How I Built This $160K/Month Gym App

0:00I launched Symmetry a year ago, and now it's one of the biggest names in one of the most saturated app markets. This is Mauro. He's 22, and in just 1 year, he built an app that makes over $160,000 a month. But, this isn't really a story about the app he built. It's more of a story about how he decides what to

0:20build. First, we built what we [music] wanted, terrible idea. Second, we built what users wanted, mediocre. And now we approach a methodical and scientific way of actually building useful things. Most builders just ship features and hope they work, but Mauro does it differently. He treats every feature like a scientific experiment, and I think it's the number one reason his app

0:42is so successful. Adding one screen, it's increased 3% retention. That is why you have to AB test everything. So, I asked Mauro to come on to the channel to break down this entire approach. In this episode, we'll dive into the app that he built that makes over $160,000 a month, why most builders are wasting so much time on features that won't move the needle, and his approach on how to build apps the right

1:06way in 2026. All right, let's dive in. I'm Pat Walls, and this is Starter Story. All right, Mauro, Gus and I would love to welcome you to the Starter Story channel. So, tell us about who you are, what app you built, and what's your story. So, my name is Mauro. I'm 22 years old, and I like to gym so much that I built Symmetry, the fastest growing fitness app in the Spanish market. I launched Symmetry like a year ago, and now it's one of the biggest names in one of the most saturated app markets. And today, I want to share all the tactics of how I

1:36did it. All right, Mauro, uh thanks for being here. Could you just pull up your app, tell us what it is, who your users are, and then pull up your revenue dashboard to show off that this is legit. Okay, so basically, it's a gym tracking app. So, you can track your workouts and track your weight and reps for different exercises. And currently, we are in the Spanish markets, mainly in Spain and Mexico. Okay, so this is our revenue cut dashboard. You can see we're currently at around 160k monthly revenue. And we currently have around 3 million

2:04downloads both across iOS and Android. But what I think is super cool about what you built is that you built this gym app, but it's sort of localized to the LATAM market, the Spanish market. There's plenty of gym apps in the US, and then finding this sort of niche. This is clearly working. It's doing over $160,000 in revenue in the last 30 days, which is cool. And we're going to talk all about the growth, but before we do, I want to understand a little bit about your background. Had you always been

2:29building apps? What's your background? How did you get to this point? Growing up, I was actually obese, and the gym is what helped me a lot. The reason I built Symmetry was to share this improvement I had in my life with others. Before building Symmetry, I was actually a fitness YouTuber, and so were my co-founders. And we were like, "Okay, YouTube is good, but we want to help more people. How can we do this?" And that is when we joined together to build

2:51Symmetry. All right, before we get into some of the stuff we want to talk about when it comes to like building the product, let's talk about growth. So, maybe just give us a little bit of a sense of your growth timeline. You said you launched like a year ago. Talk to us about your

3:03growth timeline in the last year. So, we launched on 6th of June of last year, so just barely over a year. When we first launched, we had a very small spike in downloads due to our previous YouTuber era, but then we had to transform into another acquisition channel that was reliable and scalable. And over summer, we were trying to do UGC. We barely were at around 30k downloads. At the end of quarter four, we did see a slight increase, but it was

3:26in January, in Q1, when we saw a spike. Maybe people go to the gym more in January. And since then, we've stabilized. Awesome. And then let's talk about some of the tactics that you used to grow. I think you just mentioned UGC. What were some of the main growth strategies you used to grow this app to over $150,000 a

3:43month? So, first when we launched, we had this YouTube community. And we thought it was going to be really good for growing the app. It wasn't. So, we started to try new things. We went into influencer marketing. Well, it didn't work. So, we tried other methods and that is when we found GC. We were really good at it and we just did more and better. Okay, so this is our internal dashboard. In the last year, we have posted nearly 80,000 videos. We have more than 500 accounts and we have done nearly 8 billion views in the last year. Something that really works for us is we segment the videos

4:15into formats. This was a format that works really good for us where you see the lock screen of your iPhone with a notification. In this case, your girlfriend like leaving you and below a symmetry notification saying, "Go to the gym and workout." Well, it works so well that we track all of the videos and we even have sub formats to segment them even more. And this video went extremely viral. You can see 17 million views. So, the way we pay our creators and how much are we spending on marketing? Basically, we give nearly half of the revenue to

4:39the creators. So, we pay them a lot. This way they are incentivized to do more content and to stay in symmetry for the long run. Okay, thanks for sharing all that about how you grew. I think it's super cool. We've done a ton of videos on UGC. I don't think that's anything new and you can go and check out a bunch of the content that they create and and see some of the examples. But I actually thought was super cool and we had chatted before, Mauro, is you told me you have like sort of like a different approach to building. And when we started digging into it, I thought it

5:06was super cool because you got this app to $160,000 a month within 1 year and that's like really, really fast. Like usually you'll see, you know, maybe get to 30 or 50K within a year. You did it super fast and I think one of those reasons was sort of you have this sort of different approach to building that you shared with me where things just kind of started working right away. So, could you share with me that approach to like how you knew what to build, what features to

5:31build? Yeah, so we went through three different phases when building Symmetry. First, we built what we wanted. Terrible idea. Second, we built what users wanted like directly from feedback quest. Mediocre. And now we approach a methodical and scientific way of actually building useful things. Okay, yeah, so I agree. I mean, I see a lot of people that go and just start building stuff. Maybe they ask their AI tool about what to build, or maybe they build based on instincts. But yeah, yours is a little different. Could you dive a little bit more into what you

6:01mean by that? Yeah, so people normally are incorrect about what is important to build and what is not important. [music] Let's say you build a dark theme or a light theme. This may affect like 2% of your daily active users. Whereas, if you AB test the paywall, it's going to affect a lot of users in a radical way. That's why there are like even softwares just to AB test on screen. And apart from the paywall, there are very other important places of your app, and your job is to find those places and AB test them and really exploit all of the metrics from them. For example, in symmetry our

6:28exercise search screen, so the screen you search exercises has a huge impact on activation and retention. Whereas, the screen you log into the app first to see your workouts, we've done a lot of things there and doesn't seem to change anything. Hey, it's Gus, producer here at Starter Story. I love everything that Maro is breaking down about his process of building apps. I hope you're watching this and getting excited about building your own app as well. But, if you're still looking for an idea, we have just [music] the thing for you. It's our free iOS database, and inside you will find hundreds of proven app ideas, and many

6:59of them are making over $10,000 a month. And each of the ideas in the database has the numbers to back it up. Real revenue, pricing models, growth tactics, basically everything you need to validate whether this is a good idea or not. Just head to the link in the description and grab this database. [music] It's 100% for free. All right,

7:16let's get back to the episode. Okay, so you kind of approach the features to work on or to improve on like what most people are using instead of focusing on maybe like more edge cases. Tell me a little bit more about how you track that sort of thing and like how someone watching this could

7:32potentially do the same. So, first you want to decide what metrics to actually move. For me, I use quarterly OKRs, and put really ambitious OKRs. If your app is really new, put ambitious OKRs. Like, it's very easy to increase 10% conversion rate in 90 days if your app was launched last week. Whereas, if you're Netflix, it's not going to be as easy. So, the earlier the product is, the more ambitious your OKRs have to be. For example, in our case, we call this thing a warm-up, which we do every 90 days because we're going to war. Here you have your marketing objectives, your product, and then here

8:01we have all of the metrics to keep track, and we see them if not weekly, daily, to make sure we are always on track towards these OKRs. OKRs are very important to give you direction and to know towards where to build. For a gym tracking app, a very important metric is activation. If you move activation, retention follows. For example, activation in symmetry is really hard because you have to make someone go to the gym and actually track the workout, which is crazy friction, even both for a beginner that has never gone to a gym, or someone at the end that you have to change his behavior, his pattern of

8:31working out. Crazy work. Whereas, for example, in a calorie tracking app, you just snap a photo, and that's activation. So, you must know which metrics you want to move, and which ones are going to bring long-term revenue. Okay, cool. I mean, having OKRs that your team can go towards and know if I I built this feature, it made this number go up, or I built that feature, then you

8:49have actual data that you can verify. I'm curious, though, like, for people watching this that are also building apps, what are like the key data points that you are tracking? Well, first of all, especially if you're new, downloads. Like, the more downloads, the more revenues, it's proportional. So, that's very important. Regarding more to the product, depends on your product. Activation, in our case, is very important, but for most apps, yes, like, first week retention or

9:1230-day retentions are very important. And also very important number is ARPU, average revenue per user. How much you make for every download. This is going to basically decide the amount of money you can pay for creators if they bring downloads. And ARPU varies a lot between countries. So, you must track this in a

9:27very methodical way. I think a lot of people watching this are also building something. They're building an app, maybe they even have a live app in the App Store, or they have a SaaS uh, internet. I think this framework is really cool where you're actually using data and then making decisions based on that data. Could you give some advice to people who are watching this right now who want to implement a system like this? What data should they be tracking? How should they be running experiments? And what would you do if you're just getting started

9:52right now? Well, first, the the most common error I see everybody is not tracking anything. Like, they don't have any events at all in their app. And then like, "Okay, what's your drop off here?" And they're like, "Um, I don't know." Well, you must have analytics put in your app. Remember, the earlier they are in the funnel, the more in detail they should be. So, onboarding must be tracked every screen. This analytics are very good for quantitative data. Meaning, you know where you're losing people. So, that tells you where the problem is happening, but not the why. For the why, you need qualitative data. Here you

10:21speak with the users, or they maybe put up posts in like a Discord or a Reddit about your app, something like that. And then you understand why something is happening. So, you know the what is happening due to the funnels and the beta analytics. [music] And then you know the why because you speak with the users. Yeah, this is something super common that I see people who are like developers, they're like, uh, want to just get only qualitative data. And then they end up like like sending a bunch of surveys and not actually like talking to customers. And there's so much value you can get out of talking to customers. The

10:53last question that I sort of have around this is around, okay, so when you need to make a product decision, how do you go about AB testing two different things? How do you track that? How do you think about it? Okay, first, you're not coming from a solution place. You must come from a problem space. So, coming up with problems. And then after you go for the solution. Here you come up with different hypotheses, different solutions, and you design experiments to test this hypothesis. So, first, what problem am I solving? How do I know if it's real? You must know if it's This is happening. And then what's the solution

11:23and the hypothesis? How much will each hypothesis move the metric? Are there any guardrail metrics I should watch out? And then also very important, you must AB test everything. You have your control version, the version of your app currently, and the new version being AB tested. And after at least 2 weeks of running the experiment, you then analyze the data and really know what is happening to the users. For example, this is what we call Evelyn, experiment

11:44velocity engine listing your numbers. Here we have all of our AB test tracks. This is a database that comes from user interviews. So, it's user interviews that show us that user problem. Then we do the hypothesis, and then we do the experiment. These experiments are being tracked in Posthog. So, here we track everything, and we can see how everything is running. For example, this was an experiment I mentioned earlier about the page you see after the

12:05onboarding, where you see your workouts. You see here we tested two different variants apart from the control, and they moved nothing the metrics, absolutely nothing. And they were completely different designs. This tells us, "Hey, let's not focus on here again. This is an inconclusive test. Let's focus on other areas of the app." For example, this experiment is just one screen at the end of the onboarding, where you commit to like workout. So, like you're like signing, "Hey, I'm going to workout." That's it, one screen. Let's look at how the the metrics moved. It increased 3% retention adding one screen. That is why you have

12:34to AB test everything. Yeah, I was just going to chime in with a quick thought, which was like I didn't start building anything until all these AI coding tools came out, and I definitely fall into the trap of like, "Oh, that would be cool. That'd be cool if it existed." Without any information. And so, you listening to you talk here, I'm like, "Okay, there's a lot of good things to keep in mind." Cool, let's switch topics a little bit. Uh so, you you talked us about all the things you analyze and all the tools you use. Maybe just walk us through the tech stack you've used to to build this app or the

13:00tech stack and tools you use on a daily basis to to run this app. Well, obviously I use me and my team we use Cloud everywhere. We love to use Cloud with MCPs, and we connect to this analytics tool like Posthog or Superwall or RevenueCat with MCP, and see all of our data from there. I also use WhisperFlow a lot. I like to speak with my computer, and that way I'm I'm faster than typing. Also, for AB testing the paywalls, we use Superwall. They have really good experimentation tools. For AB testing, we use Posthog. Then we use Notion to track all of our documentation and Slack to speak with the team and

13:31that's pretty much it. Okay, thanks for sharing tech stack. I'm also curious. We've been talking all about your app here. Could you just give me a quick demo of your app that makes over $160,000 a month? Yeah, so our app we try to make it really simple. So the first thing you see when you come is just like your plan to work out. You click on the plan and you see a workout preview and then you start your workout. Here you can track your weights, your reps and we even have like videos to explain [music] different exercises. And then the thing that

13:59people most like is here the ranks. You're seeing the ranks page where you have a rank for every muscle group and for every exercise. And also here you have the social network. So it's like a Strava. You can see here all of the people in in the feed uploading their workouts. [music] I even have my own workouts here. So it's really fun because people share

14:13their workouts. You have your streak. You cannot lose your streak to your friends. You can level up in different exercises and people just are having a really good time in Symmetry. Okay, thanks for sharing. Looks like an awesome app. Last question that we ask all founders to come on to Starter Story. If you could go back in time before the year that you started Symmetry, before you had a successful app, what would be your advice to your younger self or for anyone watching this that wants to build apps that are crushing it

14:37like yours? I would say to play long-term games with long-term people. Symmetry was launched 1 year ago but we actually started the company 2 years ago. We were really bad when we started but we never surrendered and we just kept pushing, kept improving the product, kept improving our own skills. And if you're with people that are here for the long-term, 10 plus years, it's just a matter of time that

14:58you will make it too. Well, that's great advice. Thank you Maro for coming on the channel. Love what you built. Congrats, massive success even after just a year of launching. I think people are going to love this one. So thanks for coming on. Thanks for having me, Pat. It's my pleasure to be here. All right, Gus, the new co-host of

15:12Starter Story. First of all, welcome. How was your first interview being on camera for the first time? First off, for anyone watching who's still watching this, be kind to me. You'll You won't see this in the take, but I definitely had a double take when I asked that first question. And so, for anyone watching who thinks this is easy, not easy. Pat is a pro. Yeah, what did I think of the video? It really stood out to me the whole like run experiments thing because, like I mentioned maybe in the interview if it makes it into the cut, most of my like product decisions have been like, "Oh, that sounds cool. I

15:44wish I could build that or I should just build that." With like zero data, zero information. That's kind of my first thought is like, "Oh, a lot goes into all these apps, more than just like what cool feature should I build?" Yeah, no, I mean, this is uh sometimes I think people online talk about building apps and like oh, you just prompt Claude code or whatever. How real companies actually build product is very data-based and very analytical. And I think that it's sort of like nice to know that if you want to make a change in your app, you know that if you can run a test, it doesn't work, just turn

16:16that test off. Once you have enough users, I think that's the right way to approach building anything. Yeah, I'm curious, you're really data-driven, like analytical. Whether it's with Starter Story or something else, like I think someone watching might think like how much do these really move the needle? You know, clearly he told he gave us a good example of one that like didn't matter or did matter. But like in your experience, what's that been like for

16:37you? I guess that's I'm curious. Most of the tests that you run and the things that you try don't move the needle at all. And I think just doing those and seeing that and knowing that those things don't matter is like really powerful. [music] So, that the next time you go and someone says, "Let's change the landing page or let's update the settings page or whatever." Things that don't matter, you already know, like obviously you don't want to ever make too many assumptions, but you already know like, "Hey, that's probably not going to have a huge impact. I actually know the things that are probably going

17:04to have an impact." And then you start building your sense around what to even test. So, most things don't make a difference. And I think just knowing that is good to know that, "Hey, maybe focus more on marketing than product often." But having the tools and the tool set to know how to make changes and how to track those changes I think is really powerful. All right, guys. We'll

17:24see you in the next one. Peace.