We build for ourselves, too.
Products that earn us revenue, and open-source tools we use ourselves. That's how we know what operations, support and paying customers mean day to day.
Live, Own venture
die macher
Over 220 days
running since 2026
Our own venture in Metzingen: one point of contact for renovation, conversion and fit-out, every trade from a partner network. Behind it an AI-assisted project platform we run ourselves. Customers describe their project in one sentence, by text or voice, and Claude breaks it down into trades. In the portal, trade businesses keep a site diary with text, voice and photos and submit quotes and invoices; customers see schedule, budget and documents, decide on quotes and invite observers. Permissions per project role, access by invitation, withdrawal right inside the portal.
Next.js, Postgres, Vercel AI Gateway, Vercel Blob, Better Auth
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Live, Own venture
GymLabs
Over 2,400 days
running since 2020
Our own venture. Product development, operations and market from one team. It is why we think about operations, support and revenue when we build for clients, not just about shipping.
Next.js, Node, Postgres, Vercel
VisitOpen source
Tools we use ourselves and share openly.
Open source, 2026
@kevludwig/lexware-office
If you automate invoices and vouchers in Lexware Office, you don't have to write the client and the domain logic yourself.
TypeScript client with domain logic for the Lexware Office Public API, no framework. On top of it, an extension for the agent framework eve. Our own assistant uses it for incoming and outgoing invoices, quotations, contacts and payment reminders.
TypeScript, Node 24, eve, MIT, v0.1.0
Independent project, not affiliated with Lexware or Haufe-Lexware. “Lexware Office” and “lexoffice” are trademarks of their owners and are named here only to identify the API.
GitHubnpm: @kevludwig/lexware-officenpm: @kevludwig/eve-lexware-office
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We build SaaS for others, too. From the first version to the first paying customer.
“You can simply rely on him.”
5.0 from 8 Google reviews
As of October 6, 2026. We don't verify whether reviews come from clients.On working days we usually reply within 24 hours.
Next open project start: Monday 26 October.