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Senior Full-Stack Engineer (React+Node.js)

Location:
Remote
Level:
Senior
English:
Project stage:
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

Team Composition:
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

Work & Life Balance

20 paid working days off
Soulful corporate events and team buildings
Opportunity to work remotely

Work Environment

All the necessary equipment
A comfortable and modern office
Accounting services
Relocation reimbursement

Health & Wellness

Health insurance
$600 extra for the health care, sports or mental health
10 working days of sick leave

Professional Development

$600/year you can spend on:
Courses, trainings, seminars
Improvement of qualification/ certification
English lessons

[ our values/ ]

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

Pragmatic

Theory’s cute, but results pay the bills. Perfect’s a fairy tale—done right is what counts.
Adult

Adult

No drama, no sugarcoating. We own our wins and our screw-ups, and treat failure like free tuition.
Craftspeople

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

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

Great Allies

No lone wolves here. We listen before we talk, communicate like grown-ups, and make the ride better for everyone.

[ 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
Lviv
Myroslava Skoryka Street, 31, Lviv, Ukraine, 79000
diana.zherebetska@mev.com
Cherkasy
Pushkina Street, 100, Cherkasy, Ukraine, 18000
vladyslava.korol@mev.com
Walnut Creek
1212 Broadway Plaza, Walnut Creek, California, USA
solutions@mev.com

FAQs

Got questions? No worries, we've got all your answers covered in our FAQ!

Absolutely! We offer flexible remote work options, so you can work from anywhere worldwide. Prefer the office vibe? We’ve got a modern, comfy workspace in Ukraine, fully equipped with everything you need.

We have a structured onboarding process to make your transition smooth and welcoming. You’ll have access to mentors, detailed resources, and a supportive team to help you hit the ground running.

We conduct performance reviews every six months to assess your achievements, align your goals with the company’s vision, and identify growth opportunities. During these reviews, you’ll:

  • Get a clear picture of your strengths and areas to improve
  • Receive feedback on your performance and productivity
  • Set goals that align with your career path and the company’s strategy

At MEV, we’re all about continuous learning and growth. Here’s what a typical path looks like for a Software Engineer:

  • Junior Engineer: Build foundational skills like bug fixing and documentation with guidance from senior team members.
  • Mid-level Engineer: Take on more complex tasks, mentor junior engineers, and play a bigger role in problem-solving and code optimization.
  • Senior Engineer: Lead projects, tackle high-level technical challenges, and align technical work with business goals. You’ll also mentor others and drive innovation within the team.
  • Staff Engineer: Lead large-scale projects, design system-wide architectures, and manage multi-team efforts. You’ll mentor senior engineers and steer the technical strategy.

At every step, your responsibilities grow—and so does your impact. Regular reviews and professional development opportunities keep you moving forward.

We believe in open, transparent communication and a collaborative culture. Regular team meetings, project updates, and social events keep everyone connected and engaged.

We’re big on balance. Here’s what we offer:

  • 20 paid vacation days per year
  • 10 sick days
  • Flexible working hours

Your well-being matters to us. We offer:

  • Comprehensive health insurance
  • $600 annually for healthcare, sports, or mental health support

We invest in your growth. You’ll get $600 annually to spend on:

  • Courses, trainings, and seminars
  • Professional certifications
  • English lessons

Our culture is built on mutual respect, continuous learning, and a passion for innovation. We value diversity, creativity, and a good sense of humor. We’re a team of professionals who support each other, celebrate successes, and challenge ourselves to grow.

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