HotDrop

Local two-way file transfer between macOS and Android over Wi-Fi or Personal Hotspot — no internet, no cloud, no cables.

---

What it does

Direction	How
Mac → Android	Drag a file onto HotDrop on Mac, scan the QR code on Android, tap Download
Android → Mac	Pick a file on Android, tap Upload — it lands in ~/Movies/HotDrop

Transfers are resumable: if the connection drops mid-way, reconnect and tap Resume — it picks up from the last saved byte.

---

Requirements

• macOS 12 Monterey or later
• Node.js 18 or later (download)
• Android device (any modern browser — Chrome recommended) on the same network

---

Installation

git clone https://github.com/vismaytiwari/hotdrop.git
cd hotdrop
npm install

---

Running

npm start

This builds the TypeScript source and launches the Electron app.

---

Step-by-step usage

1 · Get both devices on the same network

Option A — Mac Personal Hotspot

1. Open System Settings → General → Sharing
2. Enable Internet Sharing (share from Wi-Fi/Ethernet → to Wi-Fi)
3. Connect your Android phone to that hotspot

Option B — Shared Wi-Fi router Just connect both Mac and Android to the same Wi-Fi network.

---

2 · Start a session on Mac

1. Launch HotDrop (npm start)
2. Set a Password in the left sidebar (default: hotdrop)
3. Optionally adjust Max receive (maximum file size Android can upload)
4. Click Start session
5. A QR code and URL appear — the app is now listening

---

3 · Connect from Android

1. Open your Android camera app and scan the QR code
   (or manually type the URL shown in the app into Chrome)
2. Android will show a security warning about the certificate — this is expected.
   Tap Advanced → Proceed to [IP address] to trust the local self-signed certificate.
   You only need to do this once per session.
3. Enter the password and tap Connect

---

4 · Send a file Mac → Android

1. On Mac, drag a file onto the Mac → Android drop zone, or click Select file
2. On Android, the file appears in the Download From Mac section
3. Tap Download — the browser saves it to your Downloads folder

---

5 · Send a file Android → Mac

1. On Android, scroll to the Send to Mac section
2. Tap Choose file and select a file from your phone
3. Tap Upload
4. The file is saved to ~/Movies/HotDrop/ on your Mac

Pause and Resume

• Tap Pause at any time during an upload
• Tap Resume to continue — progress is never lost
• If the connection drops, reconnect from step 3 and tap Resume

---

6 · Stop the session

Click Apply & restart in the Mac sidebar to change settings, or close the app.

---

Keyboard shortcut

Press ⌘ Shift M to toggle the app between full window and a compact mini-player that shows live transfer progress.

---

Receive folder

Uploaded files from Android land in ~/Movies/HotDrop by default. The folder is created automatically.

---

Security notes

• All traffic uses self-signed TLS (HTTPS on the local network) — this is why Android shows a certificate warning
• Each session generates a fresh 256-bit random token — the QR code URL contains it
• Login is rate-limited: 5 failed attempts trigger a 30-second lockout
• Only one Android client can be connected per session
• Auth cookies are HttpOnly, Secure, SameSite=Strict
• The app only listens on your local network interface — it is not reachable from the internet

---

Build for distribution

npm run dist:mac

Produces a signed .dmg and .zip in the release/ folder.

---

Running tests

npm test

---

Tech stack

Layer	Technology
Desktop shell	Electron
Language	TypeScript
Local server	Express 5 + Node https
TLS	selfsigned (self-signed cert generated at start)
QR codes	qrcode
Tests	Vitest

---

License

MIT