Coconote

A phone app for practicing a foreign language by speaking. The learner talks out loud with an AI tutor in short voice lessons and free role plays, and gets feedback after each attempt. Around that sit a daily word feed, quizzes, verb drills, listening clips and a progress score. Nine languages. The download is free and the lessons need a subscription, listed in the US App Store at US$7.99 or US$8.99 a week or US$29.99 to US$79.99 a year.

The tutor is an AI model, so the company pays for computing and has no teacher to pay by the hour. That allows a yearly price of US$47.99 to US$79.99. Customers came from a very large number of short videos on TikTok and Instagram: first slideshows that the founder's own tool generated and that two people posted from about 12 accounts, then videos by paid creators. Yearly plans are paid in full on the first day, so the cash arrived early. Half of all revenue came in September 2026, and daily sales have fallen since.

An add-in for Microsoft Word, plus a web app, for German-speaking students who write seminar papers and theses. The student uploads the PDFs of the literature. While the student writes, fastwrite suggests the next sentence or a whole paragraph with a citation from those PDFs, and the Tab key accepts it. It also answers questions across all uploaded PDFs with the exact page, searches more than 20 million papers, and checks a draft against nine criteria that universities use for grading.

It puts the AI where German students already write, inside Word and in German, and each suggestion carries a citation from the student's own PDFs, so the student does not have to fear invented sources. A free plan without a time limit brings students in, and a monthly plan sold for the months in which they write turns some of them into paying customers.

An AI study app. A student uploads class materials, such as PDFs, lecture slides, notes, images or YouTube videos, and gets answers with citations to those files, practice questions, flashcards, study guides, audio summaries and a topic-by-topic progress view. It runs on the web and, since May 2026, as an iOS app.

It starts from the student's own course files instead of general knowledge, so answers and practice questions point back to the material that the class uses. A free plan with monthly limits lets students try it, and Pro is sold by the week or by the month. Stripe shows about US$13,200 a month at the end of 2025; the seller says growth came with little to no marketing, and no source explains how students found it.

A calendar that publishes posts to more than 30 social networks: X, LinkedIn, Instagram, TikTok, YouTube, Reddit, Bluesky, Discord and others. The whole code is open source, so anyone can run it on their own server for free; the company sells the hosted version from US$29 a month. Since 2025 AI agents such as Claude, ChatGPT and OpenClaw can connect to it through an MCP server, a command-line tool and a public API, so an agent drafts and schedules the posts and a person approves them in the calendar.

The founder took a twenty-year-old product category with no open-source entry and open-sourced all of it, which gave him millions of Docker downloads and 37,000 GitHub stars without a marketing budget. Revenue stayed small for a year. It multiplied when he turned the product toward people who automate their posting with n8n workflows and, from late 2025, with AI agents, which need an API-first scheduler and keep paying because they post without human effort.

A website and phone app that masters a song from a written request such as "warm, powerful and wide stereo". Each request comes back as a new revision that the user can compare with the earlier ones, and a Spotify link can serve as the reference for loudness and tone. The same subscription includes a splitter that separates a song into vocals, drums, bass and instruments. Since September 2026 the company also offers a generator that makes a music video from the song. Unlimited use costs US$16 a month or US$48 a year on the web.

For its first 20 months the product brought in about US$3,500 a month. Then three things came together: phone apps with weekly plans from August 2025, web plans with unlimited use at US$4 a month billed yearly, and a new group of customers, people who make songs with AI generators such as Suno and need the last step done for them. Monthly revenue rose 7.2 times between January and July 2026. No source states which of the changes caused the rise.

An iPhone app for makeup. The user uploads a selfie without makeup and a photo of a makeup look, for example from TikTok or Instagram. The app's AI applies that look to the user's own face, then gives a step-by-step routine and a list of products to buy. It is free to download and paid for with subscriptions through the App Store.

Its result is a before-and-after picture of the user's own face, which a short video shows in seconds. The founder chose TikTok as the channel before he built the app, then tripled revenue from almost the same installs by moving and testing the paywall with Adapty.

An app for iPhone, Android, Mac, Windows and the web that records meetings, phone calls and lectures, writes a transcript with the speakers identified, and then a summary with action items. A user can also ask questions about a recording. It is free for 30 minutes a month; Pro costs US$100 a year in the app stores.

It reached the App Store early, in July 2023, with the simplest form of the idea: press one button, get a transcript and a summary. The founder paid for Meta ads while they still worked for a new kind of app, tested paywalls constantly and moved buyers to annual plans. He works alone with AI coding tools, so in his own 2026 account about US$3 million of about US$7 million a year stays as profit.

An app for iPhone, Android, Mac, Windows and the web that records speech and returns finished text: a clean note, an email, a list, a social post or a meeting summary split by speaker. A phone keyboard and a desktop dictation tool let users speak into any other app. It handles more than 90 languages and recordings of up to 90 minutes.

The first apps that combined OpenAI's Whisper and ChatGPT for voice notes appeared in 2023, and the founder found them "not implemented well enough". His team built a simpler one, collected early users and feature requests through lifetime deals on AppSumo in 2024, and in 2025 grew with advertising and paywall tests measured in Adapty's subscription data.

An iPhone and Android app that estimates calories, macronutrients and micronutrients from a photo of a meal, with a barcode scanner for packaged food and a log of weight and BMI. It is free to download; the service needs a subscription after a 3-day free trial, at US$9.99 a month or US$49.99 a year in the US store.

One founder released it in August 2025, after Cal AI, released in April 2024, had shown that photo calorie counting sells. It has a hard paywall, a short trial and cheap yearly plans. It appears to have started in France: the French App Store shows 598 ratings against 138 in the US store. The owner lists TikTok as the only marketing channel.

You describe an app in plain language. Base44 generates a working web app with its own database, user login and hosting, so you never touch a server.

It launched in the month that AI models became good enough to write a whole app. It sold to people who cannot program, it charged from day one, and it was sold to a company that already had millions of customers.

A web app for real estate agents and photographers. The agent uploads a photo of a room, chooses the room type and a furniture style, and gets back the same room with furniture in about 10 to 15 seconds. It can also remove existing furniture. Plans are monthly subscriptions sized by the number of photos, and the top plan includes an API.

In 2023, general image generators that were asked to furnish a room also changed the room: the founder said DALL-E might turn a window into a wall painting or add a door, which misrepresents a property. VSAI's own model finds the floor, the ceiling, the mirrors and the doors first and only then adds furniture. It cost US$12 to US$69 a month in early 2024, while VSAI's comparison page lists other staging services at US$16 to US$29 per photo with 12 to 48 hours of waiting. Zillow, the listing portal where such photos end up, bought it.

You photograph your meal. Cal AI sends the picture to a rented AI model and returns an estimate of the calories, protein, carbohydrates and fat. No search, no portion menus.

It sold speed to people who gave up on manual food logging, it paid 250 influencers fixed monthly fees to reach them, and it had a 30-dollar-a-year price. The rented model made the hard part cost almost nothing to build.