Dirk Holtwick
Software Development & Privacy-Focused Apps
I am a passionate software developer for web, mobile and desktop applications from the Ruhr area in Germany. I currently develop and distribute free and commercial applications.
My ambition is to develop useful applications for communication and knowledge storage while creating the best possible solution for privacy protection. My many years of experience in large companies in the development of software products for a broad target group help me to achieve this.
Apps
All projects
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Latest posts
All postsCollaborative Rich Text without YjsWhy I don't use a character-level CRDT like Yjs for collaborative rich text, but merge words as spans in an ordered map with fractional keys: readable JSON, auditable transactions, no merge code.September 8, 2026'/%3e%3cg%20transform='rotate(45%20512%20512)'%3e%3c!--%20Webbing%20on%20the%20shoulder-belt%20diagonal%20--%3e%3crect%20x='-360'%20y='402'%20width='1744'%20height='220'%20fill='url(%23webbing)'/%3e%3crect%20x='-360'%20y='426'%20width='1744'%20height='10'%20fill='%234B5563'%20opacity='0.7'/%3e%3crect%20x='-360'%20y='588'%20width='1744'%20height='10'%20fill='%234B5563'%20opacity='0.7'/%3e%3c!--%20Buckle%20housing,%20tongue%20slot%20cut%20out%20so%20the%20webbing%20shows%20through%20--%3e%3cpath%20fill='url(%23housing)'%20fill-rule='evenodd'%20d='%20M%20353%20362%20H%20671%20A%2076%2076%200%200%201%20747%20438%20V%20586%20A%2076%2076%200%200%201%20671%20662%20H%20353%20A%2076%2076%200%200%201%20277%20586%20V%20438%20A%2076%2076%200%200%201%20353%20362%20Z%20M%20320%20452%20A%2016%2016%200%200%201%20336%20468%20V%20556%20A%2016%2016%200%200%201%20304%20556%20V%20468%20A%2016%2016%200%200%201%20320%20452%20Z%20'/%3e%3c!--%20Release%20button%20--%3e%3crect%20x='411'%20y='442'%20width='260'%20height='140'%20rx='54'%20fill='url(%23button)'/%3e%3c/g%3e%3c/svg%3e)
BX AppClaude in a macOS SandboxA hands-on report on AI coding tools inside Apple's Seatbelt sandbox: how Claude tries to get around restrictions, what really needs protecting, and how the app BX came out of it.Selling software worldwide from EuropeVAT, payment providers and merchants of record: why selling software worldwide from Europe is so hard – and which providers are actually left.June 15, 2026
Receipts AppReceipts Space 3.6An update with improvements to everyday workflows. Here’s a quick overview of the key changes.May 21, 2026
PDFify AppPDFify 5.0: Sharper OCR, Smarter CompressionPDFify 5.0 brings Tesseract 5 OCR optimized for Apple Silicon, automatic language detection via Apple Vision, four new compression modes, and full French localization.April 16, 2026 BX AppMe, the AI, and Our SandboxA hands-on report about using the bx sandbox for macOS, with a special focus on AI and VSCode.
BX AppClaude in a macOS SandboxA hands-on report on AI coding tools inside Apple's Seatbelt sandbox: how Claude tries to get around restrictions, what really needs protecting, and how the app BX came out of it.Selling software worldwide from EuropeVAT, payment providers and merchants of record: why selling software worldwide from Europe is so hard – and which providers are actually left.June 15, 2026 Receipts AppReceipts Space 3.6An update with improvements to everyday workflows. Here’s a quick overview of the key changes.May 21, 2026 PDFify AppPDFify 5.0: Sharper OCR, Smarter CompressionPDFify 5.0 brings Tesseract 5 OCR optimized for Apple Silicon, automatic language detection via Apple Vision, four new compression modes, and full French localization.April 16, 2026 BX AppMe, the AI, and Our SandboxA hands-on report about using the bx sandbox for macOS, with a special focus on AI and VSCode.