cycle company, working from idea generation and R&D to mass production and sales. We do everything: we produce physical devices (the system includes many different sensors and hubs), write firmware for them, develop the server part, and release mobile and desktop applications.

PRO Desktop meets the needs of every professional working with Ajax security systems. Facilities profiling and remote configuration, alarm monitoring and photo verification, staff administering, and a detailed event log — all in one, intuitive interface.

Responsibilities:

— Ajax PRO Desktop development (adding new devices, supporting existing devices, adding new functionality and features, fixing bugs).

— Architectural decisions and concept development.

— Writing tests.

— Hard bug fixing.

— Inter-commands communications.

Stack:

— Python 3, PySide 6, QML, gRPC.

Must have:

— 3+ years of experience with Python, including multithreading, asyncio.

— Knowledge of OOP principles and patterns.

— Experience with aiohttp.

— Experience with pytest.

— Experience with gRPC.

It will be a plus:

— Experience with QML.

— Experience with PySide/PyQt.

We offer:

— Flexible schedule at our offices in Kyiv or Lviv.

— The opportunity to propose and implement own ideas that have an impact on the product and production.

— Work in a motivated team and zero bullshit culture.

— Competitive salary.

— Medical Insurance.

— Corporate English.

— The opportunity to participate in the beta test project of Ajax security systems — receiving and testing new gadgets before their release.

About the Role

We are seeking a skilled Energy System Analyst / Software Developer to join our team and contribute to the full lifecycle of energy system modelling and simulation projects. You will focus primarily on market modelling of European energy markets, power system optimization, capacity expansion planning, cost-benefit analysis, and economic assessment of infrastructure investments, while also engaging in data handling, visualization, and automation development.

This role combines technical expertise in energy market fundamentals, analytical thinking, and software development skills to deliver high-quality modelling results and insights for our clients across the European energy sector, including TSOs, regional coordination bodies, and European institutions.

Key Responsibilities

• Lead and participate in the design, implementation, testing, and analysis of energy market models using tools such as Antares Simulator (including Antares Xpansion for capacity expansion studies).
• Develop and maintain data management, automation, and market modelling pipelines to support large-scale European energy system studies (e.g., TYNDP, IoSN, regional adequacy assessments).
• Conduct economic evaluations, cost-benefit analyses, and scenario-based simulations to support infrastructure investment decisions and cross-border interconnector assessments.
• Prepare and maintain input datasets for market models, including demand profiles, generation portfolios, fuel prices, renewable time series, and transmission capacities.
• Collaborate with client teams (TSOs, regional groups, European bodies) to ensure accuracy and consistency in data collection, validation, and central dataset maintenance.
• Communicate modelling results, methodologies, and assumptions clearly to both technical and non-technical stakeholders through reports, presentations, and steering group meetings.
• Contribute to technical documentation, methodology descriptions, and quality assurance of project deliverables.

Required Qualifications & Experience

• 2–7 years of relevant professional experience in energy system modelling, market analysis, or power system planning.
• 2+ years of proven experience in market modelling and economic analysis of energy systems.
• Proficiency in Python for modelling, simulation, data processing, and automation.
• Solid understanding of European energy market fundamentals: merit order dispatch, zonal pricing, cross-border exchanges, adequacy assessment, and capacity mechanisms.
• Strong skills in data handling, processing, and visualization of large-scale energy datasets.
• English language proficiency at B2 level or higher.
• MSc degree in Electrical Engineering, Power Engineering, Energy Economics, Computer Science, or related field.

Desirable Skills & Assets

• Experience with PLEXOS for energy market modelling, production cost simulation, or capacity expansion planning.
• Knowledge of open-source energy modelling tools such as PyPSA, Calliope, or OSeMOSYS, and the ability to benchmark or cross-validate results across platforms.
• Familiarity with Antares Simulator and Antares Xpansion for adequacy studies and optimal investment modelling.
• Knowledge of optimization theory and mathematical programming (LP, MILP) as applied to energy system planning.
• Understanding of European regulatory frameworks: ENTSO-E methodologies (TYNDP, ERAA, IoSN), CBAM, EU Green Deal targets, and network development processes.
• Proficiency in R for statistical analysis or simulation post-processing.
• Familiarity with Git or other version control systems.
• Ability to translate customer requirements into actionable modelling tasks and deliverables.
• Experience in applying AI tools to support programming and analytical work.
• Strong communication and teamwork skills, with the ability to meet deadlines and work effectively in multi-stakeholder project environments.

We are looking for a Full Stack Engineer to join our team at ORIL. This is an opportunity to work on a sophisticated PropTech / MarTech platform that is currently reshaping how the real estate industry handles data. If you enjoy a high-tempo environment, love working with AI, and want to see your code make a direct impact on business decisions, this is for you.
 

About the Project

Our client is a US-based innovator providing a centralized data platform for multi-family real estate. The product uses BI and AI analytics to help operators optimize marketing spend and operational efficiency.
 

Tech Stack: Ruby on Rails, React, PostgreSQL, AI/LLM integrations, AWS.
 

What are we looking for?

• 3+ years of experience in Full Stack development using Ruby on Rails and React;
• Proactive Delivery: You are comfortable with a fast development pace. You don’t wait for detailed instructions on every edge case—you think ahead and deliver ready-to-use features;
• Technical Independence: You can take a high-level requirement and turn it into a working feature (from DB schema to UI) without constant supervision;
• Problem-Solving: You focus on making things work efficiently and aren’t afraid to dig into complex data or scraping logic;
• Communication: Ability to discuss technical solutions directly with the team and the client;
• English level: Upper-Intermediate (B2).
   

Nice to have:

• Experience in PropTech or fast-growing SaaS startups;
• Experience with web scraping or complex data ingestion;
• Familiarity with AI/LLM integrations (OpenAI API, etc.).
   

What will you do?

• Develop and maintain features across the full stack (RoR + React);
• Build and optimize integrations with external property management and marketing tools;
• Work on the AI assistant’s backend logic and its UI representation;
• Help the team maintain a high tempo while keeping the code clean and scalable;
• Collaborate with the Lead dev and PM to refine the technical roadmap.
   

We offer:

• Competitive compensation;
• Flexibility to work from anywhere (fully remotely or in our office in Lviv);
• Accounting Support Services;
• Education budget + corporate education events/trainings;
• Compensation for certifications, fitness, or therapy sessions;
• A dynamic environment where your proactivity is recognized and rewarded.
   

Application Process:

1. Initial Screening: Call with Recruiter.
2. Technical Interview.
3. Client Interview.
    

Ready to build the future of Real Estate AI? Apply now and let’s get to work!

We are seeking a Senior Software Engineer / TL with strong Java backend development experience, deep database knowledge, and hands-on experience building modern cloud-based applications.
This role is focused on new product development, backend  architecture, database performance, containerized deployments, and reliable cloud-native software engineering. The ideal candidate is a strong individual contributor with excellent analytical skills, practical experience with enterprise-grade backend systems, and the ability to work independently in a fast-moving startup environment. This person should be comfortable designing, building, testing, optimizing, and deploying backend services that are reliable, secure, scalable, and maintainable. A strong ability to use modern AI tools effectively in everyday engineering work is required.
 

Key Responsibilities
- Design, develop, test, and maintain backend software using Java.
- Build reliable and scalable backend services for a database optimization platform.
- Participate in new product development, including architecture, implementation, performance tuning, and deployment.
- Design and implement REST APIs, service-layer components, data access layers, and integration points.
- Work with relational databases, especially PostgreSQL, with a strong focus on performance, query optimization, schema design, indexing, and troubleshooting.
- Analyze execution plans, identify database bottlenecks, and recommend or implement corrective actions.
- Develop containerized applications and deployment-ready services.
- Participate in cloud-native application development and deployment, especially in Azure-based environments.
- Support and improve CI/CD pipelines, automated testing practices, deployment processes, and release reliability.
- Apply secure coding practices and follow cloud security principles.
- Perform root-cause analysis for complex technical problems across application, database, operating system, and cloud layers.

- Write clean, maintainable, well-documented code.
- Participate in code reviews and contribute to engineering standards.
- Mentor less experienced engineers when needed.
- Use AI tools effectively and responsibly for coding, debugging, analysis, documentation, test generation, and technical research.
 

Required Qualifications
- 5+ years of professional Java development experience.
- Strong experience with backend application development.
- Strong understanding of the Java ecosystem, including Spring Framework / Spring Boot, REST API development, JPA / Hibernate, JDBC and database integration, multithreading and concurrency, and Java performance tuning and memory management.
- 3+ years of experience with Azure cloud environments.
- Hands-on experience with both Windows and Linux operating systems.
- Strong PostgreSQL experience, including SQL development, query optimization, schema design, indexing strategies, execution plan analysis, performance troubleshooting, and data migration
concepts.
- Strong experience with modern cloud DevOps practices, including CI/CD, cloud deployment models, release automation, environment configuration, and deployment troubleshooting.
- Strong experience with containers, especially Docker.
- Strong understanding of software architecture and design, including scalable and maintainable system design, distributed systems concepts, service-oriented or microservices architecture,
technical tradeoff analysis, and legacy modernization.
- Strong testing and code quality practices, including unit testing, integration testing, test automation, code reviews, debugging, and root-cause analysis.
- Strong analytical and problem-solving skills.
- Ability to work independently and take ownership of complex technical problems.
- Strong communication skills and ability to clarify requirements, explain tradeoffs, and propose practical solutions.
- Demonstrated ability to use AI tools productively and responsibly in daily engineering work.
 

Highly Desired / Big Plus

- Experience with MS SQL Server.
- Experience with other database platforms.
- Experience with Infrastructure as Code tools such as Terraform, Bicep, ARM templates, Pulumi, or similar.
- Experience with observability tools and practices, including logging, metrics, tracing, monitoring, alerting, and application performance diagnostics.
- Deeper understanding of cloud security operations, including identity and access management, secrets management, role-based access control, secure network configuration, and secure
deployment practices.
- Experience with Kubernetes or other container orchestration platforms.
- Experience with enterprise-grade, data-intensive applications.
- Experience working in startup-style or fast-moving product development environments.

- Good English communication skills.
 

AI Tooling Expectations
The successful candidate should be able to use AI tools as a regular part of their engineering workflow. This includes using AI to:
- Accelerate coding and refactoring.
- Generate and improve unit and integration tests.
- Assist with debugging and root-cause analysis.
- Analyze logs, errors, SQL queries, and execution plans.
- Draft technical documentation.
- Research technical approaches and compare implementation options.
- Improve productivity without compromising code quality, security, or correctness.
The candidate must understand that AI-generated output requires careful review, validation, testing, and security awareness.
 

Ideal Candidate Profile
The ideal candidate is a senior-level backend engineer who combines strong Java development skills with practical cloud, DevOps, database, and performance engineering experience.
This person should be comfortable working across application code, database design, deployment pipelines, containers, and production troubleshooting. They should be analytical, self-directed,
technically mature, and capable of making sound engineering decisions without requiring heavy supervision.
Because we are building a state-of-the-art database optimization platform, the strongest candidates will be those who enjoy technically challenging work, understand performance-oriented
engineering, and are comfortable working in a startup environment where ownership, initiative, and practical problem-solving are highly valued.

Project Description:

A next-generation cross-asset data management platform to provide globally consistent data and innovative tools to support business strategy for trade/sales clients, which is built on big data architecture, highly scalable, and cloud-ready. The platform enables industry-leading analytics, client reporting, regulatory compliance, surveillance, supervisory reporting, and data science solutions (data flame). The project tech stack: Java, Scala, Spring, SQL, Kafka, Hadoop.

We are looking for a strong Senior Java Developer capable of being able to work within the team, being a mentor for team members, communicating with stakeholders, and being accountable for the outcomes of activities that are assigned.

The role of the involves working with strong development teams (2 Senior Java Developers), the opportunity to work with big data, improving knowledge in this domain, and utilizing the resources of an international bank.

Responsibilities:

• Design and build frameworks for ingesting/modeling the complex Risk data
• Develop Low latency caching to service Front office risk systems
• Setup monitoring and management for services
• Provide SME support for development of automated QA scripts

Mandatory Skills Description:

• Strong knowledge of Big Data technologies: Hadoop Ecosystem (HDFS, Impala, HIVE, HBASE, etc.) and Apache Spark. Green flags: Spark, Hive, Hadoop.
• At least 5 years of experience in software development, including professional backend software development experience;
• Strong Knowledge of Java programming languages
• Should be familiar with algorithms and design patterns
• Familiarity with Linux environment, including scripting skills
• Designing and building APIs (Java);
• Java Server-side or Back-end development;
• Core Java;
• Java collections and multithreading;
• Java Memory Management;
• Database and SQL (writing stored procedures, designing table schemas).
• Understanding of distributed systems.
• Understanding of CI/CD workflow.

• Ability to multi-task and work under pressure.
• Ability to pick up new concepts and apply the knowledge.
• Demonstrated problem-solving skills.
• Enthusiastic and proactive approach with a willingness to learn.
• The candidate is expected to be dynamic and flexible with a high energy level as this is a demanding and rapidly changing environment

Nice-to-Have Skills Description:

• Experience In-memory databases and caching
• Job Orchestration tools like Autosys or Airflow
• Apache Spark
• Financial background (where possible)

About the Role

Are you a seasoned technical leader who loves mentoring engineers just as much as writing clean, scalable code? We are looking for an Engineering Team Lead (NODE.JS) to guide a talented backend team, drive architectural decisions, and champion engineering excellence. In this role, you will perfectly balance hands-on development with impactful people leadership to scale high-performing systems.

About the Client

Our partner is a dynamic tech company building cutting-edge product engineering across Fintech, iGaming, and Marketing. They specialize in turning innovative ideas into high-performing engines and launching them at absolute scale. As their exclusive recruitment partner, Lionhires manages their full-cycle talent acquisition, connecting top-tier tech talent with this rapidly growing team.

What You Will Do

• Lead and Mentor: Guide and develop a team of backend engineers through regular 1:1s, constructive feedback, performance evaluations, and tailored individual growth plans.
• Stay Hands-On: Directly contribute to the codebase by writing, reviewing, and refactoring high-quality code to continuously improve system performance.
• Drive Delivery & Architecture: Balance team workloads, assign tasks, design technical solutions, and make critical architectural decisions for system enhancements.
• Champion Agile: Lead and participate in agile ceremonies (Scrum/Kanban) to keep the team aligned, focused, and executing at a high velocity.
• Tackle Technical Debt: Enhance overall system quality by optimizing data flows, resolving technical debt, and performing necessary data restructuring.
• Collaborate & Innovate: Partner closely with Engineering Managers to adopt modern technologies and drive impactful, company-wide engineering initiatives.

• Elevate Standards: Document domain knowledge, refine engineering standards, and contribute to the continuous improvement of the broader engineering organization.

   

What You Bring

• Educational Foundation: A Bachelor’s or Master’s degree in Computer Science, Computer Engineering, Applied Mathematics, or a related technical field.
• Proven Experience: 8+ years of professional backend development experience, with at least 3+ years specifically in a leadership or management role.
• Core Tech Stack: Deep expertise in Node.js, modern web development, and a strong understanding of data structures, coding patterns, and algorithms.
• System Design & Infrastructure: Solid knowledge of Kubernetes, containerization, system design, SQL, and NoSQL databases.
• Integration & Security: Strong experience handling RESTful APIs, message brokers, third-party integrations, and secure development practices.
• Bonus Points: Familiarity with CI/CD pipelines, microservices architecture, cloud-based development, and Test-Driven Development (TDD).
• Soft Skills: Exceptional problem-solving and diagnostic skills, paired with a natural ability to organize, mentor, and inspire a team.

• Language: Upper-intermediate to Advanced English proficiency.

   

What's in It for You

• Growth: Ample learning and development opportunities driven by complex, highly challenging technical tasks.
• Relocation Support: A comprehensive relocation package, including covered flight tickets and a 2-week hotel stay to help you settle in.
• Work-Life Balance: 23 working days of annual vacation to ensure you have plenty of time to rest and recharge.
• Wellness & Perks: An on-site company fitness corner to stay active, plus personalized birthday celebration gifts.
• Language Development: Partial compensation for language classes to help you expand your linguistic and communication skills.

About the Role

Are you a Senior Backend Engineer who thrives on building high-performance architectures and scaling complex systems from scratch? We are looking for a Node.js/Nest.js expert to spearhead the development of our core, in-house platform, driving innovation across high-load environments. If you want to own your code, work with cutting-edge microservices, and make a tangible impact on a rapidly growing ecosystem, this is your next big move.

About the Client

Our partner is a tech company building product engineering across Fintech, iGaming, and Marketing. They turn innovative ideas into high-performing engines and launch them at scale. As their exclusive recruitment partner, Lionhires manages their full-cycle talent acquisition.

What You Will Do

• Architect and develop the core in-house platform, taking new, high-impact features from initial concept to production scale.
• Design and implement robust microservices and build seamless integrations with various third-party APIs.
• Optimize database performance for high-load systems, working extensively with both SQL and NoSQL solutions.
• Champion code quality by applying TDD (Test-Driven Development) principles and writing comprehensive automated tests.

• Collaborate cross-functionally to ensure scalability, reliability, and high availability across all backend services.

   

What You Bring

• Deep Backend Expertise: 5+ years of commercial web development experience, with a heavy focus on Node.js and Nest.js.
• Modern JavaScript Proficiency: Strong mastery of modern JavaScript and ECMAScript 6+ standards (TypeScript is a major plus).
• High-Load Database Management: Proven experience handling high-load database environments, specifically using MongoDB and MySQL.
• Advanced Communication Protocols: Practical experience implementing RESTful APIs, GraphQL, and WebSockets.
• Message Brokers & Caching: Hands-on experience working with RabbitMQ and Redis (experience with Nats is a plus).
• Architectural Mastery: Solid understanding of microservice architecture and version control via Git.
• Quality & Testing Mindset: Strong grasp of TDD principles and a habit of writing clean, testable code.

• Language Skills: Professional working proficiency in English (Intermediate level or higher).

   

Nice-to-Haves:

• 2+ years of hands-on experience working with CI/CD pipelines, containerization, and microservices.

• Direct experience with Kubernetes.

   

What's in It for You

• Financial Growth: Highly competitive salary with structured annual compensation reviews.
• Full Relocation Support: A complete relocation package including covered flight tickets and a 2-week hotel stay upon arrival.
• Legal Peace of Mind: Official EU/Spain employment contract, including registration and support for your family members.
• Work-Life Balance: 23 working days of paid annual vacation to ensure you rest and recharge properly.
• Professional Development: Continuous learning opportunities, challenging tasks, and language development support with partial class compensation.
• Culture & Community: Vibrant team-building activities, custom birthday gifts, and access to our upcoming Social Club featuring over 50 events per year.

We are looking for a Senior Go Engineer with a passion for building robust, high-performance backend systems. In this role, you will be responsible for designing and implementing scalable microservices, ensuring system reliability through optimized concurrency patterns, and maintaining high-quality code standards. You will focus on developing low-latency API responses, managing efficient data handling, and collaborating with cross-functional teams to deliver production-grade infrastructure.

About the Client

Our customer is an innovation-driven organization that provides an end-to-end, cloud-first software platform for the ready-mix concrete industry. Their solution streamlines and optimizes critical operations - from quoting, batching, and dispatch to delivery and invoicing - enabling real-time management of production and business processes. Leveraging Google Cloud and AI-driven insights, they are transforming complex logistical and data challenges into scalable, production-grade tools that improve operational efficiency, reduce waste, and enhance satisfaction across plant operators, dispatchers, and sales teams.

Responsibilities

• Backend Development: Design and implement high-performance microservices using Go and the Gorilla Mux router, focusing on clean code, concurrency, and low-latency API responses.
• Stakeholder Collaboration: Act as a proactive team player by engaging directly with stakeholders and product teams to discuss, define, and translate complex business requirements into high-quality technical solutions.
• CI/CD & Quality: Utilize an understanding of CI/CD pipelines and DevOps best practices to contribute to reliable deployment cycles and high code quality.
• API & Web Integration: Develop and maintain efficient APIs and web integrations that ensure seamless communication between backend services, frontend applications, and third-party providers.
• Third-Party Integration: Manage integrations with third-party providers, ensuring robust, scalable, and secure connectivity between external services and our core platform.

Qualifications

• Experience: 5+ years in software engineering, with at least 3+ years of professional experience building and scaling applications in Go.
• Backend Fundamentals: Solid experience with Go frameworks like Gorilla Mux and working with relational databases such as PostgreSQL.
• Development Lifecycle: Experience with CI/CD tools, containerization (Docker), and writing comprehensive unit and integration tests.

Would be a plus:

• Cloud Expertise: Proficiency in Google Cloud Platform (GCP), with specific experience in Cloud Run and infrastructure management.
• Frontend Proficiency: Experience with React and React Query to understand and support full-stack integration.
• Industry Experience: Background in logistics, delivery, or complex resource management systems.
• Messaging: Experience with Google Pub/Sub for building event-driven architectures.
• Frontend Basics: Familiarity with React to better understand how backend AI responses are consumed by the UI.

Project Description:

One of the world's largest providers of products and services to the energy industry has a need to develop and support enterprise information system in Oil & Gas domain.
Product being developed is a cloud solution for interpretation of geological and geophysical data. Project is based on SCRUM methodology.
Our project is stable, long-term and constantly adopts new technologies such as newest Java and Eclipse RCP versions, cloud and GPU computing, microservices architecture and other innovative frameworks.
Work supposes close cooperation with Customer team located in Houston and following Agile principles.
Our team is senior, supportive and friendly.

Responsibilities:

• Collaborate closely with geophysicists, data scientists, and software engineers to translate scientific domain requirements into robust on-prem or Cloud software
solutions.
• Design, develop, and maintain high-performance applications for geophysical and geological data analysis, interpretation and visualization (e.g., seismic, horizon,
fault, velocity model, etc.)
• Present architectural designs and technical proposals to the architecture review board.
• Ability to break down development tasks and lay out clear implementation roadmaps.
• Implement and optimize computation algorithms
• Design and develop both thin and thick client applications that interact with cloud-based microservices.
• Ensure high code quality through unit testing, code reviews, security hardening and continuous integration with other domain tools
• Provide technical support and lead user troubleshooting sessions to resolve issues and ensure smooth operation of DSG application.
• Mentor junior developers and actively contribute to architectural and implementation decisions.
• Embrace Agile/Scrum methodologies, delivering and demonstrating working solutions at the end of each sprint
• Stay current with emerging technologies and trends in geophysical computing and software development.

Mandatory Skills Description:

6+ years of hands-on Java development experience
Strong Java Core knowledge
Experience with desktop development frameworks: Swing, SWT, or Eclipse RCP
Proven experience designing and building complex systems end-to-end, not just maintaining or extending existing ones
Practical understanding of multithreaded programming: ability to implement concurrency in code directly, not only through third-party libraries
Solid knowledge of design patterns and software architecture principles
Ability to clearly articulate past projects, personal responsibilities, and concrete individual contributions
Experience working in non-microservices, non-cloud-native development environments (desktop, embedded, or domain-specific platforms)
Stable career trajectory, no fragmented job history with short tenures

Nice-to-Have Skills Description:

C++ development skills
Practical experience with the Eclipse RCP framework
OSGi knowledge
Oil & Gas domain experience

Languages:

English: B2 Upper Intermediate

We are looking for a Lead Backend Developer to architect and own the backend infrastructure of our fintech platform. You will design scalable microservices, manage critical data flows, and ensure system reliability at scale. Work directly with product, design, and business stakeholders to translate requirements into robust backend systems. 

This is a hybrid role, and we are currently considering candidates based in Lviv (Ukraine). 

Fully remote work is not an option for this position.

What You Will Do
Backend Architecture & Design

• Own the backend architecture end-to-end across microservices.
• Design and implement Node.js / Express services handling 20M+ transactions monthly.
• Architect PostgreSQL schemas for reliability and performance at scale.
• Define API contracts (GraphQL, REST) that support frontend and partner integrations.
• Make critical decisions on data consistency, caching, and async patterns.

Microservices & System Design

• Build and maintain multiple Node.js / Express microservices with clear ownership boundaries.
• Implement webhook-driven workflows and event-driven architecture.
• Design and implement real-time data synchronization pipelines.
• Manage message queues (RabbitMQ) for async operations and inter-service communication.
• Ensure row-level security (RLS) and multi-tenant data isolation at the database layer.

Data & Performance

• Design and optimize PostgreSQL schemas using Prisma ORM.
• Write complex queries, manage indexes, and ensure query performance.
• Implement caching strategies and data consistency patterns.
• Build audit trails and changelog tracking for compliance and debugging.
• Handle sensitive data (KYC, AML, financial records) with security-first approach.

Integration & Third-Party Services

• Integrate with external services (KYC providers, document verification, acquiring networks).
• Design and maintain API integrations with payment processors and clearing centers.
• Build robust error handling and retry logic for critical integrations.
• Document APIs and maintain SDK/integration guides for partners.
Communication & Leadership

• Work directly with product managers and stakeholders to clarify backend requirements.
• Proactively flag technical risks, propose solutions, and keep stakeholders informed.
• Give technical feedback on product feasibility and scalability implications.
• Lead backend code reviews with focus on quality, performance, and knowledge sharing.
• Mentor junior developers and foster backend engineering best practices.

What We Are Looking For
Core Requirements:

• 5–7 years of production experience in Node.js backend development.
• Strong TypeScript across the entire stack (no JavaScript-only experience).
• PostgreSQL expertise: schema design, optimization, transactions, advanced queries.
• Prisma ORM or similar ORMs and hands-on experience with relational databases.
• GraphQL schema design and resolver implementation (REST a plus).
• Microservices architecture: designing boundaries, managing state, async communication.
• RabbitMQ or similar message brokers; event-driven architecture patterns.
• Experience with fintech, payments, or regulated financial products.
• Strong communication skills and comfort working directly with non-technical stakeholders.

Nice to Have:

• Distributed systems experience (eventual consistency, saga patterns, consensus).
• gRPC for service-to-service communication.
• Experience scaling to 100K+ users and handling high transaction volume.
• Background in AML/KYC compliance or financial data handling.
• DevOps sensibility: monitoring, logging, deployment pipelines.
• Experience mentoring backend teams.

Tech Stack
Core: Node.js, Express, TypeScript, PostgreSQL, Prisma ORM, GraphQL, RabbitMQ, gRPC
Supporting: REST APIs, Webhooks, Real-time data sync, Multi-tenant architecture, Audit logging

What We Offer

• Full backend ownership and architectural control.
• Work on systems handling millions of transactions and 100K+ merchants.
• Direct access to product and business stakeholders.
• Modern microservices stack with no legacy debt.
• AI-friendly engineering culture—we embrace tools that make you more effective.
• Deep fintech learning: multi-partner networks, compliance, payment flows.
• Competitive compensation and benefits package.