Lightning Speed
Achieves 90+ scores on Google PageSpeed Insights for exceptional load times and user experience
David Siewert
Senior Full-Stack Developer
10+ years of professional development experience
Expert in modern Typescript/Web-frameworks and tools
Performance- and UX-driven in all stages of development
About
Senior full-stack engineer specializing in building complex web platforms from the ground up, spanning product design, real-time systems, and scalable infrastructure.
I've built real-time, collaboration-heavy platforms such as Leg.tj, Gruppenplan.com, and Postmaschine.com entirely from the ground up — spanning product design, frontend architecture, backend systems, and infrastructure.
My approach is product-driven: I focus on clarity, reliability, and long-term sustainability, ensuring systems scale gracefully and remain enjoyable to use and maintain.
Strong in React.js / Solid.js, Node.js / Bun, Convex, and event-driven architectures, with a focus on quality, maintainability, and stability.
Projects
LEG.TJ
The national platform that connects government and development partners to plan, track, and improve education support in Tajikistan
Astro Website
Solid.js Web App
Convex Backend
TypeScript
Tailwind
Cloudflare Network
Backblaze B2
Postmaschine.com
Postmaschine is the smarter way to handle digital marketing, combining cutting-edge AI with human expertise to fully automate content creation, scheduling, and publishing
Astro Website
Solid.js Web App
Convex Backend
TypeScript
Tailwind
Cloudflare Network
Backblaze B2
Hetzner VPS
Gruppenplan.com
Efficiently organize and optimize group. Easily assign individuals to rooms, manage group preferences, and streamline planning for hotels, campsites, tents, and more. Ideal for tour operators, teachers, and event organizers.
Astro Website
React.js Web App
Bun Backend
TypeScript
Cloudflare Network
Hetzner VPS
Open Source
astro-ui
A library of reusable UI components for Astro projects.
TypeScript
Tailwind CSS
Astro
Component library
solid-ui
A library of reusable UI components for Solid.js projects.
TypeScript
Tailwind CSS
Solid.js
Component library
email-generator
A lightweight, self-hostable service for rendering HTML emails.
React Email
TypeScript
Cloudflare Worker
Microservice
convex-auth-solid
Build authenticated SolidJS apps lightning-fast with Convex.
Solid.js
Convex
TypeScript
Authentication
utils
A comprehensive collection of TypeScript utilities for common development tasks.
TypeScript
Library
pandoc
A self-hosted Pandoc API for document conversion between 40+ formats.
TypeScript
Bun
API
Document conversion
Experience
Lead Developer of LEG.TJ
October 2025 - December 2025Eductrade / EU Delegation in TJ
(3 Month)Designed and built the entire platform from scratch, from Design/UI/UX to infrastructure
Empowered donors to manage over $100M in education funding across Tajikistan
Developed a web app with Convex backend for real-time data sync and collaborative workflows
Architected and deployed a scalable object storage infrastructure for securely storing official reports, policies, and long-term institutional data
Lead Developer of Postmaschine.com
July 2025 - September 2025Semesterkur UG
(3 Month)Built a modern Solid.js interface optimized for UI/UX responsiveness, and top-tier performance
Integrated Convex runtime to power real-time data synchronization and interactions
Automated end-to-end content production with AI to create dynamic, on-brand multimedia content at scale
Lead Developer of Gruppenplan
January 2022 – June 2025earlywings GmbH
(3.5 years)Analyzed, modeled, and implemented business processes in software (e.g., using EventStorming)
End-to-end development and operation of a complete full-stack application
Developed a real-time system enabling seamless team collaboration
Implemented authentication, authorization, role-based access control (RBAC), and access management
Designed and implemented an event-driven architecture for complete process traceability
Created intuitive user interfaces with a strong focus on speed and usability and responsiveness
Developed multilingual support (English and German) for the entire application
Secured infrastructure against DDoS attacks and cyber threats using Cloudflare
Set up, configured, administered and hardened all Linux servers
Full-Stack Software Developer
July 2017 – December 2021assona GmbH
(4 years)Developed server-side REST services in Java using Spring Boot 2.0
Built Kubernetes infrastructure using Rancher and Helm
Created a custom CI/CD pipeline with GitLab CI, including unit, integration, and system tests
Developed frontend applications with TypeScript, React.js, and Material UI (MUI)
Set up, integrated, and operated Keycloak for authentication and authorization
Introduced E2E testing based on Playwright
Designed and built microservices using event-sourcing architecture
Startup Development
September 2016 – August 2017Early state startup
(1 year)Conceptualized business model for startup
Introduced agile and lean startup principles to structure development efforts
Collaborated closely with a small founding team across technical and business roles
Learned function programming and Scala
Software Developer
October 2013 – August 2016ID Information und Dokumentation im Gesundheitswesen GmbH & Co. KGaA
(3 years)Developed reporting tools for the German Federal Cancer Registry Law
Migrated GWT web applications to AngularJS
Established Continuous Integration (CI) with Jenkins
Education
Master of Science in Informatics
Technical University of Berlin
2013 – 2015Thesis:Using Machine Learning to Improve the Quality of Search Algorithms in General Game Playing
Bachelor of Science in Informatics
Technical University of Berlin
2009 – 2013Thesis:Development of artificial intelligence for a multiplayer real-time game
Skills
languages
Java
Scala
JavaScript
TypeScript
frontend
Solid.js
React.js
Next.js
Astro
Vite
Rsbuild
HTML
CSS
Tailwind
tools
Git
GitHub
GitLab
linear.app
Docker
CI/CD
Jenkins
backend
Bun
Node.js
SQL
SQLite
Litestream
Cloudflare
Kubernetes
Convex
OS
Debian
Fedora
Bash scripting
Fish shell
architecture
Functional Programming (FP)
Test-Driven Development (TDD)
Domain-Driven Design (DDD)
Event Sourcing (ES)
Command Query Responsibility Separation (CQRS)
Microservices
RESTful API Design
teamwork
Agile methodologies (Agile, Scrum, Kanban)
Mentoring and coaching junior developers
Structured coordination of tasks, processes, and documentation
Technical
Technical Features of this Website
Features a modern static site like this one should have in2026
Unhackable Security
100% secure static architecture with zero database or server-side vulnerabilities
Edge-Hosted
Deployed on Cloudflare Pages for instant global edge network distribution
Zero Maintenance Cost
100% free infrastructure with no recurring hosting or maintenance fees
CDN Accelerated
Cloudflare CDN ensures ultra-low latency and fast content delivery worldwide
Accessibility First
Semantic HTML5 with proper ARIA labels, landmarks, and logical section divisions
Optimized Readability
Carefully crafted typography and spacing for effortless reading experience
Light/Dark Mode
Seamless light/dark theme switching that respects system preferences
Fully Responsive
Pixel-perfect adaptation across all devices, screen sizes, and orientations
Privacy-First Analytics
Internal routing bypasses adblockers for accurate, uninterrupted insights
Media Optimization
Aggressively compressed images, icons, and SVGs without quality loss
Smart Caching
Custom _headers configuration for optimal browser and edge caching strategies
SSL/TLS Encrypted
Automatic SSL/TLS certificates ensuring end-to-end encrypted connections
AI-Assisted Development
Enhanced with v0 and OpenCode for rapid, intelligent development
Human-Touch
Hand-written and/or meticulously reviewed AI code by an experienced developer
Steps
A collaborative approach focused on delivering quality results
Discuss
01Let's talk about your project goals, challenges, and vision. I'll listen carefully to understand your needs.
Design
02I'll create thoughtful solutions that balance aesthetics, functionality, cost and user experience.
Build
03Clean, scalable code that brings designs to life with attention to performance and maintainability.
Ship
04Deploy with confidence. I ensure smooth launches and provide support to keep things running perfectly.
Ready to Build Something Amazing?
Let's collaborate on your next project.
Get In Touch