Freelance full stack developer working remotely across web applications, product engineering, and infrastructure. I invest additional time in open source and focus on maintainable software, strong test coverage, and modernizing fragile systems by simplifying delivery and operations while strengthening quality through code review, pair programming, and technical mentoring.

Personal website: roschaefer.de

• Dialogbank: SvelteKit application for AI-assisted interviews and editorial publishing. I am helping replace a brittle workflow spread across Airtable, Voiceflow, and custom services with a single serverless application.
• DreamMall: Open-source social platform where I reworked delivery and infrastructure, replacing fragile manual deployments with self-managed Kubernetes on Hetzner and Terraform-based production-like preview environments.
• beteon: Automotive aftermarket software. We migrated an Electron desktop application to a cloud platform and increased the number of connected wholesalers from 3 to 240.
• 100eyes: Platform for audience engagement and crowd-based reporting in journalism, integrating WhatsApp, Telegram, Signal, Threema, and email for direct 1:1 communication between journalists and their communities.
• Ocelot.social: Community-built open-source social network. As Technical Lead, I worked on product architecture, GraphQL APIs, Neo4J in production, Kubernetes operations, onboarding contributors, and reviewing most contributions.

• git-splice: Git extension for contributing to other repositories from one monorepo: edit them as folders, test them together, and sync both ways with plain Git. The monorepo and the spliced repositories share no commits, so everyone else keeps working in each repository as before, and the documentation consists of tested example scenarios.
• hledger-document-check: Plain Text Accounting CLI for hledger that reconciles transactions requiring documentation with files on disk, detects missing or unbooked documents, checks amount plausibility, and generates an enriched journal for Fava's document view.
• hledger-elster: Plain Text Accounting CLI for hledger that automates German tax filing, generating traceable CSV and XLSX exports for the corresponding ELSTER.de forms, including derivations tax authorities can audit.
• roschaefer.de: My bilingual portfolio and resume site, built from a shared content source for the web, printable PDFs via Typst, and standards-compliant resume.json.
• Rundfunk mitbestimmen: Civic tech project that lets people symbolically decide how public broadcasting fees are allocated by assigning their contributions to individual programs. Covered by Zeit Online, Netzpolitik.org, Deutschlandfunk, and RBB.

TypeScript, Ruby, Python, SvelteKit, Vue, Tailwind, Apollo GraphQL, Ruby on Rails, Docker, Kubernetes, Terraform, Ansible, PostgreSQL, Neo4J, Netlify, Google Cloud, and Hasura.

I regularly give talks at meetups, conferences, and educational formats, and I enjoy helping people learn programming and full stack development.

• Talks and presentations: roschaefer.de
• Video playlist: YouTube
• Mentoring: Codementor