Second Earth · AI Product Studio · Seoul, Korea

Second Earth.
Global impact.

Second Earth is a Seoul-based AI product studio founded by Sunwoo Kim. 13 apps shipped. 60+ countries. Growing fast.

The brand is also written as "secondearth", "second earth", and "세컨드어스".

13Apps Shipped
60+Countries
200K+Downloads
4.9★Rating
Flagship Product · iOS & Android

AIBookCraft

AI Storybook Creator for Children

Parents and educators use AIBookCraft to create personalized children's storybooks in minutes. AI generates the plot, dialogue, and full-page illustrations — tailored to each child's name, age, and imagination. Export as a print-quality PDF. A story that truly belongs to them.

564
Active Subscribers
4.9
App Store Rating
100K+
Total Downloads
Growing
Revenue Trend
Used in 60+ countries by parents worldwide
Rated #2 for 'ai book writer' on App Store
1% free-to-paid conversion rate (strong PMF)
📚
AIBookCraft
AI Generating...
Generating your story100%

"The Dragon Who
Lost His Fire"

A story for Emma, age 7

🐉
AI Illustrated
Page 1 of 12

12 pages · AI text + artPDF Ready
✓
Story Complete!
12 pages · Illustrated · Ready to export
🎯Trigger
🤖AI Script
🎨Image Gen
🎬Video Gen
📱Auto Post
Execution #1,247Morning Routine ASMR
Running
4 of 5 nodes complete~8s remaining
Script ✓Image ✓Video ✓Posting…
LLM
Gemini Flash
Image
FLUX 2 Flex
Video
Kling v3 Pro
Auto-posts to:📸 Instagram🎵 TikTok▶️ YouTube𝕏 X💼 LinkedIn
Flagship B2B Platform · Web

Moltor

AI Content Workflow Automation

Moltor is a visual AI workflow builder that turns your content strategy into a fully automated pipeline. Connect AI models, generate videos, and publish to every platform — automatically. Content at scale, without the scale of a team.

  • 17 node types: AI, Image, Video, Audio, Control Flow
  • 50+ models: fal.ai, ElevenLabs, KIE, Creatomate
  • Visual drag-and-drop workflow builder
  • AI chat: describe a workflow, get it built instantly
  • Auto-schedule and post to 5 social platforms
  • Real-time execution monitoring and error handling
Next.js 16ConvexReact FlowTypeScriptAI SDK

The Story

Solo.

But not small.

Second Earth is one person, one mission, one laptop. No VC funding. No co-founder. Just relentless shipping and a global audience that keeps growing.

13 apps.

All shipped.

AIBookCraft
✅
TripPack AI
Freelytic
🎮
PupFi
NoteCube
Random Challenge
🧠
🎭
EveryTracker
🌍
⚡

60+ countries.

Organically.

ASO, paid ads, word-of-mouth — every growth channel dialed in. A product people genuinely love to share.

⭐⭐⭐⭐⭐

4.9 stars.

Earned.

Not bought, not gamed. Earned from parents who watch their child's eyes light up when they see their very own personalized storybook.

What's next?

Everything.

🚀
Moltor Launch
B2B SaaS for AI content automation
📈
Scale Globally
More countries, more impact
🌍
Full-Time
Quit job. Build full-time.

By the Numbers

Real numbers.
Real impact.

0+

Countries

0K+

Downloads

0.0

App Store Rating

0

Apps Shipped

0

Paid Subscribers

The Portfolio

13 apps. All live.

Every app ships with full analytics, global localization, and subscription monetization.

AIBookCraft
AIBookCraftFlagship
AI Storybook Creator
iOS & Android
4.9
⚡
MoltorFlagship
AI Workflow Automation
Web
✅
HabitStamp
Habit Tracker
iOS & Android
4.7
TripPack AI
TripPack AI
AI Packing List
iOS
4.6
Freelytic
Freelytic
Freelancer Analytics
iOS
4.5
PupFi
PupFi
Pet Life Manager
iOS
4.4
EveryTracker
EveryTracker
Universal Tracker
iOS
4.3
NoteCube
NoteCube
Mandala Art & Notes
iOS
4.3
🎮
APT Game
Party Games
iOS
4.4
🧠
MindBot
AI Mental Health
iOS
4.2
🎭
Soul
Celebrity Life Sim
iOS
4.1
🌍
TripDNA
Friend Memory App
iOS
4.2
Random Challenge
Random Challenge
Daily Challenge App
iOS
4.0

All apps built on the same battle-tested stack

React NativeExpo SDK 54TypeScriptAWS AmplifyRevenueCatMixpanelOneSignalSentry

What Makes This Unique

Built differently.

One engineer. The full stack. Mobile to AI backend to web platform.

AI-First From Day One

Every product is built around AI — not bolted on. Gemini, GPT, Bedrock, and specialized models all in the toolkit.

Rapid Execution

Idea to live App Store product in weeks. Pretotyping before building. Ship, measure, iterate. No overthinking.

Global From Day One

Every app ships with full i18n, multi-currency, and 60+ country coverage from the very first release.

Cross-Platform Native Quality

React Native + Expo gives native performance on iOS and Android from a single codebase. Zero compromise.

Data-Driven Everything

Mixpanel funnels, RevenueCat metrics, Statsig A/B tests. Every decision backed by data, never gut feeling.

Privacy-Respecting

Minimal data collection by design. Transparent policies. Users trust the product — it shows in the reviews.

The full tech stack

Battle-tested. Production-grade. Running at global scale.

Mobile

React NativeExpo SDK 54TypeScriptNativeWind

Backend

AWS Amplify Gen2Amazon BedrockAWS LambdaConvex

AI / ML

Gemini FlashGPT-4oFLUX 2Kling v3 ProElevenLabs

Analytics

MixpanelFirebase AnalyticsSentryStatsig

Revenue

RevenueCatSuperwallApp StoreGoogle Play

Growth

AppTweak ASOOneSignalFirebase Remote Config

The Builder

Hi, I'm Sunwoo Kim

I'm a mobile engineer from Seoul, South Korea, building Second Earth as a solo founder — on evenings and weekends — while working full-time at a tech company. My mission: go full-time to accelerate humanity's productivity through AI-powered tools. Building in public, one app at a time.

Second Earth Inc. — 1-person company
Seoul, South Korea · SparkPlus Jamsil
sunwoo@secondearth.io

The goal: Build in public, prove the model, then quit my 9-to-5 to run Second Earth full-time. The clock is ticking. The apps keep shipping.

Mission

Accelerating the future through productivity. Build simple, powerful AI tools that help people reclaim their most valuable resource: time.

Philosophy

Data first, always. Ship fast, measure everything, iterate ruthlessly. Execution beats perfection. A shipped product beats a perfect idea.

Stack

React NativeTypeScriptExpo SDK 54AWS AmplifyAmazon BedrockNext.js 16ConvexAI SDK