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Cosmo is CodeSignal's bite-sized learning app, pitched as Duolingo for job skills. It comes from an established company, the courses are free, and the terms are some of the cleaner ones in this category. Here is who makes it, how it teaches, what Cosmo+ costs, and who it suits.
Editorial note: Iro AI is our app. Where it appears below we say so, and it has to earn its spot by the same criteria as everything else.
Cosmo is a legitimate, well-funded product from a company that has been around for a decade. The courses are free, billing goes through Apple or Google, and its terms are clearer than most of the AI course apps we have reviewed. The trade-offs are breadth and price: AI is one subject among many, and Cosmo+ costs more than most apps in this space.
If you want a light daily habit across several career skills, including coding, it is a reasonable pick. If your goal is specifically to get good at using AI tools at work, a focused app will take you further for less.
Every claim here comes from Cosmo's App Store and Google Play listings, CodeSignal's own pages and Terms of Use (effective August 2025), and VentureBeat's launch coverage. We make a competing app, so weigh our view accordingly. Last reviewed November 2026.
Cosmo is made by CodeSignal, Inc., a Delaware corporation based in San Francisco. It is the same name you see as the seller on the App Store and in the Terms of Use the listing links to, so there is no question about who you are dealing with.
CodeSignal started in 2015 as CodeFights and took its current name in 2018. It is best known for the coding assessments companies use when hiring engineers, and it raised a $50 million Series C led by Index Ventures in 2021. In the app listing, CodeSignal says its platform is used by more than 3,000 employers and more than a million learners.
VentureBeat reported the launch on August 20, 2025, quoting co-founder and CEO Tigran Sloyan, with Android following on August 28. Companies that already pay for CodeSignal's learning platform get Cosmo as part of their subscription. Support is by email at the address on the App Store listing.
Cosmo calls its approach practice first: no videos, a few minutes a day, and an AI tutor that adapts to your level. VentureBeat described lessons that drop you into realistic workplace scenarios, and a tutor you can interrupt with a question at any point, get an explanation, then return to the lesson. The app adds the usual habit tools: streaks, skill badges and shareable certificates.
The range is wide. The listing claims 200+ skills, and launch coverage said 300+ courses, with CodeSignal's own app page using both numbers. Subjects include:
At launch, nearly a third of the content was about generative AI. That is a meaningful share, but it means most of the catalogue is about something else. We did not pay for Cosmo+, so we are not rating the lessons themselves. A fair test in your first week: are you writing and testing prompts yourself, or mostly answering questions about them?
Practice this, don't just read it.
Iro AI turns ideas like the ones in this post into 5-minute exercises with feedback. Free tier, Pro from $4.17 a month ($49.99 a year, 7-day free trial).
Cosmo is free to download, and its App Store listing says every course is free. The limit is energy: practice uses it up, and when it runs out you wait. Cosmo+ is the paid upgrade, and the listing describes it as unlimited energy so you can learn faster.
VentureBeat's launch report put Cosmo+ at $24.99 a month or $149.99 a year, and both prices still appear in the US App Store's in-app purchase list. The same list shows two more options, at $12.99 and $78.00, all four named Unlimited Access, with no label saying what period each covers. They may be offers or different plan lengths; check what the paywall shows you before you tap.
Cosmo+ is sold in the app through Apple or Google. That matters: the store shows the renewal terms at checkout, and you manage or cancel the subscription in your phone's settings.
The App Store listing links to CodeSignal's general Terms of Use, effective August 20, 2025. They do not mention Cosmo by name, but they cover paid services and in-app purchases. The points worth knowing:
The App Store privacy label also says some identifiers may be used to track you across other companies' apps and websites. You can decline when iOS asks to allow tracking.
Compared with the web-sold AI course apps we have covered, such as Skilario, there is no money-back guarantee with conditions to meet and no website checkout to untangle. The trade-off is that CodeSignal offers no guarantee of its own: if you want your money back, it is between you and the store.
Deleting the app does not cancel Cosmo+. Cancel through the store you bought it from:
Apple renews a subscription unless you cancel at least 24 hours before the period ends, so on either platform do it a day or two early. You keep Cosmo+ until the end of the period, and the free courses stay available after that.
Before you pay, use the free courses for a week. If the energy limit is the only thing in your way, Cosmo+ is a simple purchase to undo. Our guide to spotting an AI subscription trap covers the checks worth making with any learning app.
Iro AI is our app, so weigh this accordingly. Where Cosmo covers 200+ skills, Iro covers one: using AI well. That focus is the point. You write real prompts in the Prompt Lab and get them scored, learn to spot AI mistakes and hallucinations, and keep the habit going with streaks, ranks and timed duels against a skill-matched opponent.
On price: Iro is free to start, with a battery that gives you a full lesson every day and recharges overnight, much like Cosmo's energy. Pro is $9.99 a month or $49.99 a year, the annual plan includes a 7-day free trial, and it is billed by Apple, so cancelling is the same two taps in Settings. That is less than half of Cosmo+'s $24.99 monthly price and a third of its $149.99 yearly one.
For scale: 34 learning paths, 522 lessons and 3,000+ exercises across 23 exercise types, covering ChatGPT, Claude, Gemini, Perplexity, prompting, agents and automation, with every path open on the free tier. One honest limit: Iro is on iPhone today, and Android is still in development. See exactly what the free tier includes, or take the two-minute AI rank quiz first.
Practice this, don't just read it.
Iro AI turns ideas like the ones in this post into 5-minute exercises with feedback. Free tier, Pro from $4.17 a month ($49.99 a year, 7-day free trial).
Yes. Cosmo is made by CodeSignal, Inc., a San Francisco company founded in 2015 and best known for its technical hiring assessments. It is sold through the App Store and Google Play, and the App Store listing names CodeSignal as the seller.
The courses are free, and the App Store listing says so. Practice uses energy, and when it runs out you wait. Cosmo+ is the paid upgrade that gives you unlimited energy.
VentureBeat's launch coverage priced Cosmo+ at $24.99 a month or $149.99 a year, and both prices still appear on the US App Store. The listing also shows $12.99 and $78.00 options without saying what period they cover, so check the paywall before you buy.
Cosmo is bought through Apple or Google, so ask the store you paid. CodeSignal's terms say it does not give refunds for paid services unless local law requires one, as it does for 14 days in many European countries and the UK.
On iPhone, go to Settings, tap your name, then Subscriptions, then Cosmo. On Android, open the Play Store, tap your profile, then Payments & subscriptions. On iPhone, cancel at least 24 hours before the renewal date. Deleting the app does not cancel it.
It covers GenAI, including prompting and using ChatGPT at work, but AI is roughly a third of a catalogue that also spans business, coding and data. If AI skills are your main goal, a focused app such as Iro AI goes deeper on that one subject.