# NibFlow — Fountain Pen Humidity Guide

> Fountain Pen Humidity Guide (iPhone/iPad app by JUHWAN PARK.)

- Source: https://appshunter.io/ios/app/nibflow/id6762325529 (this page in markdown: same URL + `.md`)
- Developer: [JUHWAN PARK](https://appshunter.io/developer/1790125318)
- Category: Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 13.0 · 29 MB
- Languages: American English
- Released: 2026-04-21
- Data updated: 2026-07-10
- User reviews in markdown: https://appshunter.io/ios/app/nibflow/id6762325529/reviews.md

## What is NibFlow?

Stop guessing which fountain pen to use today. NibFlow checks your local humidity and temperature, then scores every pen + ink + paper combo in your collection — so you know which one flows best right now.

Fountain pen users know the frustration: an ink that wrote flawlessly yesterday feathers or dries out today. The reason? Weather changed. Humidity, temperature, and dew point all affect how ink flows through your nib.

HOW IT WORKS
1. Add your pen + ink combo: select nib size, ink type, wetness, and paper grade.
2. NibFlow fetches your local weather and calculates a Flow Score (0–100) across four axes: dry risk, feathering, dry time, and bleed-through.
3. See your daily score, care tips, and which combo to use today.
It takes 15 seconds to set up. No account required.

YOUR DAILY FLOW SCORE
Each combo gets a score from 0 to 100 based on four factors: how likely your nib dries out, how much your ink feathers on paper, how long it takes to dry, and whether it bleeds through. The score updates every time weather changes.

CARE TIPS
Get daily suggestions tailored to your combo: "Cap your EF between paragraphs today" or "Switch to heavier paper — bleed risk is high."

Upgrade to Pro for deeper insights:
- Unlimited pen + ink combos with daily ranking
- Full 4-axis breakdown with cause explanations
- 7-day flow forecast
- Brand-level paper grades (Tomoe River, Rhodia, Clairefontaine, and more)
- Morning flow alert notifications
- Collection statistics

PRIVACY FIRST
All your pen and ink data is stored locally on your device. No account needed. No tracking. Location is used only to fetch weather data from Open-Meteo. Your coordinates are never stored on any server.

This app provides flow estimates based on general relationships between weather conditions and ink behavior. It is not a substitute for hands-on writing experience. Actual performance varies by specific ink formulation, nib condition, and paper brand.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Pro — Full Access | $4.99 | per month |



## Version history (last 1 release)

### 1.0.0 — 2026-04-22

No release notes.

## More apps by JUHWAN PARK

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All apps by JUHWAN PARK: https://appshunter.io/developer/1790125318

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-10.*