I use Adobe Acrobat for one thing: watermarking PDFs before delivery.
That's it. One feature. $20 a month.
So I built Hiyoko PDF Vault — a native Mac app that handles everything
I actually need, completely offline, for a one-time price.
The problem
Every time I needed to watermark a PDF, I had two options:
- Pay Adobe $20/month for a feature I use maybe twice a week
- Upload confidential files to a sketchy free online tool
Neither felt right. So I spent a few days building something better.
What I built
Hiyoko PDF Vault is a macOS-native PDF toolkit built with Rust + Tauri v2.
It runs completely offline. No servers. No subscriptions.
Features:
- Watermark (text/image · opacity · angle · position · real-time preview)
- Watermark presets — switch between "Draft" and "Final Delivery" in one click
- AI OCR engine (Apple Vision) — convert scanned PDFs to searchable documents
- AES-256 encryption & decryption
- Metadata sanitization (remove author, date, app name)
- PDF merge, split & compression
- Bates numbering (for legal & academic use)
- Blazing fast batch processing powered by Rust
Why offline matters
When I watermark a PDF, it usually contains client work or confidential documents.
Uploading that to a random website never felt safe.
With Hiyoko PDF Vault, everything stays on your Mac.
No data ever leaves your machine.
The tech behind it
- Rust + Tauri v2 — native Mac performance, tiny memory footprint
- lopdf — PDF structure editing, watermark injection, metadata removal
- qpdf — AES-256 encryption
- Apple Vision (via Swift) — OCR and searchable PDF generation
- rayon — parallel batch processing
How it compares
Adobe Acrobat: $20/month — powerful but expensive and heavy
PDF Watermark: $9.99 — watermark only, nothing else
Free online tools: free — but your files go to someone's server
Hiyoko PDF Vault: $29.90 one-time — watermark + OCR + encryption +
merge/split + batch processing, all offline.
Pays for itself in 1.5 months of Adobe.
Try it
🐤 Hiyoko PDF Vault on Gumroad — $29.90
Also check out my other Mac tools for Android users:
🐤 HiyokoLogcat — free & open source
🐤 HiyokoKit — $49
Would love feedback from anyone who's been in the same situation! 🐤
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