Stefan
Cvetkovic

When Serbia introduced mandatory electronic invoicing through the state platform SEF (Sistem e-Faktura), every company in the country had to adapt overnight. For a Big4 accounting firm managing invoicing on behalf of hundreds of corporate clients, doing this manually was never an option. We built the integration that made it seamless — a fully automated pipeline that generates, validates, signs, and submits eFaktura-compliant XML documents to SEF, then reconciles responses back into the client's internal systems.

The solution runs as a .NET Core service with an async messaging backbone via RabbitMQ, giving it the throughput to handle month-end spikes without degradation. Every submission is fully auditable, with structured logs capturing the full lifecycle from generation through SEF acknowledgement.

UN Women needed a purpose-built platform to coordinate, track, and report on their awareness and empowerment programs across Serbia. The portal serves program coordinators, field workers, and UN reporting stakeholders — each with distinct data access needs, workflows, and reporting requirements. We built it end-to-end: from requirements gathering with UN representatives through to production deployment.

Built on Clean Architecture with .NET Core, the system separates program management, participant tracking, and reporting into well-defined bounded contexts. Aggregate reporting feeds directly into the format required by UN Women's international reporting obligations, removing a previously manual export and consolidation step.

Businesses live and die by their online reputation, yet responding to hundreds of customer reviews consistently and on-brand is a full-time job. Replona automates this entirely — it ingests reviews from Google, TripAdvisor, and other platforms, and generates contextually relevant, brand-voice-aware responses using Anthropic's Claude, ready to post with a single click.

The orchestration layer runs on n8n, connecting review ingestion, agent invocations, and platform posting into a visual workflow that non-technical team members can adjust without touching code. The entire development workflow — from designing agent skills to iterating on prompt chains — is itself AI-assisted, using Claude Code to accelerate implementation and catch edge cases before they reach production.

Large organizations often run parallel scheduling systems that drift out of sync — internal CRM calendars, Microsoft 365, and field team schedules accumulate conflicts that cost real time. CalendarSynchronizer is a robust .NET background service that keeps these systems continuously aligned through Microsoft Graph API delta sync, with full support for multi-tenant Azure Entra ID authentication.

Runs as a .NET 8 hosted background worker, processes delta change feeds from Graph API to avoid polling, and uses structured logging with full correlation IDs to make production debugging tractable across tenant boundaries.

Scaffold inventory on active construction sites is counted manually — a tedious, error-prone process that slows down logistics and billing. Scaffold Counter is a cross-platform Flutter app that lets site managers photograph a scaffold assembly and receive a structured, exportable count in seconds, powered by Claude Vision API.

Fully offline-capable with SQLite-backed local storage — works reliably on sites with poor connectivity. Completed counts export directly to PDF or Excel, integrating cleanly with existing site reporting without requiring any back-end infrastructure.

Consultants and digital agencies spend significant time manually auditing client websites across dozens of dimensions — performance, SEO health, accessibility, broken links, security headers, and more. RevisorIO consolidates this into a single platform: run an audit, get a prioritized report, track remediation over time, and manage multiple clients from one dashboard.

Built on Clean Architecture .NET backend with a React frontend. Supports multi-client workspaces, scheduled re-audits, and delta comparison between runs to track remediation progress over time.