David Siewert

Full-Stack TypeScript Developer

10+ years of professional development experience

Expert in modern Typescript/Web-frameworks and tools

Performance- and UX-driven in all stages of development

Portrait of David, sitting in an office chair.

About

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
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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
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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
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Open Source

astro-ui

A library of reusable UI components for Astro projects.

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TypeScript Tailwind CSS Astro Component library

solid-ui

A library of reusable UI components for Solid.js projects.

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TypeScript Tailwind CSS Solid.js Component library

email-generator

A lightweight, self-hostable service for rendering HTML emails.

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React Email TypeScript Cloudflare Worker Microservice

utils

A comprehensive collection of TypeScript utilities for common development tasks.

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TypeScript Library

Experience

Lead Developer of LEG.TJ

October 2025 - December 2025

Eductrade / EU Delegation in TJ

(3 Month)

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 2025

Mora Montage 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 2025

earlywings 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 2021

assona 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 2017

Early 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 2016

ID 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 – 2015
Thesis: Using Machine Learning to Improve the Quality of Search Algorithms in General Game Playing

Bachelor of Science in Informatics

Technical University of Berlin

2009 – 2013
Thesis: 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

Steps

A collaborative approach focused on delivering quality results

Discuss

01

Let's talk about your project goals, challenges, and vision. I'll listen carefully to understand your needs.

Design

02

I'll create thoughtful solutions that balance aesthetics, functionality, cost and user experience.

Build

03

Clean, scalable code that brings designs to life with attention to performance and maintainability.

Ship

04

Deploy 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