Web Server Guide

This guide explains how to use CrossInk’s built-in web server for file transfer, device settings, Wi-Fi/OPDS management, and SD-card font management.

Overview

The web server is available while the device is in File Transfer or Calibre Wireless mode. It can:

  • Upload, download, rename, move, and delete files on the SD card
  • Create folders
  • Edit many device settings from a browser
  • Manage saved Wi-Fi networks and OPDS servers
  • Upload and delete .cpfont SD-card font families
  • Accept WebDAV clients and Calibre wireless uploads

The server does not require authentication. Use it only on trusted private networks or in hotspot mode when you control who is connected.

Starting File Transfer

  1. From the Home screen, select File Transfer.
  2. Choose one of the available modes:
Mode Use when
Join Network You want the reader to join an existing Wi-Fi network.
Calibre Wireless You want to receive books from the CrossPoint Calibre plugin workflow.
Create Hotspot You want the reader to create its own open Wi-Fi network.

Join Network Mode

  1. Select Join Network.
  2. Pick a 2.4 GHz Wi-Fi network from the scan results.
  3. Enter the password if prompted.
  4. Save credentials if you want the reader to reconnect automatically next time.

After connection, the reader shows:

  • The connected SSID
  • A QR code for the web URL
  • The direct IP URL, for example http://192.168.1.102/
  • The mDNS fallback URL, usually http://crosspoint.local/

Use either URL from a phone, tablet, or computer on the same network.

Create Hotspot Mode

  1. Select Create Hotspot.
  2. Connect your phone or computer to the open Wi-Fi network:
CrossPoint-Reader
  1. Open the URL shown on the reader. http://crosspoint.local/ is preferred when supported; the fallback IP is typically http://192.168.4.1/.

The reader displays one QR code for joining the hotspot and another QR code for opening the web interface.

Calibre Wireless Mode

Calibre Wireless starts the same web server in station mode, then displays setup instructions and upload progress on the reader. Use this mode with the CrossPoint Calibre plugin or other clients that speak the documented WebSocket upload protocol.

For Calibre OPDS browsing, add /opds to the catalog URL when configuring an OPDS server.

Web Interface

The browser UI has four primary pages.

Home

The Home page shows firmware status, network mode, IP address, device type, uptime, and free heap.

File Manager

The File Manager page can:

  • Browse SD-card folders
  • Upload files, using WebSocket upload when available and HTTP upload as a fallback
  • Optimize EPUB files before upload
  • Create folders
  • Download files
  • Rename files
  • Move files into existing folders
  • Delete one or more selected files or empty folders

Existing files with the same name are overwritten by uploads. When EPUB files are overwritten, moved, renamed, or deleted through the web server, the matching book cache is cleared so stale metadata is not reused.

EPUB Optimization

When uploading an EPUB, the upload dialog can optimize the file in the browser before sending it to the reader. This is useful for image-heavy books that are too large or memory-sensitive for the device.

The default optimization path converts images for e-ink reading, limits them to the target device size, saves them as JPEG at 85% quality, and applies basic EPUB repairs such as safer SVG handling. Advanced Mode lets you pick the target device, JPEG quality, image split or rotation handling, and split overlap.

Optimization changes the EPUB file contents before upload. Note: if you use hash-based KOReader sync, this will break the syncing because it changes the epub and therefore the hash. If optimization fails, the uploader falls back to sending the original file.

Settings

The Settings page exposes many firmware settings in the browser. It also has cards for:

  • Saved Wi-Fi networks
  • OPDS servers

Passwords are accepted when adding or editing entries, but saved passwords are not returned by the API.

Fonts

The Fonts page lists installed SD-card font families and lets you upload .cpfont files. Upload files from one font family at a time. The server validates the font family name, filename, and .cpfont magic bytes before accepting the upload.

Installed fonts appear in Settings > Reader > Font Family after the font registry refreshes.

Command Line Use

Power users can use curl, WebDAV clients, or WebSocket clients while the web server is running.

Endpoint details are documented in webserver-endpoints.md.

Security Notes

  • The HTTP server runs on port 80.
  • The WebSocket upload server runs on port 81.
  • There is no authentication.
  • Anyone on the same network can access the web interface while it is running.
  • The server stops when you exit File Transfer or Calibre Wireless mode.
  • Hotspot mode creates an open network for connectivity fallback; disconnect when done.

Tips

  1. Use Create Hotspot when no trusted network is available.
  2. Prefer crosspoint.local when available, but keep the displayed IP address as a fallback.
  3. Move closer to the router if upload progress stalls in Join Network mode.
  4. Upload custom fonts through the Fonts page or copy them to /.fonts/ or /fonts/ on the SD card.
  5. Exit File Transfer mode when finished to conserve battery.
This site uses Just the Docs, a documentation theme for Jekyll.