Cookie Manager

A Chrome/Arc extension for exporting, importing, and syncing cookies across browsers on the same LAN.

Features

• Export — save current site cookies to a JSON file
• Import — load cookies from a JSON file into the current browser
• Clear — remove all cookies for the current site
• Peer sync — push cookies directly to another browser on the same network (no cloud, no file)

Browser support

Chrome and Arc (any Chromium-based browser that supports Manifest V3 extensions and Native Messaging).

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Installation

Extension

1. Clone or download this repository
2. Open chrome://extensions (or arc://extensions)
3. Enable Developer mode
4. Click Load unpacked and select this directory
5. Note the extension ID shown on the card

Sync daemon (optional — required for peer sync)

The peer sync feature requires a small native binary that handles mDNS discovery and LAN HTTP communication.

Download the binary

Grab the latest sqrd-cookie-sync-nmhost-darwin-<arch> from GitHub Releases and place it at:

~/Library/Application Support/sqrd-cookie-sync/sqrd-cookie-sync-nmhost

Then make it executable:

chmod +x ~/Library/Application\ Support/sqrd-cookie-sync/sqrd-cookie-sync-nmhost

Register the Native Messaging manifest

cd daemon
./install.sh <your-extension-id>

This writes the NM manifest for both Chrome and Arc. No elevated privileges required.

Finding your extension ID: Go to chrome://extensions (or arc://extensions), enable Developer mode, and look for the 32-character ID under the extension name (e.g. abcdefghijklmnopqrstuvwxyzabcdef).

Note: Chrome assigns a different ID each time you load an unpacked extension on a new machine. If you need a stable ID across machines, add a "key" field to manifest.json — see the Chrome docs on stable extension IDs.

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How peer sync works

1. Open the extension popup — Chrome spawns the sync daemon automatically
2. The daemon advertises itself on the LAN via mDNS (_cookiesync._tcp) and starts a local HTTP server on a random port
3. Other open popups on the same network appear in the Nearby Peers list
4. Click → next to a peer to push the current site's cookies to their browser
5. The receiving popup silently imports the cookies within ~2 seconds
6. When the popup closes, the daemon exits — no persistent background process

Previously seen peers are saved locally and shown immediately on next open (greyed out if currently unreachable).

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Cookie file format

{
  "exportedAt": "2025-01-01T00:00:00.000Z",
  "cookies": [
    {
      "name": "session",
      "value": "abc123",
      "domain": "example.com",
      "path": "/",
      "secure": true,
      "httpOnly": true,
      "expirationDate": 1893456000
    }
  ]
}

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Building the daemon from source

Requires Go 1.22+.

cd daemon
go mod tidy
go build -o sqrd-cookie-sync-nmhost ./cmd/nmhost

Cross-compile for macOS:

GOOS=darwin GOARCH=arm64 CGO_ENABLED=0 go build -o sqrd-cookie-sync-nmhost-darwin-arm64 ./cmd/nmhost
GOOS=darwin GOARCH=amd64 CGO_ENABLED=0 go build -o sqrd-cookie-sync-nmhost-darwin-amd64 ./cmd/nmhost

CI builds both architectures automatically on v* tags via GitHub Actions.

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Project structure

cookie-manager/
├── manifest.json                 # MV3 extension manifest
├── popup.html                    # Extension popup UI
├── popup.js                      # Export / import / clear / peer sync logic
└── daemon/
    ├── cmd/nmhost/main.go        # Entry point — wires all components
    ├── id.go                     # Stable UUID identity
    ├── queue.go                  # In-memory incoming cookie queue
    ├── peers.go                  # Peer persistence (peers.json)
    ├── server.go                 # LAN HTTP server (POST /sync, GET /ping)
    ├── native.go                 # Native Messaging stdio protocol
    ├── mdns.go                   # mDNS advertise + discover (zeroconf)
    ├── install.sh                # Writes NM manifest for Chrome and Arc
    └── go.mod

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Runtime paths (macOS)

Item	Path
Binary	~/Library/Application Support/sqrd-cookie-sync/sqrd-cookie-sync-nmhost
Peer identity	~/Library/Application Support/sqrd-cookie-sync/id
Known peers	~/Library/Application Support/sqrd-cookie-sync/peers.json
Chrome NM manifest	~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.thundersquared.cookiesync.json
Arc NM manifest	~/Library/Application Support/Arc/NativeMessagingHosts/com.thundersquared.cookiesync.json

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Privacy

All communication is local-network only. No data leaves your LAN. The LAN HTTP endpoint is open (no authentication) — the trust boundary is your local network.