A singing app with only 114 ratings squeezed into Japan's music Top Grossing chart at #39: two people who run ad buying for clients tested their own product first

Voimo (ボイモ, originally 「ボイとれ！」) is a Japanese vocal training app: it first determines which type of singing problem you have, then assigns exercises. It was built by a two-person small company in Edogawa, Tokyo, launched in Jul 14, and released only in Japan. By Nov 6 it had 114 ratings on the App Store yet ranked #39 on the Japan iOS music Top Grossing chart, ahead of the established Voick and Yousician. It made it onto the chart not because the product is so strong, but because the two founders already make their living in this line of work: paid acquisition, store search, and paywalls.

"Came in from an ad"

In Jul 25, a five-star App Store review titled 「ボイトレアプリ始めます！」(I'm starting a vocal training app!) said just one line in the body:

広告から飛んでみたけど、これならボイトレの練習続けられそう！ —— I clicked through from an ad, and with this one I think I can keep up my practice!

This is the only review that openly says where the user came from, and it also reveals the company's background. The developer, テクラル合同会社 (Tekural LLC), is a small company founded in 2022. One of its three listed services on its website is "app ad CPI/CPA optimization": buying app ads for other clients and driving down the cost per install and per payment, across Google, Meta, TikTok, X and YouTube. Its marketing lead, CMO Kento Tajiri, spent about 3 years running app and web ad campaigns at Adways, a listed Japanese ad agency; its CTO, Kensaku Furuse, was the lead engineer at an entertainment startup for 4 years.

Every download button on its website goes through an AppsFlyer tracking link that records sources separately for "homepage" and "which article". That's standard for paid-acquisition firms, not something a typical indie developer sets up first. Where the ads actually ran isn't visible: 11-06 checked Google's Ads Transparency Center and found no ads for it, and nothing matched in the Meta ad library. Apple Search Ads or Instagram are the most likely (inferred).

What it sells

Japanese people who practice singing at home most often search for three things: ミックスボイス (mix voice), 高い声が出ない (can't hit high notes), and 裏声 (falsetto). Voimo's app name packs all of these words in: 「ボイモ | ボイトレ・ミックスボイス・音程・裏声」.

Once opened, it offers 4 courses: mix voice and high notes, pitch accuracy, falsetto, and vibrato. The site says 14 courses, 116 exercises, and "from 5 minutes a day." Each exercise first plays a coach demonstration video, then a "common mistakes" video, and then you sing along while a pitch bar on screen shows whether you hit it (「クリア」 appears when you do). The mix voice course opens with a "voice diagnosis" that sorts your problem into four types: forcing it up (張り上げ), cracking (裏返り), too much breathiness, and failing to blend chest and head voice, then assigns courses by type.

This "diagnose first, then prescribe" pitch is what sets it apart from its peers. Japanese singing apps fall into roughly three groups: pitch-checking tools that show whether you're on key (音程チェッカー, 7,842 ratings); karaoke scoring (うたスマ, 21,213 ratings); and course-based apps (Voick, launched 2020 years ago, 2,981 ratings). Tools tell you whether you sang it right, not what to practice next. Voimo sells the feeling that "a private coach decides what you should practice."

But the diagnosis is actually self-selected. The official description says, in its own words, 「自分の録音とお手本を聴き比べて、近いものを選ぶだけ」(just compare your own recording with the model and pick the closest match). A four-star review from Sep 13 also says: "Choosing and judging your voice type is something you do yourself while listening to the examples; it's not a system or AI that identifies it for you." Another three-star review was blunter: "It can't be personalized; it seems to be just a male and female version."

So the difference is mainly packaging and positioning: it makes the ads and store page convert better and supports the higher prices that follow.

Where the money comes from: payment on day one

Voimo has no free users. The negative reviews make this clear, and the paywall keeps moving earlier:

• Aug 25 (1.1.0 version): "I wanted to practice on day 5 and found out it costs money. I thought it would stay free."
• Aug 29 (1.1.5 version): "Finished lesson 2 on day one, and the subscription popped up when I tried lesson 3. Couldn't continue."
• Oct 2: "Once you finish the tutorial, you can't do anything without paying. I deleted it."
• Oct 5: "They said they'd email a reminder before the one-month trial ends. Not a single email came, and I was just charged."

The two reviews are only 4 days apart, while the paywall moved from day 5 to day 1 (inferred: they were testing where to place it). It updates frequently: Jul 15 1.0.0, and by Nov it was already at 5 1.3.4.

The price tiers are unusually many. The ボイモベーシック product page on the App Store lists 10 prices in total: ¥980, ¥1,480 (two of them), ¥2,480, ¥2,980, ¥7,800, ¥9,800 (two of them), ¥16,800, ¥19,800 (11-06). It looks like five monthly tiers and five annual tiers (my inference; one review says "over 7,000 yen a year is too expensive"), so they're probably testing pricing or running a first-purchase discount. For comparison, in-person voice coaching in Japan is one-on-one: 4 sessions a month runs about 20k yen (musicsound.xsrv.jp surveyed 46 studios, average 22,971 yen). A five-star review in its first week is literally titled "I want voice lessons but I can't afford them."

It also takes payments outside the App Store. The product page shows "外部決済 あり" (external payment available), and the tokushoho (legal disclosure) page on its website says you can subscribe with a Stripe credit card or Apple Pay, with a free trial, and a card pre-authorization happens when you sign up. Money paid through the website doesn't go through the App Store and isn't counted in the grossing chart, so its real revenue may be higher than the chart shows (unverified).

Why 114 ratings is enough to chart

Because the Japan music Top Grossing bar is very low. On the same chart on Nov 5, #25 was a fan-club app for an artist with only 19 ratings, and #27 to #33 were mostly fan-club apps of the same kind. A hard-paywall app with a per-unit price in the thousands of yen only needs a handful of paying users a day to hold its spot.

Its rank keeps bouncing: on 10-28 it was #39, then it swung between #46 and #119, and on 11-06 it was back at #39. Ratings went from 103 to 114 over 9 days, roughly one a day, averaging 4.5 stars. The 4.5 had a head start: in the four days from Jul 15 to 18 it got 7 long four- and five-star reviews ("the best voice app I've used", "I wanted voice lessons but couldn't afford them; this is the best value and saves time"). Negative reviews about the paywall only started in late August. I can't tell whether these early good reviews came from people the team knows.

On App Store search (ASO), it's covering a lot of ground. A wave of similar apps appeared in the Japan store through 2026: Vocalog, うたログ, コエハカリ, ことりボイトレ, SingRise, ボイトレ君, Tonebloom, Sing Boost, ototori… each with 0 to 5 ratings. A new app with 100+ ratings and a 4.5-star average can easily rank above them on these keywords.

Other channels: almost nothing

• Social and media: TikTok searches for 「ボイモ」 and 「ボイとれ」 turn up no related videos; nobody has mentioned it on X in nearly 4 months; press coverage is limited to its own website press release (Aug 23). Shirabe-O (launched Jul 15), which launched around the same time, got coverage on PR TIMES and AppBank, is free, has 26 ratings, and isn't on the charts. Buzz and revenue are two different things here.
• SEO: voimo.net already has 247 「ボイモマガジン」 articles, mostly mass-generated pages: one page per song ("〇〇 音域", e.g. Lemon, 打上花火), one per singer ("〇〇の歌い方"), plus comparison pages like 「ボイトレアプリ 無料」 and 「iPhone ボイトレアプリ」, where it ranks #1 for itself. Spot-checking several head terms, it isn't in the top 10 to 20 results. The domain only switched from voitore.net in October, so this is a long-term bet.
• Android: 100+ downloads on Google Play (11-06), barely worked on.

Has anyone followed it?

One very similar app has. Sing Boost (by OLIVIA 株式会社, listed Oct 24) has store copy that's almost a direct rewrite: 「最初に声と悩みを診断して…専用のレッスンを組み」, and its pain points list "can't hit high notes", "pitch drifts", "voice cracks". As of Nov 6 it still had 0 ratings. Copying the copy is easy; what's hard to copy is the acquisition playbook.

Few people know about it yet: no public revenue figures, nobody talking about it on X or TikTok, and no third-party coverage.

If it were you

In one line: What ボイモ offers you to copy is the method, not the market. The Japanese voice-training niche has gotten a dozen new apps this year, so there's not much room left. What's worth taking is the combination of a "narrow, painful, self-taught need + symptom-based diagnosis + paywall on day one + low-bar category charts", and running it again in another country or another niche.

Who it suits: A team where someone has run app ads and knows the cost of each trial and each paying user, and another person who can produce course content with demo videos within a month or two. Ideally someone who understands a smaller-language market (Korean, German, French, Portuguese), or a craft where people will pay private teachers but struggle to self-learn: spoken pronunciation, posture, a particular instrument, running form.

Who it doesn't suit: People who can't run ads and expect organic store traffic or SEO to drive growth. ボイモ's SEO has been built out over 247 articles and still isn't working, so organic traffic is its weakest link. Also anyone wanting to compete head-on in Japanese voice training: ボイモ, Voick and a dozen new apps are already queued up on the same keywords.

How to do it:

1. Picking a niche: the user's problem can be framed as three or four "symptoms" (like "can't reach high notes", "voice cracks", "breathy tone", "can't sustain"), and in-person private lessons cost tens of thousands of yen or over $100 a month.
2. Product: a set of exercises for each symptom, with real-person demos and "common mistakes" videos. The diagnosis can start as user self-selection, no acoustic model needed. ボイモ does exactly this, and some negative reviews complain about it, but it doesn't stop sales.
3. Pricing: block with a paywall from day one, annual plans with a trial and monthly without, test several price tiers. Send a reminder before the trial ends. ボイモ's one-star reviews are almost all about "didn't know I'd be charged" and "charged without a reminder". In the Japan store you can add external payment (Stripe) to reduce Apple's cut.
4. Store listing: pack the title and subtitle with the most frequent pain-point keywords in that language. In the first week after launch, find ways to collect a batch of genuine long reviews.

How to acquire users: Apple Search Ads to bid on pain-point keywords (inferred to be one of ボイモ's main channels), plus short-form video ads on Meta/Instagram, with creative built around "which of these problems are you having", since the diagnosis itself is the best ad hook. Use a tool like AppsFlyer to track by channel from day one. SEO can run alongside it, but don't expect it to drive volume in the first six months.

Timing: The method itself doesn't go stale, but the window for any single country or niche is short: ボイモ had Sing Boost copying its copy within 3 months of launch. Pick a good opportunity and aim to ship before January 2027, since New Year's resolutions make it the best ad season for singing and language-learning apps (inferred).

Signs you got it wrong: ① ボイモ drops out of the top 150 on the Japan music grossing chart and doesn't recover within a month, meaning the playbook can't survive without the initial ad budget; ② its ratings fall below 4 around 4.5, meaning the reputational cost of the hard paywall outweighs the conversion gains; ③ Sing Boost or another copycat climbs the grossing charts without paid acquisition, meaning the barrier is lower than expected and the differentiation is all in the diagnosis pitch, with the ad craft mattering less; ④ conversely, if you see an app with 0 ratings climb into the top 50 of a category grossing chart within two months on similar keywords in another language, someone in that market is already doing this.