How We Built It: $30K/month Mobile App

Eyal And Yali

• Built Prop GPT, a mobile app that grew to $30,000 per month.
• Launched the app about a year before the interview.
• Got stuck around $1,000 to $2,000 MRR with the first version.
• Spent 4 months rebuilding the product from scratch.
• Relaunched and grew quickly after improving the product.
• Showed that distribution alone did not matter when the product experience was weak.

Prop GPT

• Provides sports betting analytics through a machine learning algorithm.
• Gives users access to models for analyzing their own picks.
• Scans bets every day and shows pre-analyzed betting opportunities.
• Rebuilt the product after realizing users wanted the app to give them the right answers instead of making them input bets manually.

Metrics And Financials

• Makes about $30,000 per month.
• Has more than 40,000 downloads.
• Has more than 3,000 paying customers.
• Converts 48% of downloads into trials.
• Earns around $3.30 for every user who downloads the app.
• Hit a peak of $40,000 MRR about 2 and a half months after relaunching.
• Reached 2,000 downloads in a single day.
• Raised ARR from about $8,000 to $38,000 in about 3 days after one influencer video reached 600,000 views.
• Runs at roughly 50% margins.

Original Build And Problem

• Spent about 5 months building the first version of Prop GPT.
• Launched in the middle of the NFL season.
• Averaged about 20 downloads per day early on.
• Converted about 5 to 10 users per day from downloads to free trials.
• Could not push beyond $1,000 to $2,000 MRR despite having strong influencer-driven distribution.
• Saw that many people started trials but almost nobody stayed after the trial ended.
• Realized the app’s conversion problem meant users liked the idea but did not get the experience they expected.

Rebuild And Relaunch

• Shut down all marketing for 4 months.
• Focused only on engineering and design work during the rebuild.
• Relaunched the new version on April 15 at about $1,700 MRR and around $15 per day.
• Went all in on marketing again during the NBA playoffs the next month.
• Saw paid conversion rise above 50% after the rebuild.

Product Playbook

• Stay extremely humble about the product.
• Talk to users and use analytics platforms like PostHog to identify patterns that do not match the app design.
• Understand exactly who the app is for and what their pain points are.
• Listen to the data instead of assuming the product works.
• Watch key conversion points, such as trial conversion and trial-to-paid conversion.
• Obsess over analytics to see where users fall off during onboarding.
• Track feature clicks to identify the app’s strongest value proposition.
• Use what customers actually do inside the app to improve product and marketing.

Growth Strategy

• Started with influencer marketing because Eyal had worked with successful app founders before.
• Spent a few thousand dollars on influencer marketing to test how many downloads the app could get.
• Uses influencer marketing as a scaling channel once the product works.
• Values creators because their followers engage deeply and convert faster when they see someone they admire using the product.
• Sees organic social as powerful because one viral video can change the business.

Tech Stack And Costs

• Built the app in a React Native repo.
• Uses TypeScript and Python for machine learning algorithms.
• Uses automated fetching for sports data.
• Stores a large database on Neon.
• Uses RevenueCat for revenue dashboards.
• Uses Superwall for paywalls.
• Pays about $0.20 per conversion to Superwall.
• Pays about 1% to RevenueCat.
• Pays about $100 per month for data APIs with real-time sports data.
• Pays about $10 per month for Neon database bandwidth.
• Pays about $20 per month for LLM costs.
• Spends about $10,000 per month on marketing.

Lessons And Advice

• Recommends having a co-founder who can provide support when things get hard.
• Advises entrepreneurs to be honest and scientific about whether their product has enough demand.
• Says proving the opportunity to yourself makes it much easier to prove it to investors and future team members.