Василь

Vasyl Mushchynka
Full-Stack Developer (React / Next.js / Node.js / TypeScript)

Lviv, Ukraine | [open contact info](look above in the "contact info" section) |

[open contact info](look above in the "contact info" section) | github.com/vaSIUl13

Profiessional Summary
Full-Stack Developer with commercial experience on two production products: a multi-
tenant SaaS platform and an internal CRM. Builds secure REST APIs, relational data
models and responsive React/Next.js interfaces in TypeScript and Node.js. Integrated the
Anthropic Claude API into production workflows and ships containerized services
(Docker) with CI/CD (GitHub Actions). Works in Agile teams with code review and
automated testing. Computer Science student at Lviv Polytechnic National University.

Technical Skills
Languages: TypeScript, JavaScript (ES2022+), SQL, HTML5, CSS3
Frontend: React, Next.js, Vite, Tailwind CSS, SCSS, Single-Page Applications (SPA),
Responsive Design
Backend: Node.js, NestJS, Express.js, REST API Design, OpenAPI, JWT Authentication,
Role-Based Access Control (RBAC), Multi-Tenant Architecture, Asynchronous Event
Processing
Databases: PostgreSQL, MySQL, SQLite, Prisma ORM, Firebase (Firestore, Auth, Cloud
Storage), Supabase, Database Migrations
DevOps and Testing: Docker, Docker Compose, CI/CD, GitHub Actions, Git,
SonarCloud, ESLint, Prettier, Automated Service and HTTP Tests
Integrations: Anthropic Claude API (LLM, Prompt Engineering, Structured Outputs),
Stripe, Webhooks, Email and Messaging Services
Practices: Agile, Code Review, Pull Requests, Technical Documentation

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Profiessional Experience

Full-Stack Developer, Seeda (infiluencer and brand campaign platfiorm) | 09/2026 –
Present
Designed and delivered REST APIs in Node.js and TypeScript for a multi-tenant SaaS
platform with role-based access control across agency, creator and brand portals.
Built end-to-end features for the full campaign lifecycle: applications, marketplace
discovery, opt-in/compliance, fulfilment tracking and performance analytics.
Implemented JWT authentication and middleware-based authorization with
organization/tenant context, enforcing strict data isolation between users and tenants.
Integrated third-party email, messaging and shipment-tracking APIs; introduced
asynchronous event processing with idempotent notification dispatch to prevent
duplicate sends.
Modeled relational data with migrations, validated API contracts with schemas and
OpenAPI, and maintained technical documentation for smooth frontend handoff.
Improved reliability and security through automated service and HTTP tests, rate
limiting, transactional updates and safe operational tooling for staging environments.
Delivered in an Agile ticket/pull-request workflow with code review, shipping
containerized (Docker) services on managed cloud infrastructure.

Full-Stack Developer, Insiders (internal CRM, BennuSigns) | 06/2026 – 09/2026
Built full-stack features for an internal CRM using Next.js, Node.js and TypeScript,
including responsive admin dashboards for system administrators.
Designed and maintained relational database schemas with Prisma ORM, writing
migrations and optimized SQL queries as business requirements changed.
Integrated the Anthropic Claude API using engineered system prompts and structured
outputs to automatically parse and process customer-specific requests.
Developed and documented modular REST API endpoints connecting business logic,
database transactions and third-party integrations to the frontend.
Built custom admin features and refactored API calls, improving client-server state
synchronization and reliability.

Education
Bachelor of Computer Science, Lviv Polytechnic National University | 2024 – Present

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Languages
Ukrainian (native) | English (B1–B2, intermediate)

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