A luminous cinematic sci-fi hero image: the planet Saturn glows majestically on the right side of the frame, its pale golden-cream surface banded in warm honey, peach, and salmon tones, lit dramatically by sunlight from the upper right. Saturn's iconic ring system sweeps gracefully across the right half of the composition, glittering in layered bands of ivory, gold, and soft amber, with delicate translucent shadows where the rings cross the planet's body. The left two-thirds of the frame is warm cosmic space - deep indigo and midnight blue washed with a soft golden glow spilling in from the right, a sprinkle of crisp distant stars, and a dreamy muted-violet and rose nebula. Painterly stylised concept-art aesthetic in the spirit of Offworld Trading Company - bold colour blocking, atmospheric, hopeful, awe-inspiring.

Turn ideas into shipped software

AI integrations and custom web apps - built for businesses that care about quality

  • Shipped on time - projects go live, not just prototypes

  • Built for ROI - features that move the business, not just the codebase

  • Reliable in production - tested, monitored, ready for real users

Start a projectSee services

What I do

Services tailored to your goals

Four focus areas - each available as a one-off engagement, a fixed-scope project, or ongoing collaboration. Click any card for a deep dive.

Portrait photograph of David Siewert against a plain white background. He has short dark hair, wears a dark patterned button-up shirt over a black t-shirt, and looks directly into the camera with a calm, neutral expression.

AI Expert & Full-Stack Developer

About

  • 10+ years of professional full-stack development experience

  • Expert in modern TypeScript stacks, AI integration, and edge infrastructure

  • Performance- and UX-driven from the first sketch to the final deploy

I've built real-time, collaboration-heavy platforms like LEG.TJ, Contentoren, and Gruppenplan entirely from the ground up - product design, frontend, backend, and infrastructure.

My approach is product-driven: clarity, reliability, and long-term sustainability. Systems that scale gracefully and stay enjoyable to maintain. Strong in TypeScript, React, Solid, Node/Bun, Convex, and event-driven architectures.

For AI work, I focus on what actually delivers value - not demos.

Selected work

Recent projects

A snapshot - full case studies available on request.

LEG.TJ

National platform connecting government and development partners to plan, track, and improve education support in Tajikistan. Built to help manage $100M+ in education funding.

  • Solid.js
  • Convex
  • TypeScript
  • Tailwind
  • Cloudflare
Visit site
Screenshot of the LEG.TJ marketing homepage hero. Hero photograph shows Dushanbe in spring - snow-capped mountains and a distant cityscape behind blooming pink cherry-blossom branches. White overlaid headline reads "Strengthening Education Coordination in Tajikistan" with the subtitle "The DCC Coordination Platform unites donors, government, and partners to align efforts for transforming Tajikistan's education sector." Two CTA buttons sit centred below: "View events" and "View Resources". Top navigation links: About, Stakeholders, Projects, Events, Resources, English language switcher, light/dark toggle, Login.

Contentoren.de

AI-powered digital marketing platform that automates content creation, scheduling, and publishing - combining cutting-edge AI with human expertise.

  • Solid.js
  • Convex
  • AI
  • Cloudflare
  • Hetzner
Visit site
Screenshot of the Contentoren.de marketing homepage hero. Large German headline reads "KI-Marketing & Webdesign Agentur:" with the second line "automatisierte Growth-Systeme" highlighted in teal. The site navigation lists Growth Suite, Pakete, Cases, Branchen, Insights, Preise, with a black KI-Audit call-to-action button on the right. Two CTA buttons sit beneath the subhead - a black "Growth-System anfragen" and a light "Konzept ansehen" - over three feature stat cards: WEBSITE-LAUNCH 21 Tage, CONTENT-SYSTEM 30 Tage, AUTOMATION 24/7. Subtle violet-to-teal gradient background.

Gruppenplan.com

Real-time group planning for hotels, campsites, and tour operators. Room assignments, preferences, and collaborative workflows at scale.

  • React
  • Bun
  • Event Sourcing
  • Websockets
  • TypeScript
  • Cloudflare
Visit site
Screenshot of the Gruppenplan.com marketing homepage hero on a clean white background. Two pill-shaped chips above the headline read "Group travel" and "Room allocations" joined by a plus. The bold headline reads "Simplify group trip organization", followed by the subtitle "Automate room assignments and group coordination - Optimal distribution for groups of any size with just one click." A black "Start now" rocket button sits centred below. The top bar shows the GP logo, a language switcher (German / Deutsch), a light/dark toggle, and a Sign up / Sign in link.

Open source

Libraries & tools I maintain

Reusable building blocks I've extracted from production work and published for the community.

  • astro-ui

    A library of reusable UI components for Astro projects.

    CodePackageWebsite
    astro-ui logo

  • solid-ui

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

    CodePackageWebsite
    solid-ui logo

  • email-generator

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

    CodePackage
    email-generator logo

  • convex-auth-solid

    Build authenticated SolidJS apps lightning-fast with Convex.

    Code
    convex-auth-solid logo

  • utils

    A comprehensive collection of TypeScript utilities for common development tasks.

    CodePackage
    utils logo

  • pandoc

    A self-hosted Pandoc API for document conversion between 40+ formats.

    CodePackage
    pandoc logo

  • n8n-nodes-publer

    n8n node to connect with Publer.com social media management API.

    CodePackage
    n8n-nodes-publer logo

  • cfb2

    Zero-cost Backblaze B2 proxy on Cloudflare Workers - kills outbound bandwidth bills via the Bandwidth Alliance.

    CodePackage
    cfb2 logo

  • assets-optimizer

    Process, hash, and sync optimized web images and videos between local folders and any rclone remote.

    CodePackage
    assets-optimizer logo

  • website-content-pipeline

    Markdown content pipeline for scheduled website articles - handles frontmatter, featured images, and generated content lists.

    CodePackage
    website-content-pipeline logo

  • result

    A simple, type-safe Result type for TypeScript. Handle errors gracefully without try-catch soup.

    CodePackage
    result logo

  • ralph

    An autonomous opencode agent that loops through tasks with fresh context each iteration. Paired with taski for task management.

    CodePackage
    ralph logo

How we work

A simple, predictable process

No surprises. Just clear conversations, honest scoping, and steady delivery.

  1. 01

    Discuss

    We talk about your goals, constraints, and what success looks like. No pitch deck - just clarity.

  2. 02

    Design

    I propose solutions that balance cost, complexity, and user experience. You decide what to build.

  3. 03

    Build

    Clean, well-tested code shipped in tight increments. You see progress weekly, not at the end.

  4. 04

    Ship

    Confident deploys, monitoring, and handover. I stay available to keep things running.

Let's talk

Ready to build something that actually ships?

Reach out with a sketch, a problem, or even just a question. I respond within a day, usually faster.

Email meBook a meeting

or reach out on social media: