Freemium is a business model in which a company gives a basic version of its product away and charges for a paid version with more features or capacity. The free tier works as the marketing budget: it brings users in at little cost, and a small share of them pay for everyone else.
RewiredAI rewires it: a free user who uses AI features costs real money, so the AI moves into a premium tier and the arithmetic of giving the product away changes.
How it makes money
Freemium is a bet on arithmetic. Give the product to everyone, make it good enough that people stay, and let a minority pay for the rest. The bet pays when serving another free user costs close to nothing, because then the free tier is cheap advertising and every upgrade is nearly all margin.
In business model terms, the user and the payer have come apart: most users pay nothing, and the price falls on the few who want more. AI tests the cost side of that split. A lesson served from a database is cheap to repeat. A conversation with an AI tutor costs computing power every time it runs, whether or not the user pays.
The model at full scale
Duolingo is the plainest public case. Its 10-K calls the freemium model, "allowing users to access our content for free and charging a subscription for additional features," core to its success "because it enables significant user scale." Every course is free. At December 31, 2025, about 9% of its monthly active users were paid subscribers. The other users are the audience the paying ones are drawn from.
Where the AI went
Duolingo did not put its generative AI in the free tier. Duolingo Max, launched in 2023 and "powered by GenAI technology," is a premium tier "priced higher than Super Duolingo," the existing paid plan. The model gained a third floor: free at the bottom, paid in the middle, AI on top.
The cost showed up in the margin. Total gross margin fell to 72.2% in 2025 from 72.8% in 2024, which the company put down partly to "increased AI costs used in features like Video Call" and partly to a shift toward advertising revenue, which earns less than subscriptions. It then recovered: 72.8% in the first half of 2026, against 71.8% a year earlier.
How it fails
Freemium fails when the free tier gets expensive and the upgrade does not get more attractive. A free plan that ran AI for every user would turn the marketing budget into a cost that rises with each person who never pays. Duolingo's filing shows the pressure at small scale: AI features that cost money each time they run, and a revenue mix moving toward lower-margin advertising.
Our read
AI does not end freemium. It moves the line between free and paid. The free tier used to be generous because generosity was cheap. Now generosity has a cost per use, so the AI goes behind the paywall, or into a tier above it, and the free plan keeps the parts that cost nothing to repeat.
For a seller, the test is easy to state and hard to pass: what does a free user cost this year, with AI, against what they cost before? If that number moved, the conversion rate that used to justify the free tier may no longer cover it. For a buyer, expect the best AI features to sit a floor above the plan you already pay for, and expect the free plan to get AI in rations.
Questions
- What is a freemium business model?
- A model in which the basic product is free and a paid version, with more features or capacity, earns the money. Duolingo makes every course free and charges a subscription for extra features; about 9% of its monthly active users paid at the end of 2025.
- How does AI change freemium economics?
- AI features cost computing power each time they run, so a free user is no longer nearly free to serve. Duolingo put its GenAI features in Duolingo Max, a tier priced above its existing paid plan, and named AI costs as a reason its 2025 gross margin slipped.
- Should AI features be free or paid?
- Features that cost little to run can stay free and help bring users in. Features whose cost rises with use are usually safer in a paid tier, or rationed on the free plan, so the people who use them most are the ones who pay for them.
Sources
- Duolingo, Inc. (SEC EDGAR), Form 10-K for 2025 (2026-02-27)
- Duolingo, Inc. (SEC EDGAR), Form 10-Q for the quarter ended June 30, 2026 (2026-08-06)
Every figure and quotation on this page traces to these filings. “Our read” is Stratrix’s judgment, drawn from them. Analysis and data, not advice.
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