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Senior Full-Stack Engineer (React/Node.js)
Project Overview
Our client builds post-quantum cryptography solutions that help enterprises assess and manage cryptographic risk. Their flagship platform inventories cryptographic assets (certificates, keys, algorithms) across enterprise infrastructure and analyzes vulnerabilities against post-quantum threats. The platform serves the government, finance, and utilities sectors where cryptographic security is critical.
We are looking for a Senior Full-Stack Engineer to join a migration project transforming the platform from single-tenant deployments to a multi-tenant, multi-cloud architecture. You’ll work on both React frontend and Node.js backend, implementing tenant isolation, hierarchical access control, and cloud-agnostic deployment patterns. This role requires in-depth backend expertise with a secondary front-end skill, focusing on containerized microservices, database architecture, and complex data migrations.
You’ll collaborate with a solutions architect, DevOps engineer, QA team, and the client’s development team to deliver a proof-of-concept by January 2026, followed by production migration over the remaining contract period. The project starts with discovery and architecture design in early December 2025, with hands-on development ramping up through the 6-month engagement.
Technical Details:
- Frontend: React (JavaScript), Nginx
- Backend: Node.js, Express, JavaScript
- Database: PostgreSQL (relational data, users, scoring rules), Elasticsearch (cryptographic facts, analytics)
- Authentication: OIDC/SSO (integration TBD), certificate-based service authentication
- Infrastructure: Docker (containerization), Docker Compose (local dev only), AWS EC2 (current single-tenant), ECS/Fargate (production deployment, DevOps-managed), multi-cloud target architecture
- Services: SSLyze (network probe), Bootstrap CA (internal PKI), SSL/TLS throughout
- Testing: Zeuz (integration tests), unit testing framework (TBD during restoration)
- CI/CD: GitHub (existing), deployment automation (TBD)
- Observability: TBD (logging, monitoring, error tracking)
Job Highlights:
- Architect and implement multi-tenant isolation patterns across Elasticsearch and PostgreSQL
- Work on platformizing a post-quantum cryptography product for scalable deployment (no cryptography expertise required — our focus is on multi-tenant architecture and deployment automation)
- Solve complex technical challenges: tenant-aware data segregation, multi-cloud portability, zero-downtime migrations
- Modern containerized microservices architecture with Docker, Elasticsearch, and certificate-based authentication
- Multi-tenancy implementation with architectural freedom and migration strategy ownership
- Collaborate directly with client CTO and lead developer on high-impact architectural decisions
Responsibilities
- Implement multi-tenant data isolation patterns in Elasticsearch and PostgreSQL, including tenant namespace conventions and data segregation across all service layers
- Build React frontend components for hierarchical tenant management (partners, customers, users) and tenant-scoped dashboards
- Develop Node.js backend APIs with tenant-aware routing, query filtering, and data segregation enforcement
- Implement OIDC/SSO integration and role-based access control (RBAC) for multi-level tenant hierarchy
- Create data migration scripts and zero-downtime migration strategies for existing single-tenant deployments with validation and rollback capabilities
- Ensure multi-tenant queries perform efficiently in Elasticsearch and PostgreSQL without degrading existing performance
- Implement automated testing (unit and integration) for tenant isolation and data segregation scenarios
- Work with Docker to containerize applications and ensure deployment readiness for production orchestration platforms
- Collaborate with the solutions architect on technical decisions, migration planning, architecture documentation, and component-level design proposals
- Conduct code reviews, ensuring tenant isolation security, query performance, and adherence to multi-tenancy patterns
- Partner with a DevOps engineer on container orchestration and cloud-agnostic infrastructure, and with the QA team on test case definition for cross-tenant data leakage scenarios
- Participate in sprint planning, daily standups, and weekly client syncs with leadership and the development team
Qualifications
- 5+ years of full-stack development experience with React and Node.js in production environments
- Experience using AI-powered productivity tools (Cursor, VS Code with Copilot, or similar AI-enhanced IDEs) and LLMs for research and problem-solving (ChatGPT, Claude, etc.)
- Strong proficiency in React and modern JavaScript (ES6+) for building complex user interfaces
- Solid experience with Node.js and Express building REST APIs with authentication and authorization
- Deep understanding of PostgreSQL, including query optimization, indexes, migrations, and transaction management
- Hands-on experience with ElasticSearch, including index design, query DSL, aggregations, and performance tuning
- Strong knowledge of multi-tenant architecture patterns (schema isolation, row-level security, tenant namespacing)
- Experience with Docker and containerized microservices architectures in production
- Understanding of authentication patterns (OIDC, SSO, JWT, session management, RBAC)
- Experience with data migrations, including strategy design, validation, and rollback procedures
- Strong understanding of software design patterns and architectural principles for building maintainable, scalable systems
- Strong problem-solving skills and ability to work autonomously with minimal oversight
- Clear written and spoken English for async collaboration and documentation
Nice to Have
- Experience with multi-cloud deployments (AWS, Azure, GCP) and cloud-agnostic architecture patterns
- Familiarity with container orchestration platforms (ECS, EKS, Kubernetes)
- Knowledge of the Elasticsearch Painless scripting language
- Experience with cryptography concepts, PKI, certificate management, or security assessment tools
- Familiarity with certificate-based authentication and SSL/TLS security practices
- Background in migrating legacy single-tenant applications to multi-tenant SaaS architectures
- Experience with zero-downtime deployment strategies and blue-green migrations
- Familiarity with TypeScript (potential future migration from JavaScript)
- Knowledge of test automation frameworks for integration testing (experience with Zeuz is a plus)
- Understanding of post-quantum cryptography or cybersecurity domains
- Experience working with government, finance, or utilities sector security requirements
- Familiarity with partner/reseller SaaS models and hierarchical tenant structures
- Knowledge of observability tools (logging, monitoring, error tracking, APM)
- Background in architecture projects involving data model migrations
- GitHub-based workflows and conventional commits
Workflow
- Multi-tenant architecture implementation: Implement tenant isolation models for Elasticsearch (cryptographic facts) and PostgreSQL (users, scoring rules, metadata), design component-level solutions for tenant-aware queries and data segregation, and develop tenant ID propagation across all services
- Full-stack feature development: Build React frontend features for partner—customer—user hierarchy management, implement Node.js backend APIs for multi-tenant CRUD operations, and develop tenant-scoped analytics and reporting interfaces
- Authentication and access control: Integrate OIDC/SSO authentication, implement role-based access control (RBAC) for hierarchical tenancy (partners → customers → users), and build admin interfaces for user and access management
- Data migration and transformation: Plan and execute migration from single-tenant to multi-tenant data models, implement zero-downtime migration strategies with rollback capabilities, and build data validation and integrity checks
- Backend API development: Extend Node.js/Express REST APIs for tenant-aware operations and optimize query performance for multi-tenant Elasticsearch and PostgreSQL
- Containerization and deployment support: Work with Docker to containerize services (backend, frontend, Postgres, Elasticsearch, SSLyze network probe), contribute to multi-cloud deployment architecture discussions, and ensure applications are deployment-ready for container orchestration platforms
Note: The DevOps engineer will handle production infrastructure provisioning, CI/CD pipelines, and container orchestration (ECS/Fargate or similar). A solutions architect provides architecture guidance and technical leadership during the discovery phase
Our Benefits
Good projects, smart colleagues, and reasonable people are a pretty good start. Add some flexibility, room to grow, and benefits that are actually useful, and we're getting somewhere.
Time for Life
- 20 paid days off and 10 paid sick days
- Paid public holidays based on your local calendar
- Remote work
Benefits You’ll Actually Use
- Health insurance from your first working day
- A $1,000 annual flexible benefits budget per person
- Use it your way across eligible categories
The Basics, Done Properly
- All the equipment you need
- A dedicated budget for software and AI tools
- Comfortable, modern offices in Lviv and Cherkasy, with relocation support to either city
Growth Without Guesswork
- Performance reviews every six months
- Career support and clear next steps from your Line Manager
- A career path based on a competency matrix
[ why us/ ]
What Keeps Us Sharp and Steady
We cut the fluff and keep it real—owning our work, refining our craft, and always leveling up. No excuses, just a team that’s in it together, pushing boundaries and delivering results.
Pragmatic
Theory’s cute, but results pay the bills. Perfect’s a fairy tale—done right is what counts.
Adult
No drama, no sugarcoating. We own our wins and our screw-ups, and treat failure like free tuition.
Craftspeople
We’re not assembly-line coders. We build, we refine, and we don’t put a fresh coat of paint on bad code.
Forever Learners
Falling behind? We leave that to others. Leveling up fast, chasing down answers, and never settling for “I don’t know.”
Great Allies
No lone wolves here. We listen before we talk, communicate like grown-ups, and make the ride better for everyone.
Didn’t Find the Right Role?
Drop your resume, and we’ll be in touch if the right opportunity comes up.
[ global team, remote freedom/ ]
Headquartered in the USA and Ukraine, but our team? We're everywhere.
We’re fully remote, so you can work wherever you’re most productive.
Costa Rica
Team Hub
USA
Strategic & Office & Team Hub
Spain
Strategic & Team Hub
Poland
Strategic & Team Hub
Romania
Team Hub
Ukraine
Office & Team Hub
Costa Rica
Bulgaria
Team Hub
Georgia
Team Hub
Armenia
Team Hub
Frequently Asked Questions
FAQ
What benefits do you offer for work-life balance?
We’re big on balance. Here’s what we offer:
- 20 paid vacation days per year
- 10 sick days
- Paid public holidays based on your local calendar
- Flexible working hours
What health and wellness benefits are provided?
Your well-being matters to us. We offer:
- Comprehensive health insurance
- An annual $1,000 Cafeteria Benefits budget that you can allocate across eligible options based on your personal needs and priorities, including healthcare, sports, mental health support etc.
What kind of professional development opportunities are available?
We’re committed to supporting your growth and continuous learning. You can take advantage of:
- Corporate English Speaking Clubs to practice English and build confidence in a collaborative environment.
- Professional development opportunities, including courses, trainings, seminars, certifications, and English lessons, which can be covered through your Cafeteria Benefits budget.
[ apply cv/ ]
Application Form
Hiring process:
01
Apply CV
Connect with our Talent Acquisition
02
HR Interview
Join a 30-60 minute interview session
03
Technical Interview
We hold a 1.5-hour interview
04
Final Interview (as needed)
Meet with key stakeholders
Daria Formanyuk HR manager
Feel free to reach out to me at
diana.zherebetska@mev.com
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