Dargel Solutions · Digital Products

Digital products with verifiable substance.

Source-backed guides and playbooks with working calculators and templates. Published under Adrian Verdan, the publishing imprint of Dargel Solutions. Gumroad handles the sale and payment.

Current products

Three practical guides for starting and automating a small business.

Cover of “Registering a Kleingewerbe in Germany”

Registering a Kleingewerbe in Germany

The step-by-step guide to starting a small business in Germany, from the decision to your first income-expense statement. Written in English for expats, German terms explained.

  • 9 chapters, HTML bundle plus PDF
  • 4 calculators, example income-expense statement (XLSX/CSV), checklist
  • Legal status July 2026, language English

12.90 € excl. VAT

View the Kleingewerbe guide

Cover of The AI-First Operating Playbook

The AI-First Operating Playbook

A practical playbook for AI automation in small businesses — with an ROI calculator and working templates. Written in English.

  • 9 chapters, HTML bundle plus PDF
  • ROI calculator, 4 XLSX templates, 3 Markdown tools
  • Data as of July 2026, language English

39 € excl. VAT

View the AI-First playbook

Cover of Orchestrating AI Agents — score motif in dark petrol with an amber approval ring

Orchestrating AI Agents

A practical playbook for making AI models work together — reviewer patterns, routing, research verification and cost control. The multi-agent deep dive behind the AI-First Playbook.

  • 10 chapters, HTML bundle plus 66-page PDF
  • Interactive cost calculator, 2 XLSX workbooks, prompt pack
  • Data as of July 2026, language English

39 € excl. VAT

View the AI agents playbook

Quality principles

How we work.

Source-backed

Every number and every deadline is checked against primary sources, and the data status is dated. No unsupported claims.

AI-assisted, human-reviewed

Created with AI support, openly disclosed in the spirit of EU AI Act Art. 50, and editorially reviewed before every release.

Honest previews

Real excerpts and working calculator demos instead of marketing claims. You see what is inside before you buy.

Free knowledge

Check the essentials before you decide.

Our free overview explains how to register a Kleingewerbe in Germany, including typical costs, deadlines, and the small-business VAT thresholds, with direct links to official sources.

Registering a Kleingewerbe: steps, costs, and deadlines →

What one documented multi-agent run actually caught →

All knowledge articles →

Outlook

What comes next.

All three titles are available in German and English — one product per language. More products are in the works.

Hear about new releases first: follow the imprint on Gumroad.