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BrainRush – Complete App Hosting & Deployment Guide

Everything discussed — from understanding how a mobile app works, to accounts, setup, building, and submitting to Google Play Store. Written for a first-time app builder with no prior publishing experience.

First — Understand How a Mobile App Works​

BrainRush is a mobile app, not a website. There is no UI to host on any server. This is the full picture of how everything connects:

Your Code (on your laptop)
        ↓
EAS Build Service (expo.dev compiles it in the cloud)
        ↓
Google Play Store (distributes it to users)
        ↓
User's Android Phone (the UI lives here — not on any server)
        ↕
Supabase (your database, auth, storage — hosted at supabase.com)

You never configure a server. You never buy a VPS. You never set up Nginx. The app UI lives on the user's phone. Supabase is already hosted for you. The only thing EAS does is compile your code into a file Android can install.

Table of Contents​

  1. Accounts You Need
  2. Set Up Your Computer
  3. Set Up Supabase
  4. Set Up Google Sign-In
  5. Set Up Anthropic API
  6. Set Up RevenueCat
  7. Set Up PostHog Analytics
  8. Configure Environment Variables
  9. Generate Your First Cards
  10. Test the App on Your Phone
  11. Push Code to Bitbucket
  12. Build the Android APK
  13. Submit to Google Play Store
  14. After Launch — What to Watch
  15. Full Infrastructure Summary
  16. Quick Reference Commands

1. Accounts You Need​

Create all of these before touching any code. Some take time to verify.

Expo — Free​

  • Go to expo.dev and sign up
  • This service builds your Android APK in the cloud
  • You do not need Android Studio or Java installed on your computer
  • No credit card needed

Supabase — Free​

  • Go to supabase.com and sign up
  • This is your entire backend — database, user authentication, and file storage
  • Free tier supports up to 50,000 monthly active users
  • No credit card needed

Google Play Console — $25 one-time fee​

  • Go to play.google.com/console and register
  • This is where your app lives so Android users can download it
  • Pay the one-time $25 developer registration fee
  • Do this first — Google takes 24 to 48 hours to verify new accounts

Anthropic — Pay as you go​

  • Go to console.anthropic.com and sign up
  • Used only by your local card generation pipeline script
  • Never runs inside the app itself
  • Add $5 credit — enough to generate over 1,000 cards
  • Generating 100 cards costs approximately Rs 10 to Rs 15

Bitbucket — Free​

  • Go to bitbucket.org and sign up
  • Free unlimited private repositories
  • Where your code is safely backed up in the cloud

RevenueCat — Free to start​

  • Go to revenuecat.com and sign up
  • Handles all subscription billing and in-app purchase complexity
  • Completely free until you reach $2,500 monthly revenue

PostHog — Free​

  • Go to posthog.com and sign up
  • Tracks how users use your app — retention, events, funnels
  • Free tier is more than enough for early growth

2. Set Up Your Computer​

Install Node.js​

  1. Go to nodejs.org
  2. Download the LTS version — the one that says Recommended for most users
  3. Install it normally like any application
  4. Verify it worked by opening your terminal and running:
node --version
# Should show something like v20.11.0

Install VS Code​

  1. Go to code.visualstudio.com and download it
  2. Install it — this is your code editor for all development

Install EAS CLI​

Open your terminal and run:

npm install --global eas-cli

# Verify it installed
eas --version

Set up the BrainRush project​

  1. Unzip the brainrush.zip file you downloaded
  2. Open VS Code
  3. File → Open Folder → select the brainrush folder
  4. Open the terminal inside VS Code (View → Terminal)
  5. Run:
npm install
# Downloads all project libraries — takes 2 to 3 minutes

3. Set Up Supabase​

Step 1 — Create your project​

  1. Log into supabase.com
  2. Click New project
  3. Fill in:
    • Name: brainrush
    • Database password: generate a strong one and save it somewhere safe
    • Region: choose the one closest to your users
      • For India choose ap-south-1 (Mumbai)
  4. Click Create new project — takes about 2 minutes to provision

Step 2 — Get your API keys​

  1. Go to Settings → API
  2. Copy these three values — you will paste them into your .env file shortly:
Key NameEnvironment VariableNotes
Project URLEXPO_PUBLIC_SUPABASE_URLSafe to include in app
anon / public keyEXPO_PUBLIC_SUPABASE_ANON_KEYSafe to include in app
service_role keySUPABASE_SERVICE_KEYSecret — pipeline only, never in app

Step 3 — Run the database schema​

  1. Go to SQL Editor → New query
  2. Open the file supabase/schema.sql from your project folder in VS Code
  3. Copy the entire contents
  4. Paste into the Supabase SQL editor
  5. Click Run
  6. You should see: Success. No rows returned.

This creates four tables:

  • cards — stores all educational cards
  • user_interactions — tracks likes, saves, skips, shares, reads
  • user_topic_weights — powers personalization
  • user_streaks — tracks daily streaks

Step 4 — Enable Row Level Security​

  1. Go to Authentication → Policies
  2. Confirm all four tables show policies listed under them
  3. If any table shows no policies, re-run the second section of schema.sql

RLS means users can only read and write their own data. Without this, any user could read every other user's data.

Step 5 — Configure Authentication​

  1. Go to Authentication → Providers
  2. Email — confirm it is toggled ON (default)
  3. Google — toggle ON (you will fill in credentials in Step 4 of this guide)
  4. Go to Authentication → URL Configuration
  5. Under Redirect URLs add both of these:
exp://localhost:8081
brainrush://
  1. Click Save

Step 6 — Create Storage bucket​

  1. Go to Storage → New bucket
  2. Name: avatars
  3. Toggle: Public
  4. Click Create bucket

This is for user profile photos — optional for MVP but good to have ready.

Supabase Free Tier — What to Know​

ResourceFree LimitReality
Database storage500 MBHolds millions of cards and interactions
Bandwidth5 GB/monthEnough for early growth
Monthly active users50,000Upgrade only when you hit this
Inactivity pauseAfter 1 week of no trafficJust click unpause in dashboard

The free tier comfortably handles your entire MVP and early user growth. Upgrade to Pro ($25/month) only when you approach 50,000 monthly active users.

4. Set Up Google Sign-In​

Google Sign-In lets users log in with one tap using their Google account. This requires both a Google Cloud project and connecting it to Supabase.

Step 1 — Create a Google Cloud project​

  1. Go to console.cloud.google.com
  2. Click Select a project → New Project
  3. Name it BrainRush
  4. Click Create

Step 2 — Configure OAuth consent screen​

  1. Go to APIs & Services → OAuth consent screen
  2. User type: External → Click Create
  3. Fill in:
    • App name: BrainRush
    • User support email: your email address
    • Developer contact email: your email address
  4. Click Save and Continue through all remaining steps
  5. No need to add scopes or test users at this stage

Step 3 — Get your SHA-1 fingerprint​

Android requires a SHA-1 fingerprint to verify your app is genuine. Run this in your project terminal:

eas login
# Enter your Expo email and password

eas credentials --platform android
# Copy the SHA1 fingerprint value shown

Step 4 — Create OAuth credentials​

  1. Go to APIs & Services → Credentials → Create Credentials → OAuth 2.0 Client ID
  2. First create the Android client:
    • Application type: Android
    • Package name: com.brainrush.app
    • SHA-1 certificate fingerprint: paste the value from Step 3
    • Click Create
  3. Then create the Web application client:
    • Application type: Web application
    • Click Create
    • Copy the Client ID and Client Secret — you need these for Supabase

Step 5 — Connect Google to Supabase​

  1. In Supabase go to Authentication → Providers → Google
  2. Toggle Enable
  3. Paste the Web Client ID and Web Client Secret from Step 4
  4. Copy the Callback URL shown — it looks like: https://xxxxxxxxxxxx.supabase.co/auth/v1/callback
  5. Go back to Google Cloud → your Web OAuth credential
  6. Under Authorised redirect URIs add the Supabase callback URL
  7. Save in both Google Cloud and Supabase

Step 6 — Add to .env file​

EXPO_PUBLIC_GOOGLE_WEB_CLIENT_ID=xxxxxxxxxxxx.apps.googleusercontent.com

5. Set Up Anthropic API​

This powers your card generation pipeline. It runs on your laptop only — it is never called from inside the app.

Steps​

  1. Go to console.anthropic.com and sign up
  2. Go to API Keys → Create Key
  3. Name it brainrush-pipeline
  4. Copy the key — it starts with sk-ant-
  5. Go to Billing → Add payment method
  6. Add $5 credit to start

Add to .env file​

ANTHROPIC_API_KEY=sk-ant-xxxxxxxxxxxxxxxx

Cost Reference​

ActionApproximate Cost
Generate 100 cardsRs 10 to Rs 15
Initial 500-card libraryUnder Rs 50
Weekly content refreshUnder Rs 20

Model used: claude-haiku-4-5-20251001 — the fastest and cheapest Claude model, perfectly suited for structured card generation at scale.

6. Set Up RevenueCat​

RevenueCat handles all the complexity of Google Play subscriptions. Without it you would need to directly implement Google Play Billing APIs — very complex. With it, the code is already written and in your project.

Step 1 — Create account and project​

  1. Go to revenuecat.com and sign up
  2. Click + New Project → name it BrainRush
  3. Add an Android app inside the project
  4. Copy the Android Public SDK Key

Step 2 — Add to .env file​

EXPO_PUBLIC_REVENUECAT_ANDROID_KEY=goog_xxxxxxxxxxxxxxxx

Step 3 — Create subscription products in Google Play​

  1. Log into play.google.com/console → your app
  2. Go to Monetize → Subscriptions → Create subscription
  3. Create two subscriptions:
Product NameProduct IDPrice
Pro Monthlycom.brainrush.pro.monthlyRs 299/month
Pro Yearlycom.brainrush.pro.yearlyRs 2,499/year

Step 4 — Connect Play Store to RevenueCat​

  1. In Google Play Console go to Setup → API access
  2. Link to a Google Cloud project
  3. Create a service account and download the JSON key file
  4. In RevenueCat → your Android app → Google Play → upload the JSON file

Step 5 — Create entitlement and offering​

  1. RevenueCat → Entitlements → + New → Name: pro
  2. RevenueCat → Offerings → + New → Name: default
  3. Attach both subscription products to the default offering
  4. Link both products to the pro entitlement

RevenueCat is completely free until you earn $2,500 per month. At that scale, their fee is a small percentage of revenue.

7. Set Up PostHog Analytics​

PostHog tells you whether users are actually coming back and using the app. Without analytics you are building blind.

Steps​

  1. Go to posthog.com and sign up
  2. Create a new project named BrainRush
  3. Go to Project Settings → Project API Key
  4. Copy the key

Add to .env file​

EXPO_PUBLIC_POSTHOG_KEY=phc_xxxxxxxxxxxxxxxx
EXPO_PUBLIC_POSTHOG_HOST=https://app.posthog.com

Events Already Tracked in BrainRush​

EventWhen It Fires
app_openedEvery cold open of the app
card_readUser spends more than 5 seconds on a card
card_likedLike button tapped
card_sharedShare button tapped
card_savedSave button tapped
topic_changedTopic chip selected
paywall_viewedPaywall screen appears
purchase_completedSubscription confirmed

The Most Important Dashboard to Set Up​

In PostHog go to Insights → Retention and configure:

  • Cohort event: app_opened
  • Retention event: app_opened

This gives you Day 1, Day 7, and Day 30 retention cohorts.

Day 7 retention above 15% — you have a real product, push on growth. Day 7 retention below 8% — fix the product before spending energy on growth.

8. Configure Environment Variables​

Create your .env file from the example:

cp .env.example .env

Open .env in VS Code and fill in every single value:

# ── Supabase ─────────────────────────────────────────────────
EXPO_PUBLIC_SUPABASE_URL=https://xxxxxxxxxxxx.supabase.co
EXPO_PUBLIC_SUPABASE_ANON_KEY=eyJhbGciOiJIUzI1NiIs...

# ── Google Sign-In ───────────────────────────────────────────
EXPO_PUBLIC_GOOGLE_WEB_CLIENT_ID=xxxxxxxxxxxx.apps.googleusercontent.com

# ── RevenueCat ───────────────────────────────────────────────
EXPO_PUBLIC_REVENUECAT_ANDROID_KEY=goog_xxxxxxxxxxxxxxxx

# ── PostHog ──────────────────────────────────────────────────
EXPO_PUBLIC_POSTHOG_KEY=phc_xxxxxxxxxxxxxxxx
EXPO_PUBLIC_POSTHOG_HOST=https://app.posthog.com

# ── Pipeline only — NEVER prefix these with EXPO_PUBLIC_ ─────
SUPABASE_SERVICE_KEY=eyJhbGciOiJIUzI1NiIs...
ANTHROPIC_API_KEY=sk-ant-xxxxxxxxxxxxxxxx

Critical Security Rule​

Keys prefixed with EXPO_PUBLIC_ are bundled into the app binary. Anyone who downloads your app can technically read these values. This is fine for the Supabase anon key, RevenueCat key, and PostHog key — they are designed to be public-facing.

SUPABASE_SERVICE_KEY and ANTHROPIC_API_KEY must never have the EXPO_PUBLIC_ prefix. These are server secrets. If exposed, someone could delete your entire database or rack up thousands of dollars in Anthropic API bills.

9. Generate Your First Cards​

You need cards in your database before the app has anything to show. Run the pipeline on your laptop:

npx tsx pipeline/generate-cards.ts

You will see output like this:

BrainRush Card Generator
Generating 100 cards...

[1/100] Your brain cannot tell the difference between a real memory...
[2/100] A day on Venus is longer than an entire year on Venus...
Rejected: Generic fact that fails quality check...
[3/100] Saving $5 a day from age 20 makes you a millionaire...

Done — 87 approved, 13 rejected.
Estimated cost: $0.18

Takes about 8 to 12 minutes for 100 cards. Cost is under Rs 15.

Verify cards were inserted​

  1. Go to Supabase → Table Editor → cards
  2. You should see rows with is_approved = true
  3. If the table is empty, check your .env has the correct SUPABASE_SERVICE_KEY

Run this regularly​

Run the pipeline every week to keep your content library fresh. Users will notice if they see the same cards again.

10. Test the App on Your Phone​

Install Expo Go on your Android phone​

  1. Open the Play Store on your Android phone
  2. Search for Expo Go and install it

Start the development server​

npm start

A QR code appears in your terminal.

Load the app​

  1. Open the Expo Go app on your phone
  2. Scan the QR code
  3. The app loads on your phone in about 10 seconds

Every time you save a file in VS Code the app refreshes automatically on your phone. This is your development loop — change code, save, see it immediately.

Test Checklist​

  • Cards load and scroll vertically
  • Topic chips at the top filter cards correctly
  • Like button works and shows active state
  • Save button works and shows active state
  • Share button opens the share sheet
  • Sign up with email creates an account
  • Confirmation email arrives in inbox
  • Sign in with email and password works
  • Google Sign-In button works
  • All four bottom tabs navigate correctly
  • Profile screen shows correct name and email
  • Sign out returns to the welcome screen

Important Note About Expo Go​

After adding Google Sign-In (a native module), Expo Go can no longer test that specific feature. Build a development APK instead:

eas build --platform android --profile development

Download and install this APK on your phone. It works exactly like Expo Go but includes all native modules. Use this for all testing going forward.

11. Push Code to Bitbucket​

Do this before building. If anything goes wrong during a build you want your code safely backed up.

Step 1 — Create a repository on Bitbucket​

  1. Log into bitbucket.org
  2. Click the + icon → Repository
  3. Repository name: brainrush
  4. Access level: Private
  5. Click Create repository

Step 2 — Push your code​

Open your terminal in the brainrush project folder and run:

git init
git add .
git commit -m "feat: initial BrainRush scaffold with auth, cards, quizzes"

# Replace with your actual Bitbucket URL shown after creating the repo
git remote add origin https://bitbucket.org/yourusername/brainrush.git
git push -u origin main

Step 3 — Verify .env is not committed​

git status

You should NOT see .env in the list. If you do see it, run this immediately:

echo ".env" >> .gitignore
git rm --cached .env
git commit -m "fix: remove .env from version control"
git push

Day-to-Day Workflow​

Every time you make changes:

git add .
git commit -m "brief description of what you changed"
git push

That is all you need as a solo builder.

12. Build the Android APK​

Step 1 — Log in to EAS​

eas login
# Enter your Expo account email and password

Step 2 — Configure the build​

eas build:configure
# Accept all prompts — this creates/updates eas.json

Step 3 — Build a preview APK for testing​

eas build --platform android --profile preview

What happens:

  • EAS uploads your code to its cloud servers
  • It compiles your React Native app into an Android APK
  • Your laptop just waits — you do not need Android Studio
  • Takes 10 to 15 minutes
  • When done you get a download link in the terminal

Download the .apk file from that link.

Step 4 — Install on your Android phone​

  1. Transfer the APK to your phone (WhatsApp to yourself, email, USB cable, Google Drive — any method works)
  2. Open the APK file on your phone
  3. Android will ask: Allow installs from this source → tap Allow
  4. Install it
  5. Open BrainRush and test thoroughly as a real user would

This preview build is the closest experience to what users will actually download. Test everything again — auth, cards, quizzes, subscriptions in sandbox mode.

Step 5 — Build the production AAB for Play Store​

Once you are happy with testing:

eas build --platform android --profile production

This creates an .aab (Android App Bundle) file — the format Google Play requires. The AAB is smaller and more optimised than an APK. Download it when the build completes.

13. Submit to Google Play Store​

Step 1 — Create your app in Play Console​

  1. Log into play.google.com/console
  2. Click Create app
  3. Fill in:
    • App name: BrainRush
    • Default language: English (United States)
    • App or game: App
    • Free or paid: Free
  4. Accept the developer program policies
  5. Click Create app

Step 2 — Complete the store listing​

Go to Store presence → Main store listing and fill in:

Short description (80 characters max):

Learn something surprising every day. Cards, quizzes, streaks.

Full description (4,000 characters max): Write 3 to 4 paragraphs covering:

  • What BrainRush does
  • Who it is for (ages 13 to 22)
  • What topics it covers
  • How the quiz and streak system works
  • Why it is different from other learning apps

Step 3 — Upload graphics​

You need all of these before you can submit:

AssetRequired SizeHow to Make It
App icon512 x 512 PNGCanva.com — free
Feature graphic1024 x 500 PNGCanva.com — free
Phone screenshotsMinimum 2, maximum 8Screenshot from your phone

For screenshots: scroll through the app on your phone and take screenshots of the home feed, a quiz, the streaks screen, and the profile screen.

Step 4 — Create a privacy policy​

Google Play requires a privacy policy for all apps. Create one free:

  1. Go to app-privacy-policy-generator.firebaseapp.com
  2. Fill in your app name and your email
  3. Toggle on: collects email addresses, uses analytics, uses third-party SDKs
  4. Click Generate
  5. Copy the generated policy text
  6. Go to sites.google.com → create a free site → create a page → paste the policy
  7. Publish the site and copy the URL
  8. In Play Console go to App content → Privacy policy → paste the URL

Step 5 — Complete content rating​

  1. Play Console → Policy → App content → Content rating
  2. Click Start questionnaire
  3. Select category: Education
  4. Answer all questions honestly
    • BrainRush has no violence, sexual content, or user-generated content
  5. Submit — you receive a rating immediately

Step 6 — Submit the build​

Option A — Using EAS (recommended):

eas submit --platform android

Option B — Manual upload:

  1. Play Console → Production → Releases → Create new release
  2. Click Upload and select your .aab file
  3. Add release notes: Initial launch of BrainRush — learn something new every day
  4. Click Save → Review release → Start rollout to Production

Step 7 — Wait for Google's review​

  • First submission takes 1 to 7 days for review
  • You will receive an email when approved
  • You will receive an email if they require changes
  • If rejected, fix what they ask and resubmit — this is completely normal

14. After Launch — What to Watch​

Share it everywhere on day one​

  • Share the Play Store link in WhatsApp groups and family chats
  • Post in Reddit communities: r/india, r/learnprogramming, r/teenagers, r/education
  • Post on LinkedIn using the 3 to 4 line posts you prepared
  • Share in relevant Discord servers and Telegram student groups
  • Ask every early user to leave an honest review on the Play Store

Ask the right questions from early users​

Do not ask "do you like it?" — people will say yes to be polite.

Ask these specific questions instead:

  • What confused you in the first 30 seconds?
  • Did you feel like opening it again after you closed it?
  • What would make you open this every single day?
  • What felt unnecessary or annoying?

The answers to these four questions will tell you exactly what to fix.

Metrics to track in PostHog​

MetricWhat it tells youTarget
D1 retention% who open app next dayAbove 30%
D7 retention% still using after 1 weekAbove 15%
D30 retention% still using after 1 monthAbove 8%
Cards per sessionHow many cards read per visitAbove 5
Quiz completionDo users finish quizzesAbove 60%

D7 retention above 15% — the core loop works, focus on growth. D7 retention below 8% — fix the product before growing.

Update the app every 2 weeks​

# Generate fresh cards
npx tsx pipeline/generate-cards.ts

# Build new version
eas build --platform android --profile production

# Submit update
eas submit --platform android

Increment the version number in app.json before each update:

"version": "1.0.1"

15. Full Infrastructure Summary​

Every service that runs BrainRush and what it costs:

ServiceWhat it doesMonthly Cost
SupabaseDatabase, auth, storageFree
Expo EASBuilds APK and AAB in cloudFree
Google Play ConsoleDistributes app to Android usersRs 2,000 one-time only
Anthropic APIGenerates educational cards~Rs 50
RevenueCatHandles subscription billingFree
PostHogUser analytics and retentionFree
BitbucketStores your codeFree
Total monthly~Rs 50 per month

You can run BrainRush for under Rs 50 a month until you have thousands of paying users. That is the extraordinary advantage of this tech stack. Five years ago you would have needed a team and thousands of dollars a month to run infrastructure for an app like this.

16. Quick Reference Commands​

These are the commands you will type most often:

# ── Development ───────────────────────────────────────────────
npm start                                    # start dev server, scan QR with Expo Go

# ── Content ───────────────────────────────────────────────────
npx tsx pipeline/generate-cards.ts           # generate 100 new cards (~Rs 15)

# ── Credentials ───────────────────────────────────────────────
eas login                                    # log in to Expo account
eas credentials --platform android           # get SHA-1 for Google OAuth setup

# ── Building ──────────────────────────────────────────────────
eas build:configure                          # first-time setup only
eas build --platform android --profile development   # dev build with native modules
eas build --platform android --profile preview       # test APK for your phone
eas build --platform android --profile production    # AAB for Play Store

# ── Submitting ────────────────────────────────────────────────
eas submit --platform android                # submit to Google Play Store

# ── Code backup ───────────────────────────────────────────────
git add .                                    # stage all changes
git commit -m "describe what changed"        # save a snapshot
git push                                     # upload to Bitbucket

Timeline Summary​

DaysWhat you are doing
Day 1Create all accounts, set up computer, run npm install
Day 2Set up Supabase, run schema, get API keys
Day 3Set up Google Sign-In, Anthropic, RevenueCat, PostHog
Day 4Fill in .env, generate first 100 cards, test locally
Day 5 to 14Build features, test on phone daily, fix bugs
Day 14Push to Bitbucket, build preview APK, test thoroughly
Day 15Build production AAB, create Play Store listing
Day 16Submit to Play Store
Day 17 to 23Wait for Google review (1 to 7 days)
Day 24+App is live — share, collect feedback, iterate

Two weeks of focused 2-hour daily sessions gets you to a live app on the Play Store.

BrainRush — Built with Expo, React Native, TypeScript, NativeWind, Supabase, Claude Haiku, RevenueCat, and PostHog.