The same sentence posted three times on Threads: LockDay, a lock-screen planner from a Vietnamese indie dev, charted in 50 countries over 6 weeks

A Vietnamese indie developer built an app that combines to-dos, calendar and notes into a single iPhone lock screen wallpaper that updates itself. He spent no money on ads. He posted the same blurb on Threads over and over, and a Thai blogger wrote a tutorial for it. Within 6 weeks of launch it had about 2,300 ratings worldwide and charted in the Productivity Top Grossing lists in Taiwan, Korea and Russia. The numbers are small, but every step is visible and can be copied. Below: what it is, how users found it, how much money it makes, who the competitors are, and whether you should follow it.

The same sentence, posted three times

On Nov 2026 3, Vietnamese developer Đạt Tiến Phạm (Threads account @ptd1099,4,296, followers, bio says "Solo Dev") posted with three lock screen screenshots:

Xin chào mn mình làm một cái app để giúp ghi nhớ các việc cần phải làm ngay trên màn hình khoá app free mong các bạn ủng hộ 😁 — Hi everyone, I made an app that helps you keep your to-dos right on your lock screen. It's free, please support it.

He had posted this before. In Oct 15 it got 425 likes; in Oct 22 he posted it again and got only 84 likes. On Nov 3 he posted it a third time, word for word, with a different set of screenshots. By 11-06 it had 5,300 likes, 783 reposts and about 1,000 shares. He added a comment underneath: "The app is called lockday, search it on the App Store or CH Play."

Two days later LockDay climbed in Vietnam's App Store Productivity free chart from over a hundred to #16 (11-05). On 11-06 Vietnam added 23 ratings in a single day, its biggest day in those 10 days (Vietnam App Store chart and ratings, 10-28 to 11-06).

The Vietnamese reviews spell out the path. On Sep 29: "Saw it on Threads, thought it looked good, downloaded it, the app is cute." On Sep 28, two reviews: "You said free on Threads, why do I have to pay to show it on the lock screen?" That means he was already posting on Threads in the first week after launch on Sep 23.

What it is

iOS doesn't let third-party apps change the lock screen, only add a few tiny widgets. LockDay gets around this: inside the app, it combines your Eisenhower matrix tasks, events from the iPhone Calendar, a monthly calendar, a today timeline, countdowns, year progress and notes into one image, with your own photo as the background. Then you set an automation in Shortcuts that periodically sets that image as your lock screen wallpaper. It looks like a self-updating lock screen planner.

Prices on the App Store (US store, 11-06):

The free version works, and Pro unlocks all templates and styles, unlimited tasks and notes, recurring tasks and iCloud sync (store description). But users themselves are unclear on what's free: some Vietnamese users say showing the calendar on the lock screen is free, others say showing it on the lock screen requires payment. A one-star Korean review mentions "4,400 won", roughly $3, which is the monthly price. The Android version only reached Google Play in Oct 30, under the developer name LockWaves Limited. By 11-06 it had 223 installs, with in-app purchases of $3.99–24.99.

The developer had previously made the calorie tracker Noms, RedMode, Puzz AI and the fishing log Glub, the most-rated of which has 89 ratings. LockDay is the first one that really took off.

How big is it, and is it real?

Ratings by store (App Store, 11-06): Thailand 684, Korea 285, Vietnam 221, Japan 180, Malaysia 161, Taiwan 150, US 94, Hong Kong 71, Ukraine 61, Russia 53. It has appeared in 57 stores and charted in the Productivity category in 40 of them over 10 days. It has never entered any store's overall chart.

Across all stores it added 20–70 ratings a day, with no single-day spike. Within 2–4 days of launch, Taiwan, Korea, Vietnam and Thailand each had written text reviews. The reviews are full of specific complaints and feature requests, which doesn't look like faked activity.

Where users come from

First: the developer posting on Threads himself. The three Vietnamese posts above are just the ones that are visible. Search results also show Spanish posts on his account ("Bro, I've used an iPhone for 8 years and only just learned you could do this, why didn't anyone say so?") and Malay posts ("iPhone users' lives are a mess, this will save you"). In the comments someone asked "what app is this" and he replied "lockday app bro". It's written as an ordinary user who found a tip, not a developer pushing a product. The full text of these posts can't be opened, and views and likes aren't visible.

Second: a Thai blogger wrote a tutorial. On Oct 5, Thai X user @reallmerrii posted a four-image LockDay setup tutorial: set up the Shortcut first, add tasks, and finally "don't forget to tap Update Lock Screen". By 11-06 it had 111k views, 2,700 likes and 1,600 bookmarks. Her bio reads "Reviews · DM for Work only · Aff link". Inferred, she's a review account taking brand deals, though whether this post was paid can't be confirmed. At the same time, a Lemon8 post (a popular Thai recommendation community) titled "Put a planner on your lock screen" had 2,334 likes and 1,349 bookmarks. Thailand is its biggest store, and these posts are the most direct explanation.

Third: the need had already been educated. Similar apps had been running short-form video in these countries for about half a year. The Vietnamese-language LockScreen Calendar Maker got 156k views on a single TikTok in July. Ink got 41k views on a single video in September. In August there was still an English Threads post saying "iPhone users put this on their lock screen and never forget things again". Users already knew a lock screen could show a calendar, so LockDay didn't have to explain it.

Fourth: multilingual store listings. At launch it localized into 32 languages, with names adapted per store: Korean "LockDay: 투두리스트 & 플래너", Japanese "LockDay: ToDoリスト&スケジュール", Hong Kong/Taiwan "LockDay: 待辦清單與計畫", Russian "Список дел и планер". This means people arriving from those posts can find it in search, and it catches search traffic already primed by similar apps (inferred, search volume isn't visible).

There's also a Korean review from Sep 26 that says "I installed it after seeing an ad", so it has probably run some ads. Where and how much can't be seen.

How much money

Best Top Grossing ranks: Taiwan Productivity #30, Russia #40, Korea #49, Malaysia #58, Hong Kong #62 (10-28 to 11-06). These are category charts in mid-sized stores, so the bar isn't high. Based on about 2,300 ratings, a $3.99 monthly subscription and $20 lifetime, inferred monthly revenue is in the low thousands of dollars. This hasn't been verified. Two five-star Russian reviews say "want to buy the annual plan, can you pay from Russia?", so money from that store isn't coming in yet.

The reviews show plenty of people buying the lifetime version (Korea and Taiwan both), and some subscribing for a month and then cancelling: "Researched the paywall for half an hour, cancelled right away" (Taiwan, 10-20).

Who it's competing with

The category is already crowded in Asia, and many competitors are also Vietnamese developers:

LockDay took off faster than Ink. Inferred, that's because it bundles more features, localizes more carefully, and the developer is better at posting. It doesn't have anything others can't build.

What users are complaining about

Almost all the negative reviews are about one thing: Shortcuts.

"The setup is too hard, I went around in circles, you have to configure it in Shortcuts and set a timed update. Every time I add a task I have to update the lock screen manually... I've already deleted it." — Thailand, 9-27, one star

"I followed the instructions and set up the automation, deleted and redid it too, and it still says an unknown error occurred and won't update." — Korea, 10-12, one star

"After the update everything changed, I can't understand any of it. I bought the app and can't use it." — Korea, 10-23, three stars

The positive reviews point to the other side of the same thing: "As long as you get through the initial setup, it's the best app" (Korea, 10-22).

The rest are feature requests, which show who the users are: lunar calendar (requested in both Vietnam and Korea, "parents' birthdays, ancestor rites and holidays are all on the lunar calendar"), shift schedules (Taiwan, "I work rotating shifts"), subtasks, seeing next month from the lock screen, and iPad sync.

If it were you

One-line verdict: the lock screen planner category is already crowded, and a generic version isn't worth building. What's worth learning is LockDay's playbook: one person, zero budget, native Threads posts plus multilingual store listings, and within 6 weeks it had reached 50 multiple countries.

Who this is for: indie developers who can already build for iOS and can finish a small tool alone in two or three weeks, and who are heavy users of Threads, Lemon8 or Xiaohongshu themselves and can write a "I found a trick" style post.

Not for: anyone hoping to make big money in this category (the charts are category charts, and the monthly revenue inferred from ratings is only a few thousand dollars); anyone wanting to target the English market (the US store has only 94 ratings); anyone unwilling to walk users through setting up shortcuts one by one in the reviews and DMs.

How to do it: build the part it does badly instead of making another LockDay. Three angles: ① Android: Android can truly take over the lock screen without Shortcuts. LockDay's Android version just launched with only 223 installs. ② Niche audiences: lunar calendar and holidays (Vietnam, Korea, Chinese-speaking users), shift schedules (nurses, service workers), student timetables. Reviews keep asking for these. ③ Japan: a lock-screen-notes-only app has 21k ratings in Japan, while LockDay has only 180 there, and Japan has no full-featured "lock screen planner" yet (inferred). Price it like it does: about $3–4 monthly, $12 yearly, $20 lifetime, and make setup a guided step-by-step flow so users don't have to dig through Shortcuts themselves.

How to get users: copy his approach. On Threads, post in the target language a "regular user discovered a trick" post with three lock screen screenshots and no link. When people ask in the comments, name the app. If one post flops, repost the same thing a week later. His third try is the one that took off. In Thailand and Vietnam, find Lemon8 and X review accounts to write setup tutorials. The tutorial itself is the content, because the setup is hard, which is exactly why people want the tutorial.

When to move: as early as possible, ideally before 2027 January. The category gets new small teams from Vietnam and Thailand every month. Claiming "lock screen + a specific audience" in one language first matters more than building something better later.

What would mean you read it wrong: ① LockDay's daily new ratings in Thailand and Korea drop to single digits in December. That would mean this wave came from the posts, and the volume stops when the posts stop. ② Apple opens larger lock screen widgets or interactive lock screens in a new system release. Then the workaround loses its value. ③ You post three times in the same style on Threads and each post gets fewer than 100 likes. That would mean the opportunity in your language is already taken.

---

Data and sources: App Store charts, ratings and reviews across 115 stores (2026-10-28 to 11-06); App Store US and Korean store pages and iTunes lookup (11-06); Google Play LockDay Android page (11-06); Threads @ptd1099 profile (11-06 scrape, post dates as shown on the page); X @reallmerrii 10-05 posts; Lemon8 Thailand posts; TikTok videos of similar apps (11-06). Monthly revenue is inferred from rating counts and prices and has not been verified.