Full Stack .NET Developer

Denis M

Information

Available hours \ week
40 h/w
Seniority level
Senior
Years of experience
10 yrs.
Location
Spain
Nationality
Ukraine
Timezone
(GMT+01:00) Madrid

Languages

English
Upper-Intermediate (B2)

About

Denis is a Full Stack .NET Developer with extensive expertise in ASP.NET MVC, C#, and .NET Core, accumulating 10 years of experience in software development. His proficiency spans various frameworks and cloud platforms, enabling him to deliver robust applications across multiple domains. He has developed and maintained scalable back-end services and complex REST APIs that streamline processes in industries such as Fintech, Retail, and Event Management. Denis excels at implementing microservices architectures and leveraging Azure for cloud solutions. His work includes creating efficient billing systems, order management platforms, and HR tracking solutions, where he successfully navigated challenges like database optimization and real-time event processing. Aside from core competencies, he is adept in technologies like TypeScript, Angular, and Microsoft SQL Server, enhancing his ability to create seamless user experiences. Denis holds no formal educational qualifications listed, but his considerable professional experience speaks volumes about his capabilities.

Experience

FinTech Subscription & Usage-Based Billing Portal

Back-end Developer

About the Project

A self-service billing portal where SMB customers manage plans, add-ons, seats, and payment methods in one place. It tracks metered usage (events/transactions/API calls) in near real time, converts it into billable line items, and generates invoices automatically. The system supports proration, credits, refunds, and tax-ready invoice templates, with full audit history of billing changes. Includes an internal admin console for support overrides, dispute handling, and customer account controls.

  • Fintech

Responsibilities

- Designed and implemented the backend with clean separation of concerns and reusable service layers; - Built billing flows: plan upgrades/downgrades, proration, refunds, and invoice generation; - Integrated payment processing and webhooks to keep billing state consistent; - Delivered an admin panel for customer support (manual adjustments, invoice re-send, account locks).

Order Management System for Multi-Warehouse E-commerce

Back-end Developer

About the Project

A centralized OMS that ingests orders from multiple sales channels, validates inventory, and allocates items across warehouses based on stock, location, and fulfillment rules. It orchestrates the full lifecycle from reservation to picking/packing, shipment creation, and returns, while syncing statuses with carriers and storefronts. The platform provides operational dashboards for backlog, SLA tracking, and warehouse performance with fast reporting queries. Built to handle spikes, partial shipments, cancellations, and real-world exceptions without losing data consistency.

  • Retail
  • Management

Responsibilities

- Built REST APIs for order lifecycle (create, reserve stock, pick/pack, ship, cancel/return); - Implemented stored procedures/views for high-performance reporting and operational dashboards; - Added role-based access and audit trails for critical actions; - Optimized database queries and introduced caching for high-traffic endpoints.

Skills & technologies

Real-Time Notifications & Alerts Microservice Suite

.Net Developer

About the Project

An event-driven notification platform that listens to business events (payments, job failures, SLA breaches) and delivers email/in-app alerts with consistent routing rules. It includes template management with localization, versioning, and preview/testing, plus user preferences and suppression windows to reduce noise. The system guarantees reliable delivery through retries, idempotency, and dead-letter queues for bad payloads, with traceability per event. Provides monitoring dashboards for throughput, latency, provider failures, and alert health.

  • Productivity

Responsibilities

- Implemented event contracts and handlers for multiple event types; - Built retry policies, dead-letter handling, and idempotency for event processing; - Created a notification templates module with versioning and preview tools; - Added monitoring dashboards and alerting rules for failures and latency spikes.

HR Candidate Tracking & Interview Scheduling Platform

Full-Stack .NET Developer

About the Project

An internal ATS that manages candidate profiles, pipelines, and evaluation scorecards with structured feedback and hiring approvals. It supports interview scheduling with conflict checks, team calendars, and multi-stage interview loops, including automated reminders and status updates. Recruiters can search/filter by skills, tags, and history, while managers track pipeline velocity and bottlenecks. The platform includes analytics on time-to-hire, stage conversion, and interviewer workload distribution.

  • Event Management
  • Management

Responsibilities

- Built pipeline stages, tagging, and search with advanced filters; - Implemented interview scheduling with conflict detection and team availability views; - Created analytics: time-to-hire, stage drop-off, and recruiter workload; - Delivered a responsive UI with reusable components and form validation.

Marketing Landing Builder with CMS-Style Blocks

Full-stack web developer

About the Project

A no-code landing page builder where marketing teams assemble pages from predefined content blocks (hero, pricing, FAQ, testimonials, forms). It supports drafts, approvals, scheduled publishing, rollback to previous versions, and reusable snippets for brand consistency. The system generates SEO-friendly pages with metadata controls, clean URLs, and automatic sitemap updates. Includes asset management for images/files and a preview environment to validate layouts across devices before publishing.

  • Marketing

Responsibilities

- Built a component-based editor with drag-and-drop sections and previews; - Implemented versioning (draft/publish), rollback, and page scheduling; - Created SEO tooling: metadata, sitemap generation, and friendly URLs; - Added asset management for images and reusable content snippets.

Payment Reconciliation & Payouts Automation

.Net Developer

About the Project

A back-office reconciliation system that imports transactions from payment providers and internal ledgers, then matches them to orders/invoices to detect discrepancies. It flags mismatches (missing captures, partial refunds, duplicate charges) and routes them into review queues with evidence and suggested resolutions. The platform automates vendor payouts via approval workflows, supporting holdbacks, thresholds, and scheduled payout batches. Provides export-ready accounting reports, audit logs, and operational monitoring for failed runs.

  • Fintech

Responsibilities

- Imported transactions, normalized data, and matched records across sources; - Built discrepancy detection rules and approval workflows for payouts; - Implemented export reports for accounting and compliance requirements; -Added scheduled jobs and operational monitoring for automation runs.

Multi-Tenant SaaS Admin Console

.Net Developer

About the Project

An admin console for operating a multi-tenant SaaS: managing tenants, users, roles, feature flags, configuration, and environment-level settings. It supports tenant onboarding flows, data isolation patterns, usage tracking, and per-tenant limits/quotas with consistent governance controls. Includes audit logging for privileged actions, admin impersonation (controlled), and customer support tooling for troubleshooting. Provides telemetry views for adoption, feature utilization, and operational health by tenant.

  • Management

Responsibilities

- Designed tenant isolation strategy in database schema and service layer; - Implemented feature flags and per-tenant configuration management; - Built onboarding: tenant creation, initial admin invite, and environment setup; - Added telemetry and usage analytics per tenant.