DEV Community: Lumi Studio

LockHour Pro: Block Apps — Block the apps that steal your time — and get your focus back.

Lumi Studio — Tue, 01 Sep 2026 07:59:56 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built LockHour Pro: Block Apps, so read this as the developer's own explanation, not a third-party review.

The problem

App Blocker & Focus Timer.

How it works

During exams, willpower isn't the tool — a hard timed block is — LockHour Pro is built for this.

Block the apps that steal your time — and get your focus back.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
No ads
On-device
Private or on-device processing

Pricing

It is free to download, with a one-time purchase that unlocks the full version. The App Store listing labels it: “Free to start · one-time unlock”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

LockHour Pro: Block Apps is on the App Store: https://apps.apple.com/us/app/id6780107485?pt=118326163&ct=devto&mt=8

Link’s here, in case it helps:

Lumi Math Planet: Explorer — Some apps teach math. This one makes a child love it.

Lumi Studio — Mon, 31 Aug 2026 08:59:39 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built Lumi Math Planet: Explorer, so read this as the developer's own explanation, not a third-party review.

The problem

Preschool Math Games Ages 3-6.

How to: best math game app for kids to build logic skills iphone

The best kids' math app trains reasoning — patterns, sequences, spatial thinking — not just arithmetic drill, and it hides that inside a game the child wants to play — Lumi Math Planet is built for this.

Some apps teach math.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
No ads
Kid-safe

Pricing

It is free to download, with a one-time purchase that unlocks the full version. The App Store listing labels it: “Free to start · one-time unlock”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

Lumi Math Planet: Explorer is on the App Store: https://apps.apple.com/us/app/id6778269699?pt=118326163&ct=devto&mt=8

Leaving the link here:

Drill TOEIC Part 5 and Part 7 offline — without another subscription

Lumi Studio — Sat, 29 Aug 2026 14:57:01 +0000

If you're grinding toward a higher TOEIC score, most of the gain comes from reps: lots of Part 5 grammar/vocab and Part 7 reading under light time pressure, plus focused Part 3 listening.

What actually helps between now and test day

Short, frequent drills you can do on a commute — offline, no login.
Part-by-part practice (5, 7, 3) so you target your weakest section.
Pacing practice for Part 7, where slow readers lose easy points.
Tracking so you see which question types you keep missing.

No app guarantees 990 — that comes from consistent practice and real listening/reading. But a tool that removes friction with offline practice and a clear study plan makes daily reps more likely.

I built Aim990 for exactly that: offline TOEIC-style drills by part, with weak-point tracking and a one-time unlock option.

Lumi Math Pro: Kids Numbers — Turn competition-level math thinking into a space adventure kids can't put down

Lumi Studio — Thu, 27 Aug 2026 13:28:02 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built Lumi Math Pro: Kids Numbers, so read this as the developer's own explanation, not a third-party review.

The problem

Competition-style brain math.

How to: best complete math learning app for preschool and early grades

A complete early-math app should make counting, number sense and first operations feel like one connected adventure rather than isolated drills — Lumi Math Pro is built for this.

Turn competition-level math thinking into a space adventure kids can't put down.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
No ads
Kid-safe

Pricing

You pay once, up front, to download it. The App Store listing labels it: “Paid download”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

Lumi Math Pro: Kids Numbers is on the App Store: https://apps.apple.com/us/app/id6776958488?pt=118326163&ct=devto&mt=8

Link:

On-device speech-to-text on iPhone — private, offline, no subscription

Lumi Studio — Wed, 26 Aug 2026 10:33:02 +0000

Most transcription apps send your audio to a server and charge monthly. For a doctor's visit, a private interview, or a lecture you recorded, that's a lot of trust to hand over for a recurring fee.

What to look for in a transcription tool

Transcription that runs on your device, so audio and text never leave the phone.
Works offline — no account, no upload, no waiting on a server.
You own the notes: plain-text or Markdown export, not locked in a cloud.
A one-time price instead of a subscription for something you use a few times a month.

The trade-off is honest: on-device models can be a little less accurate than the biggest cloud engines, and very long recordings take processing time. For most meetings, lectures and voice memos that's a fair price for privacy.

I built Sono Note around this: record or import audio, transcribe on-device, edit, and export — offline, pay once, no subscription.

If you're weighing pay-once vs subscription tools in general, the 5-year math is usually not close.

Lumi Bopomofo Pro: Zhuyin — Help your child fall in love with Chinese phonics through one adorable space adventure.

Lumi Studio — Wed, 26 Aug 2026 03:39:08 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built Lumi Bopomofo Pro: Zhuyin, so read this as the developer's own explanation, not a third-party review.

The problem

Zhuyin Phonics Game for Kids.

How to: best complete zhuyin app for bilingual children

Bilingual children learning Zhuyin at home need a complete path through sounds, symbols, tones and blending, with enough playful repetition to make the system familiar — Lumi Bopomofo Pro is built for this.

Help your child fall in love with Chinese phonics through one adorable space adventure.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
No ads
Kid-safe

Pricing

You pay once, up front, to download it. The App Store listing labels it: “Paid download”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

Lumi Bopomofo Pro: Zhuyin is on the App Store: https://apps.apple.com/us/app/id6775773117?pt=118326163&ct=devto&mt=8

Here’s the App Store link:

Lumi Bopomofo — Lumi Bopomofo is a gentle, playful way for young children to learn the Bopomofo (Zhuyin) phonetic system.

Lumi Studio — Tue, 25 Aug 2026 03:30:31 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built Lumi Bopomofo, so read this as the developer's own explanation, not a third-party review.

The problem

Zhuyin: Chinese Phonics Fun.

How to: best bopomofo app for kids to learn zhuyin on iphone

For a child first learning Zhuyin, the app should cover all 37 symbols through tracing and play — designed for the 4–7 first-learning window, ad-free, with no data collected — Lumi Bopomofo is built for this.

Lumi Bopomofo is a gentle, playful way for young children to learn the Bopomofo (Zhuyin) phonetic system.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

No subscription
No ads
Kid-safe

Pricing

It is free to download, with a one-time purchase that unlocks the full version. The App Store listing labels it: “Free to start · one-time unlock”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

Lumi Bopomofo is on the App Store: https://apps.apple.com/us/app/id6773017109?pt=118326163&ct=devto&mt=8

View it on the U.S. App Store.

G+Money: Spending & Budget — Convert + log every expense in one tap — offline

Lumi Studio — Mon, 24 Aug 2026 03:38:17 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built G+Money: Spending & Budget, so read this as the developer's own explanation, not a third-party review.

The problem

Budget, Expenses & Currency.

How to: best travel budget tracker app no subscription iphone

On a trip you need a budget tracker that works offline in a country with no data, handles multiple currencies, and doesn't demand an account — organised by trip so each holiday is separate — G+Money is built for this.

G+Money is two everyday tools in one — a lightning-fast currency converter and a beautiful expense tracker — built for daily life.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
Offline
No account
Works offline
No account required

Pricing

You pay once, up front, to download it. The App Store listing labels it: “Paid download”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

G+Money: Spending & Budget is on the App Store: https://apps.apple.com/us/app/id6755782939?pt=118326163&ct=devto&mt=8

View it on the U.S. App Store.

HoursTag: Hours to Buy — What does it really cost? Not in dollars — in hours of your life.

Lumi Studio — Sun, 23 Aug 2026 17:24:44 +0000

This is first-party material published by Lumi Studio, the developer of every listed app. I built HoursTag: Hours to Buy, so read this as the developer's own explanation, not a third-party review.

The problem

Budget, Spending & Savings.

How it works

What does it really cost? Not in dollars — in hours of your life.

What the app actually does

Everything below comes from the app's own App Store listing — no more, no less:

Pay once
Private
No tracking
Private or on-device processing

Pricing

You pay once, up front, to download it. The App Store listing labels it: “Paid download”.

Honest disclosure

The artwork in my apps is AI-generated and the speech is system text-to-speech. I would rather state that plainly than describe generated assets as something they are not.

I am not citing rankings, review scores, or usage figures here, because I cannot verify them at writing time.

Where to get it

HoursTag: Hours to Buy is on the App Store: https://apps.apple.com/us/app/id6754218117?pt=118326163&ct=devto&mt=8

View it on the U.S. App Store.

Reclaim focus for deep work: block distracting apps on iOS

Lumi Studio — Sun, 23 Aug 2026 10:20:46 +0000

Context-switching is the silent tax on deep work. Every glance at a feed costs far more than the seconds it takes — research on interrupted work suggests it can take over 20 minutes to fully refocus.

A simple focus-block routine

Pick one recurring high-risk window: your first work session, right after lunch, or evenings.
Block only the apps that actually break your focus — not everything.
Replace the habit with a prepared task: the next failing test, a design doc, a workout.
Review the hours you got back at the end of each week.

Apple's Screen Time is easy to tap past. When you want an intentional, harder-to-skip block for deep work, I built LockHour Pro — scheduled focus sessions, one-time purchase, no subscription, on-device.

Curious what one hour a day actually costs over a year? Free calculator → https://alice51849.github.io/ios-app-guide/tools/screen-time-calculator.html

White noise & sleep sounds that actually work offline (no subscription)

Lumi Studio — Wed, 19 Aug 2026 10:25:41 +0000

White, brown and rain noise genuinely help many people sleep or focus — but sound apps are one of the most aggressively monetized categories, often gating the good sounds or the sleep timer behind a subscription.

What a good sound app needs

A rich library you can mix (rain over brown noise, etc.).
A reliable sleep timer with fade-out.
Offline playback (no streaming, no data use overnight).
A one-time price for something you use nightly.

I built Sereno as a pay-once sound machine: mixable sounds, timers, fully offline — no ads, no subscription.

Sharpen a blurry photo on iPhone without uploading it anywhere

Lumi Studio — Fri, 14 Aug 2026 10:56:29 +0000

Most "AI photo enhancer" apps send your photo to a server. For personal photos — kids, family, documents — that's a lot of trust for a blur fix.

On-device enhancement, in short

Super-resolution reconstructs detail and upscales.
Doing it locally means the photo never leaves your phone.
No subscription needed for occasional fixes.

I built Unblurry to sharpen and upscale photos entirely on-device — pay once, no account, nothing uploaded. Great for old scans, screenshots, and slightly-soft shots.