Stewart Celani
Project Engineer and Developer
Passionate about user privacy. Oddly fascinated by file converters.
Often code from a treadmill.
About Me
MCSE-certified Systems Administrator turned Software Developer with 15+ years bridging enterprise IT and modern development. As a Project Engineer, I help manage infrastructure for 500+ employees by day while building production software that solves real business problems and pain points. My unique position allows me to identify inefficiencies and create integrations that drive real efficiency gains - from unifying disparate ERP systems into a single interface to automating warehouse operations with barcode scanners. Currently exploring the intersection of Rust, WebAssembly, and enterprise .NET while maintaining a steadfast commitment to user privacy. Whether it's replacing a $6k/year backup solution, breaking down data silos between departments, or building privacy-focused file converters like convert.fast - I just love to build cool things with pretty obsessive attention to detail.
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Languages & Frameworks
Specialized Skills
Currently Working On
Tools.FAST — A network of single-purpose utilities. Convert.FAST (118+ converters), Compress.FAST (TinyPNG-style bulk compression). One login, shared credits, EU servers, privacy-first.
Featured Projects
Convert.FAST
Flagship converter in the Tools.FAST network with 118+ conversion pipelines for images, RAW photos, documents, audio, and video. Vue 3 frontend uses zero-repaint hydration—mounting a complex real-time UI over static HTML for instant perceived load. Powered by a mix of the best open source and commercial libraries. Features tiered fair scheduling, real-time SSE progress updates, and ZIP downloads for batch conversions. Privacy-focused: no ads, no tracking, files auto-deleted after processing.
Compress.FAST
Bulk file compressor in the Tools.FAST network with TinyPNG-style smart compression for JPG, PNG, PDF, Word, and PowerPoint. Drop 40+ image formats (including RAW camera files) and they auto-convert to optimized JPG/PNG. Per-file before/after slider lets you visually verify quality is preserved on every file. Optional resize (4K, 1080p, 720p) for maximum compression. Handles up to 1,000 files per batch with sub-second processing. Privacy-focused: EU servers, files auto-deleted after processing.
Tools.FAST
Multi-tenant SaaS platform powering a constellation of single-purpose utilities. Consolidated identity provider built on ASP.NET Identity and OpenIddict handles OAuth2/OIDC authentication across all tools. Features multi-seat organizations with member invitations and role-based access, unified credit wallet with event-sourced ledger, entitlements API, fair job scheduling with weighted round-robin, and real-time SSE updates via Redis pub/sub. One login, shared credits, team management—consistent experience across all .fast tools.
beamit.to
Zero-knowledge file transfer service—like WeTransfer but truly private and completely free. Send up to 20GB with client-side AES-256-GCM encryption via Web Crypto API before upload. Files stream directly to Cloudflare R2 edge storage at line speed. We never see your files, filenames, or content—only encrypted blobs that auto-delete after 72 hours. High-entropy share keys with sci-fi word pairing for secure distribution. Privacy by design: if we're hacked or subpoenaed, there's nothing to give.
GitGen
Started this after hitting GitHub Desktop's auto-generate commit message paywall - thought it would be cool to build a tool that could use any AI model, including offline ones, to generate commit messages. What began as a simple alternative evolved into a full-featured CLI tool that respects your choice of AI provider. Cross-platform AI-powered Git commit message generator supporting multiple models (OpenAI, Anthropic, Google, Groq, local). Features instant model switching via aliases (@fast, @smart), secure encrypted API key storage, cost tracking, and automatic provider parameter detection. Built with .NET 9.0 as a single executable with no dependencies.
Multi-Agent Enterprise AI Chat System
Production multi-agent conversational AI system built on CQRS architecture implementing Anthropic's latest research patterns from their Building Effective Agents, Multi-Agent Research System, and Contextual Retrieval articles. Features 10+ specialized agents including Web Research Agent (Brave Search API + custom Playwright scraper), SharePoint Research, Planning, Evaluation, Synthesis, Citation, and Org Chart agents orchestrated for complex queries. Multi-provider AI architecture supports Azure OpenAI, Google Vertex AI, and custom REST endpoints. Advanced RAG system ingests SharePoint documents with contextual chunking while Web Research Agent provides real-time internet access with domain filtering and intelligent content extraction. Unique whimsical thinking traces engage users during processing ("Spelunking through documents", "Orchestrating insights"). Dual database architecture (PostgreSQL with pgvector for embeddings + MS SQL Server) powers conversation sharing with expiration controls, message ratings, and real-time PowerBI dashboards with token-level observability tracking usage per user/message/agent/workflow across all providers.
Enterprise Integration Hub App
Unified internal web application that sits on top of multiple disparate systems (ABM ERP, AutoCAD, Strumis, PowerBI) consolidating all company data into one accessible React/TypeScript interface, enabling self-service information for users like workshop supervisors who otherwise couldn't access these systems. Drives a sophisticated Bill of Materials system with live links between AutoCAD drawings and the ERP - when drawings complete approval workflows, procurement can bulk order directly into the ERP system, then fulfill via my custom warehouse picking app. Replaces legacy Access databases while providing enhanced functionality including multi-location inventory tracking, procurement automation, and comprehensive digital forms. Built with feature-based architecture using TanStack Router, React Query for server state, and SignalR for real-time updates. Features the AI Assistant frontend connecting to the Multi-Agent AI backend, with MSAL authentication providing role-based access control for 200+ users across all departments.
Android Warehouse Management App
Enterprise Android warehouse management system with integrated barcode scanner support, built for handheld devices with a sophisticated hybrid offline/online architecture. Handles complete warehouse operations including inventory control, pick order fulfillment, stock transfers, and purchase order receiving. Built with Kotlin and Jetpack Compose following Clean Architecture/MVVM patterns with reactive flows throughout. Features Room DB with SQLite WAL mode for performance, gRPC for blazing-fast syncs of hundreds of thousands of ERP rows enabling true offline-first operation while maintaining real-time responsiveness when connected to the network. Microsoft SSO integration with intelligent sync strategies that adapt to network conditions. Optimized for 2GB RAM devices with intelligent batch processing and memory management. Connects seamlessly with the Integration Hub's BOM system - when drawings are approved and orders placed, warehouse staff use this app to pick and fulfill orders, completing the entire workflow from design to delivery.
ConvertX.to
Clean Architecture .NET 8 file conversion service supporting 90+ formats via Microsoft Graph API. Built as a learning project after completing courses on design patterns, SOLID, and testing. Features automatic converter discovery via reflection, multi-page document splitting (PDFs to individual JPGs), and comprehensive testing with 82% coverage (191 unit + 220 integration tests). Includes RESTful API, Console CLI, and Blazor Web UI.
ACCBackup
Enterprise backup solution for Autodesk Construction Cloud/BIM360 in production since May 2022. Replaces a $6k AUD/year commercial solution while being 5x faster. Currently running nightly backups of 170+ projects (225GB) in 8 hours. Built with clean architecture featuring a reusable ApiClient library, fluent API design, parallel downloading with configurable concurrency, and comprehensive retry policies with exponential backoff. OAuth 2.0 two-legged authentication.
Oversight - Real-time Classroom Monitoring
Started when I saw an industry leader charging $3k for 200 Chromebooks with mediocre software. Thought "how hard could it be to get a live updating list of tabs and a screenshot from the Chromebook into a browser?" Built it during school holidays, grew to 2K AUD MRR through word of mouth alone - teachers loved it. Also had Windows version working (C# and .NET) in a test pilot school but focused on ChromeOS first. Python handled auto updating and deployment services. Deployed across 10-15 SA schools. Shut down in 2020 after getting distracted by crypto/trading instead of focusing on the business.