A TikTok with 5.5M views, and a WhatsApp sticker number that gets rid of the white border

Felku is a Brazilian sticker app that launched four weeks ago on Google Play with just over 10,000 installs. On its own it's not much to learn from. What's worth looking at is what sits in front of it: a WhatsApp number. You send it a photo, and it sends back a cut-out sticker with no white border. A Brazilian indie developer, posting on TikTok himself, pushed that number in front of (by his own account) 430k people. Below I lay out what it is, where the traffic came from, how it makes money, who it competes with, and which part you can take away.

A single post, 639k likes

On 2026 Apr 4, TikTok user @upaulinhoo posted a photo post with the caption:

Chega de ficar sem figurinhas de memes, brincadeiras, artistas e famílias. Agora você envia uma foto ou vídeo e essa automação transforma em figurinha — Link no meu perfil

"Stop missing meme stickers. Now send a photo or video and this automation turns it into a sticker. Link is in my profile." The tags were #virginia #neymar #patixa, the hottest influencers, footballers and memes in Brazil at the time. By Nov 6, the post had 5.5M views, 639k likes and 13.8k shares (TikTok data, 11-06).

The account belongs to Paulo Henrique Reis Alves, who is registered as a sole proprietor in Brazil, and Felku is his one-person product. The account has only 1,984 followers today but has collected 655k likes, almost all from this one post.

The comments say more than the video itself. The three most-liked:

odeio as figurinhas do WhatsApp que sai com a borda branca (63k likes) "I hate that WhatsApp stickers come out with a white border."

agr o mico ter figurinha com a borda branca (59k likes) "Now it's embarrassing to still have stickers with a white border."

Further down there's a string of "FUNCIONAA" and "funciona msm" ("it actually works"), plus one comment, "NÃO TEM BORDA DE CATUPIRY" ("no Catupiry border"). Brazilians call the white outline WhatsApp's automatic cutout adds the "Catupiry border," comparing it to the ring of cheese on a pizza crust.

What it is: a contact, not an app

There's only one step: save +55 11 97877-5451 to your contacts, then send it photos, GIFs, short videos, or links from TikTok, X or Pinterest. A few seconds later it sends back a sticker you can long-press to save. If the photo has a caption, the sticker carries that text; videos are trimmed to their first 10 seconds and turned into animated stickers (official guide page, 11-06).

It has one selling point: the white border. WhatsApp has included a built-in sticker editor since 2024. It's free, but the cutouts it makes automatically get a white outline, and it can't take videos or links. In Brazil, where hundreds of millions of people chat with stickers in groups every day, that border is a small annoyance everyone has run into and no one has solved. The dozens of videos he posted later all narrowed their hook to this one line: "figurinha sem borda branca" (a sticker without a white border).

The Android app, launched 9 Oct, came later. It makes stickers and manages sticker packs, and it bundles two extras: a Místico astrology birth-chart generator (outputs a PDF) and a habit tracker. The official site homepage now says "three small things that fit into your day," and also has a "Baixador Felku" that downloads videos from X, TikTok and Kuaishou Brazil, used as a traffic funnel.

Where the volume comes from

The founder films it himself. After the hit, he kept posting from the same template: 21 videos in June, 18 in July. The approach is fixed: show a finished sticker, ride the trending figure of the week's tags (Virginia, Neymar, Gretchen, Dua Lipa; in September it switched to banker Vorcaro, who was in the news), and close with "link do bot no meu perfil" (bot link in my profile). Only that one post went viral. Of the posts that passed 100k views, one has 6-11 (266k) and another has 8-13 (176k); most have only a few thousand.

Users don't have to install anything. This is why conversion is fast: see the video, tap the profile, tap the wa.me link, chat opens in WhatsApp, and the first sticker is already back. No app store, no sign-up in between.

SEO pages, not in use yet. felku.com.br has 18 guides in Portuguese, English and Spanish, about 51 URLs total, covering holiday-keyword pages (Halloween, Christmas, Black Friday, New Year stickers) and a post titled "2026 Best Sticker Bots" written for the users of NekoMoji, which shut down in Sep 30. But search "bot de figurinha whatsapp" or "como fazer figurinha no whatsapp" in the Brazil store and Felku isn't in the top 10 results (11-06).

An Instagram sticker account @figurinhas_whatsapp has, from the start of the year through May, repeatedly posted the "save Felku to your contacts" copy. Probably theirs (inferred).

Ads: none seen. Nothing turned up in the Meta Ad Library, but paid promotion can't be ruled out.

Self-reported reach keeps climbing: the old landing site stickerzap.com.br says "+187k users", the X bio says "+400k", and the homepage now says "430k people use it, 4M stickers made". All self-reported, can't be verified.

How it makes money

New Brazilian users get one free sticker, a single time, with no daily reset. After that you buy sticker packs inside the chat and pay on the spot. No subscription. The guide page spells out the reasoning plainly:

Every sticker bot has costs to run: servers, video conversion, and WhatsApp's messaging fees.

Pack prices only show up inside the chat, not on the website. The app's in-app purchase range is $1.59–$19.99 (Google Play, 11-06), and from the outside you can't tell whether it sells sticker packs or horoscope readings. Conversion and revenue aren't public.

Pay-per-use suits this category. Making stickers happens in bursts: a meme blows up, you make five, then you don't touch it for a month. A subscription wouldn't keep people.

The app: in a red ocean, already sliding

(Early figures are third-party estimates; the November figure is Google Play data.)

On the Brazil Personalization free chart, it fell from #10-29 on 139 to #11-06 on 196. No ratings, no reviews, and the version has stayed at 1.1.1. The likeliest source is bot and website users being pushed over to the app, not organic store traffic (inferred). The habit tracker only exists in the app, which looks built to pull people into installing it.

The app competes with Sticker.ly (342M installs, still adding about +488k in the last 7 days) and a crowd of sticker-making apps with 40M to 200M installs each. It has no edge there. Its real selling point is "no app install needed."

Who it's competing with

"Sticker bots inside WhatsApp" has been a small category in Brazil for a while, with several players. Felku's product differs from them only slightly. What sets it apart is that its founder makes short videos on camera, and one of them went viral. NekoMoji's fate is worth noting too: one person couldn't carry the server and messaging costs or the workload, so it shut down.

If it were you

B. Worth a test, but what you should copy is the playbook of "turn the tool into a chat number + make short videos yourself", not Brazilian stickers as such. Brazil already has seven or eight sticker bots, and the app route is an even redder ocean. The opening is in markets where WhatsApp, LINE or Telegram are deeply embedded and nobody has done this yet.

Who it's for: 1 people who can work with the WhatsApp Business API or a Telegram Bot. The target is a market whose mother tongue is heavy IM sticker use (Indonesia, Mexico, Argentina, India, Turkey, Thailand, where LINE is used), and who will appear on camera or edit their own clips, putting out ten-plus short videos a week.

Who it's not for: people counting on store organic traffic or SEO to get going (Felku's own app and 51 guide pages show that's slow). People unwilling to make content. People who haven't worked out the messaging and compute cost per sticker and are betting that a free quota will hook users first (that's how NekoMoji closed).

How to do it: one number, one thing done best. First find one concrete flaw in the built-in feature of your market's messaging app (white borders, no animated stickers, no links, ugly fonts), then build the whole product around fixing it. Free first sticker, then pay per pack, no subscription. Don't rush to build an app, and definitely don't stuff in horoscopes or habit tracking.

How to get users: copy Felku's template. A vertical video showing a finished sticker that happens to be this week's trending person or meme, with the caption pointing straight at the flaw ("no white border"), ending with "the number is in my bio." Swap the hashtags for whatever is trending in your country that week. One hit is enough to grow, so you need to post a lot. The comments asking "does it really work?" and "can it make animated ones?" are your next video topics.

When to start: launch before December, to catch the peak of Christmas, New Year and year-end memes. Felku itself set up its Christmas and New Year sticker pages early.

What would mean we got it wrong: ① your market's WhatsApp or LINE built-in editor drops the white borders or adds video-to-sticker, and the hook is gone; ② Meta changes WhatsApp Business API pricing or limits bot auto-replies, pushing per-sticker cost above your price; ③ you post 30+ videos and none passes 100k views. This playbook runs on hits, and without hits it doesn't work; ④ the reverse: Felku's Android app climbs back above a thousand installs a day in December and starts collecting ratings. That would show the app route works and we underrated it.