A reverse-audio app that entered a year late: a Vietnamese developer grabbed traffic in Latin America and the Middle East just by changing one word

Vietnamese indie dev Duc Duong Tran launched Reverse Voice: AI Changer in 2026 August, a "reverse singing" app, a full year after the category took off. There are already 30+ competitors, yet it has carved out a slice of the tool category charts in Mexico, Indonesia and Saudi Arabia: 706 new ratings in the last 7 days, and its share among the top players rose from 8.6% to 15.3% in two weeks. It has no new mechanic. It wins on a search term competitors left open, 17 languages, and ad creatives that look like paid acquisition. Below: how it got going, how much money it makes, and whether you should get in.

A 21.1M-view video left a search term behind

On 2025 August 19, TikTok user @fullmhouse posted a video of a person singing a line, the app playing it backwards, another person copying the reversed weird sound, and then reversing that recording back to compare with the original song. The caption was just: "App is called Reverse audio 🤣". By Nov 6 it had 21.1M views. Three days earlier, @marceeeee_l in Mexico posted a couple's version that got 7.96M views.

What followed is easy to guess: the "reverse singing challenge" (Reto cantando al revés in Spanish) spread, people searched "reverse audio" in the App Store, and a wave of clones launched from 2025 August through December. The heat hasn't fully faded: in 2026 September a reverse-singing challenge in Mexico hit 1.37M views; in Oct 18 and Nov 3, a Brazilian account posted two videos captioned "O nome do app é reverse audio" ("the app's name is reverse audio") with 650k and 710k views (TikTok, 11-06).

So this is a demand that someone has already educated people about: viewers see the video and know what to search for.

What it is

The store page is blunt: record or import audio, play it backwards, adjust speed and pitch, trim clips, save and share. A few extras were added: AI voice changing ("AI Voice Cover", requires internet), flipping images left-right or top-bottom, and some "reversed video" inspiration examples.

Monetization is a hard paywall: the app is free to download, but reversing, image flipping and AI voice changing all require a subscription to "Voice Reverser Pro" at $4.99 per week, possibly with a trial (App Store page, 11-06). In other words, if you pay nothing, the app is basically unusable.

The developer account has 13 apps in total: PDF readers, file recovery, QR scanners, plant identification, cleaner tools, homework helpers, tarot readings, gemstone identification... Most were batch-released in the first half of 2026, with single-digit or zero ratings. Reverse Voice is the only one that has gained traction (App Store, 11-06). This is a classic "template factory": one person keeps shipping new apps on the same shell, and doubles down on whichever one takes off.

How big it is now

Third-party data site AppGazers estimates October downloads of 108k to 488k and in-app purchase revenue under $5,000 (a model estimate, not public data). AppInsider recorded its best showing in Saudi Arabia's overall Top Free chart as #12.

The downloads have arrived, but the money hasn't clearly followed. Reviews show it: nearly all recent negative reviews say the same thing. Mexico: "This app is so greedy, you have to pay to play a reversed audio clip?" Turkey: "Para istiyor" (it wants money). Spain: "Vale dinero" (it costs money). A Saudi and a Turkish review each just say "bad".

A crowded category, and how it squeezed in

First, the competition (ratings are combined across App Store storefronts, 11-06):

The top three add 1 to 3 times as many ratings per day as it does. It isn't first, but it is the only app among the 2026-launched clones that has gained real traction. A few things combined:

A different word. Most rivals are called "Reverse Audio" or "Reverse Singing"; it's called "Reverse Voice". In Nov 6, searching "reverse voice" in the App Store placed it #3 in the US store and #2 in Mexico; searching "voice reverser" placed it #2 in both. The main term was locked up by early players, so it named itself after a synonym that still had room.

17 languages, targeting small markets. Arabic, Turkish, Indonesian, Spanish, Thai and Vietnamese are all covered. In countries like Uruguay, Guatemala, Costa Rica, Bahrain and Kuwait, the Utilities Top Free bar is low: a few dozen ratings can land you in the top 10. Charting in a category also adds a second stream of browse traffic. Its volume was built country by country.

Likely paid acquisition. On Facebook, a page under a fake-looking name, "Squires Woodarduolm", posted two videos on Oct 2 and 4 titled "Reverse Voice AI Changer", with the copy "Try the reverse singing challenge with instant playback, pitch and speed controls." They show 47k and 119k views but only single-digit comments. A page with a fake-looking name, high views and almost no engagement is typical of ad spend (inference). On TikTok, a Vietnamese account, @ai_reverse_audio, has posted 1,619 videos and has only 2,147 followers; on Oct 26 it batch-posted 10 videos titled "Make Friends Laugh Today", and the video data carries paid-promotion markers. The names and the developer's nationality line up, but the videos don't directly link to this app, so whether it's the same operation can't be confirmed.

Riding the wave. In late October the whole category picked up at once: Reto Cantar's daily new ratings rose from 70 to 348, and the original Reverse Audio rose from 53 to 197. Whether this was the holiday season, another round of creator videos in Latin America and Brazil, or several apps increasing spend at once, can't be seen from outside. Its share is rising, but only because the whole pot is hot.

The AI voice feature isn't the reason. No negative review mentions AI voice changing, and none of the positive ones do either. Users come for the reverse-challenge itself. AI voice changing looks more like the justification for a $4.99-per-week price.

How many are chasing it

Plenty. The category was already crowded, and in 2026 9 and October new apps kept launching: "Reverse Audio · Voice Changer" (9-22), "Reverse Audio & Reverse Voice" (10-09), "Al Revés" (10-28)... Names have started to include "Reverse Voice" and "Voice Changer", apparently chasing its keywords, but none of them have volume yet.

Surprisingly few people know about it: no media coverage, no one mentioned it on X in 60 days, the developer hasn't shared any revenue, and only a few auto-scraping sites have pages for it.

If it were you

Grade C: you can learn a playbook, but following this category isn't worth much. The reverse-singing challenge was a TikTok trend a year ago. The top three already add over a thousand ratings a day, there are more than thirty clones behind them, and estimated revenue is currently only a few thousand dollars a month. It gets its traffic from a secondary keyword and small-country charts, and those spots are hard to win a share of now. What's worth taking away is the method, not this app.

Who it suits: individuals or small teams already batch-making template apps, who have ready-made shells, can write store pages in 17 languages, and can run small-budget creative on Meta and TikTok, and who want to try one more direction where "the search term is already educated".

Who it doesn't suit: anyone wanting to build a long-term business on one product (it's one-off entertainment with naturally weak retention, and interest rises and falls with TikTok); anyone aiming at the big English market (even in the US store it sits around #170); anyone unwilling to use a weekly subscription hard paywall (this category's money comes largely from impulse subscribers who forget to cancel; switching to a one-time purchase would very likely earn less, inference).

How to do it: don't build the 31th reversing app. Apply its playbook to the next small tool mechanic a TikTok trend pushes: the moment someone in a trend video says "the app is called ××" is when a search term is born. Watch for these videos, see which term the top apps have taken and which synonym is still open, and name your app with that one. Localize into every language from day one and go after Latin American, Middle Eastern and Southeast Asian Top Charts first. You can copy the paywall, but price it for what Latin American users will accept: $4.99 a week in those markets brings one-star reviews.

How to get users: store search is the main channel, and the name is the keyword. Support it with small-budget ads: a vertical demo video, "here's how to play this challenge," using the challenge's own wording ("try singing it backwards"), targeted by country on Meta and TikTok. At the same time, find creators doing the challenge on TikTok in Spanish, Portuguese and Arabic, and get them to say your app's name in their videos.

When the window is: for this category itself, the window has largely closed, and nobody can say when the late-October revival will fade. For the next similar trend, the window is the first few weeks after the trend video appears: within a month of @fullmhouse's video, the first clones had launched.

Signs that would mean you read it wrong:

• Its daily new ratings fall back to a few dozen by late November and its share stops rising: this means it simply rode the category's revival or a single spend burst, and the method itself didn't work;
• It charts in the Top Grossing list of some country: this means the category's money is bigger than estimated, and it's worth re-checking (at that point the grade should probably be raised);
• A new app with the same name (the "Reverse Audio & Reverse Voice" batch) pushes it out of the top three for "reverse voice" search within a few weeks: this means the secondary-keyword position can't be held, and the playbook's dividend lasts only a few months.

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Data and sources: App Store storefront charts, ratings and reviews (10-28 to 11-06), store pages and search results (11-06); public videos and view counts from TikTok @fullmhouse, @marceeeee_l, @canal.angil, @ai_reverse_audio (11-06); the video page of the Facebook page "Squires Woodarduolm" (11-06); estimate pages from AppGazers and AppInsider. Revenue figures are third-party estimates, not public data.