I Built DocuMind Mobile in One Day, Not Months — Thanks to Replit Agent

Product Manthan — Sun, 03 May 2026 08:38:30 +0000

A mobile-first AI document vault that remembers everything for you, built end-to-end with Replit Agent.

The Problem That Wouldn't Go Away

Every adult I know has the same drawer — physical or digital — full of documents they "might need someday." Passport renewal date? Buried in a PDF. Insurance policy expiry? Somewhere in your email. The visa paperwork you submitted last time? Good luck.

I wanted a mobile app that didn't just store documents — it had to understand them. Tell me when things expire. Let me ask "what did I submit for my last visa renewal?" in plain English. Share a folder of tax docs with my accountant the way I'd share a Google Drive link.

That app didn't exist. So I built it. With one teammate: Replit Agent.

Meet DocuMind Mobile

📱 Try it on your phone: https://agent-forge-productmanthana.replit.app/mobile/
(Scan the QR with Expo Go on iOS or Android)

DocuMind is a mobile-first AI document vault. The headline features:

📄 Upload anything — PDFs, Word docs, scanned images (HEIC, JPG, PNG). All OCR'd and indexed.
💬 Chat with your documents — "When does my passport expire?" or "Summarize my last three tax returns." Streaming answers, with citations.
🔔 AI-suggested reminders — Snap a photo of a document, the app reads it, finds future dates (expiry, renewal, appointments), and offers to set reminders. One tap.
📁 Drive-style sharing — Share folders or individual docs with read-only or read-write permissions. Live updates — add a doc, recipients see it instantly on their phone.
💭 Group discussions — 1-on-1 chats and group conversations with native push notifications. Drop a folder right into chat.
🔐 Phone + PIN auth — No passwords. Reset via security question. Built for real humans.
🌓 iOS Liquid Glass + Android Material — native tab bars, native feel on every device.

The Mobile Stack (Built Entirely on Replit)

Layer	Tech
Framework	Expo SDK 54 + React Native
Navigation	expo-router (file-based, NativeTabs)
API	Express 5 + TypeScript
Database	PostgreSQL + Drizzle ORM
Vector search	Weaviate (semantic doc search)
AI	Gemini 3 Flash + GPT-4o (fallback)
Vision/OCR	Gemini vision + GPT-4o-mini fallback
Auth	Phone + PIN, custom JWT
Push	Expo Notifications
Hosting	Replit Deployments

It's a pnpm monorepo with the mobile app, an Express API, and shared TypeScript libs all running side-by-side. All wired up by Replit's path-based proxy — zero infra config from me.

The Real Story: What Replit Agent Actually Did

This is the part I want fellow builders to hear. I didn't just "use AI to autocomplete code." Replit Agent worked as a full-stack mobile engineer pair.

It scaffolded the monorepo from scratch. I described what I wanted; the agent set up Expo, the API server, TypeScript project references, and shared lib packages.

It built features end-to-end. I'd say "add 1-on-1 and group messaging with push notifications." The agent designed the database schema, wrote the migration, built the Express routes with Zod validation, generated typed React Query hooks from an OpenAPI spec, built the React Native screens, wired up Expo push tokens, and shipped it. I reviewed and tested on my phone.

It debugged production issues with me. When users reported "Profile and Admin buttons don't work in the More tab on TestFlight," the agent traced it through expo-router's NativeTabs behavior (turns out router.push() doesn't navigate to hidden native tab triggers), restructured the routes, updated every caller across the codebase, and added back buttons — all while I was answering Slack messages.

It handled the gnarly mobile stuff. Image OCR with HEIC support, push token registration, deep links from email invites, iOS Liquid Glass tab badges that also work on the classic Android tab bar — the agent handled all of it without me touching the native code.

It refused shortcuts I would've taken. When I asked for "fake it for now" mocked data on the AI suggestions feature, the agent pushed back: "let's wire it to real Gemini vision — it's two more functions." It was right.

The Numbers

~40 mobile screens in Expo SDK 54
~120 API routes (all Zod-validated)
2 LLM providers with automatic fallback
2 vision models for OCR with HEIC support
0 lines of glue code I wrote myself for the proxy, deployments, or env management — Replit handled it

What I Learned

The thing nobody tells you about building with an AI agent: your job changes from typing code to making good decisions fast. I spent my time on product calls — "should sharing default to read-only?" "should push notifications fire for the sender too?" — instead of fighting Expo build configs or webpack.

The agent did 90% of the keystrokes. I did 100% of the direction. That's the right split.

Try It on Your Phone

📱 Scan the QR: https://agent-forge-productmanthana.replit.app/mobile/
(Install Expo Go from the App Store / Play Store first, then scan)

💬 Built for: anyone who's ever lost an important document or forgotten an expiry date.

If you're sitting on a mobile app idea, stop waiting. Open Replit, describe what you want, and let the agent start building. You'll be surprised how far you get in an evening.

Built with ❤️ using Replit Agent for the Replit 10 Year Buildathon.

ReplitAgent #BuildInPublic #Expo #ReactNative #MobileApp

DEV Community: Product Manthan