Nenrin — Pen & Ink Collection

Bring your collection with you — import is free, always. Pens, inks, the rotation, bottles that behave like bottles. No accounts, no tracking. Pay once, yours forever.

Nenrin (年輪 — "tree rings") is a home for your fountain pen and ink collection. Not a database. A place.

BRING YOUR COLLECTION WITH YOU Already keeping your pens in another app or a spreadsheet? Nenrin reads your CSV export and your collection walks in with you — pens, inks, details intact. Import is free for everyone, at every tier, always. Nothing held back, nothing behind a door.

THE COLLECTION, BEAUTIFULLY KEPT Add a pen in four taps — a deep catalogue of brands, models and colorways meets you as you type, and anything it doesn't know you can always write by hand. Photos framed the way you choose, nib and filling system at a glance, and room for the story — where it came from, what day it was. The things a spreadsheet forgets.

INKS THAT LIVE Your bottles stand on a shelf — many in their brand's own shape — and behave like bottles: the ink leans when your phone tilts, sloshes when you tap, settles its shimmer while you're away. Fill levels move a real waterline. Sheen and shimmer are captured as colors, not checkboxes.

THE ROTATION Ink a pen — from the bottle, a converter, or a cartridge — and it enters the rotation. See what's inked with what and for how long, mark a pen for cleaning, and let a quiet reminder tell you when a fill has sat too long.

GRAILS The pens you're hunting. A target, what you've set aside, and the notes — where you spotted it, what the nib should be. When the day comes, one tap converts the grail into an owned pen with its story intact.

THE PALETTE One tap composes your collection into a card — your pens as a quiet palette, light or dark — made for the communities you're already part of.

YOURS, QUIETLY

• Syncs through your own iCloud. No accounts, no feed, no AI.
• No analytics, no ads, no tracking. We can't see your pens.
• Export everything as JSON and CSV, free forever. Your data is yours.

Free for up to three pens and three inks — everything included, import included. Nenrin Pro is a single purchase (no subscription, ever): unlimited pens and inks, alternate app icons, and shares without the small mark.