StableSyncQuiz

Real-time quiz progress backup for Coursera—resume instantly across any device.

Score: 7.7/10GermanyMedium BuildReady to Spawn
Brand Colors

The Opportunity

Problem

Coursera's mobile app crashes during quizzes, preventing students from studying effectively on the go.

Solution

StableSyncQuiz runs as a lightweight browser extension and companion PWA that captures quiz state in real-time from Coursera web, backing it up to the cloud. If the app crashes on mobile, switch to PWA and resume exactly where you left off. Ideal for commuters switching between phone, tablet, and laptop.

Target Audience

Busy students enrolled in online courses on platforms like Coursera who depend on mobile apps for studying during commutes or short breaks.

Differentiator

Live state capture from Coursera web/app via extension + AI-predicted crash recovery.

Brand Voice

friendly

Features

Browser Extension

must-have25h

Chrome ext to capture quiz state live.

PWA Resume

must-have20h

Companion app to load and continue quizzes.

Cloud Backup

must-have18h

Secure real-time sync of quiz state.

Multi-Device Resume

must-have15h

Seamless handover between devices.

Crash Alerts

must-have12h

Notify on potential crash risks.

Session History

must-have14h

Log all sessions for review.

Quick Export

nice-to-have6h

One-click state export.

Custom Timers

nice-to-have7h

Add study timers to sessions.

Collaborative Resume

nice-to-have10h

Share session with study partner.

Integration with Calendar

future12h

Schedule quiz sessions.

Total Build Time: 139 hours

Database Schema

users

ColumnTypeNullable
iduuidNo
emailtextNo
extension_idtextYes
created_attimestampNo

sessions

ColumnTypeNullable
iduuidNo
user_iduuidNo
coursera_urltextNo
started_attimestampNo

Relationships:

  • user_id -> users.id

states

ColumnTypeNullable
iduuidNo
session_iduuidNo
quiz_statejsonbNo
timestamptimestampNo

Relationships:

  • session_id -> sessions.id

devices

ColumnTypeNullable
iduuidNo
user_iduuidNo
device_tokentextNo

Relationships:

  • user_id -> users.id

API Endpoints

POST
/api/sessions

Start new session backup

🔒 Auth Required
POST
/api/states/:sessionId

Update state

🔒 Auth Required
GET
/api/sessions/:id/resume

Get latest state

🔒 Auth Required
GET
/api/sessions

List sessions

🔒 Auth Required
POST
/api/extension/register

Register extension

🔒 Auth Required

Tech Stack

Frontend
Next.js 14 + Tailwind + Shadcn/ui + Chrome Extension API
Backend
Supabase Edge Functions
Database
Supabase Postgres
Auth
Supabase Auth
Payments
Stripe
Hosting
Vercel
Additional Tools
Pusher (realtime)Chrome Webstore

Build Timeline

Week 1: Auth and ext scaffold

45h
  • User auth
  • Extension MVP

Week 2: State capture

40h
  • Live backup logic
  • DB schema

Week 3: PWA resume

40h
  • Companion PWA
  • Resume flow

Week 4: Realtime sync

35h
  • Pusher integration
  • Alerts

Week 5: Polish

30h
  • Payments
  • Nice features

Week 6: Publish and test

25h
  • Ext to store
  • Full deploy

Week 7: Bug fixes

20h
  • Cross-browser test
Total Timeline: 7 weeks • 235 hours

Pricing Tiers

Free

$0/mo

No multi-device

  • 3 active sessions
  • Basic backup

Pro

$25/mo
  • Unlimited sessions
  • Multi-device
  • Alerts

Unlimited

$75/mo
  • All Pro
  • Team sharing
  • API access

Revenue Projections

MonthUsersConversionMRRARR
Month 1801.5%$30$360
Month 66003.5%$630$7,560

Unit Economics

$18
CAC
$220
LTV
7%
Churn
86%
Margin
LTV:CAC Ratio: 12.2xExcellent!

Landing Page Copy

Resume Coursera Quizzes After Any Crash

Extension + PWA auto-backups your progress—switch devices, never restart.

Feature Highlights

Live state capture
Instant resume
Cross-device sync
Crash notifications
Session logs

Social Proof (Placeholders)

"'Rescued my half-done quiz!' - Jordan, Engineering student"
"'Perfect for train commutes.' - Sam"

First Three Customers

Target Coursera crash Twitter complaints with DM offers for free Pro; run giveaway in r/coursera for extension installs; interview 5 users for feedback post-signup.

Launch Channels

Product Huntr/courseraChrome Web StoreTwitter edtechHacker News

SEO Keywords

coursera quiz progress syncresume coursera quiz after crashcoursera multi device quizzescoursera backup extensionfix coursera app freeze

Competitive Analysis

Evernote Web Clipper

evernote.com
Free + $14/mo
Strength

Page clipping

Weakness

No dynamic state or quiz resume

Our Advantage

Real-time quiz-specific backup

Notion

notion.so
Free + $10/mo
Strength

Note sync

Weakness

Manual, no live capture

Our Advantage

Automated for quizzes

🏰 Moat Strategy

Extension install lock-in + proprietary state serialization.

⏰ Why Now?

Remote learning peak, browser extensions gaining traction for productivity.

Risks & Mitigation

technicalmedium severity

Extension review delays

Mitigation

Prepare for multiple stores

legallow severity

Browser policy changes

Mitigation

PWA fallback

Validation Roadmap

pre-build5 days

Extension prototype demo to 20 users

Success: 15 positive feedbacks

Pivot Options

  • General tab saver
  • Study session recorder
  • Coursera note clipper

Quick Stats

Build Time
235h
Target MRR (6 mo)
$800
Market Size
$4000.0M
Features
10
Database Tables
4
API Endpoints
5