How to share text and files between devices
Follow a reliable transfer workflow, diagnose mismatched room keys, choose the right tool, and clean up shared content.
Read guideCopyPaster knowledge base
Safer, more reliable device sharing
CopyPaster is simple to operate, but the network model matters. These guides explain how to complete transfers reliably and how to decide whether a piece of information is suitable for a room based on a shared public IP address.
Public-IP rooms: privacy and safe use
Understand how room membership works, why shared networks matter, which information should never be uploaded, and how to limit exposure.
Read guideUse the tool for temporary handoffs
The service is best suited to short-lived material such as a public URL, a non-confidential note, an image intended for sharing, or a document that does not contain private information. It is not a replacement for an authenticated cloud drive, encrypted messenger, password manager, or long-term document store.
A matching room key confirms that two browsers reached the same room. It does not identify the people using that room or guarantee that no other device can access it. Review the privacy guide before using CopyPaster on an office, school, hotel, airport, café, mobile carrier, or VPN connection.
When a transfer does not work
Nearly every failed transfer comes down to the same cause: the two browsers are not in the same room. Compare the room key shown at the top of each device. If the keys differ, the devices are leaving the internet through different public addresses — a phone that dropped to mobile data, a laptop on a corporate VPN, or a guest network that isolates clients from one another. Put both devices on the same connection and the keys will match.
If the keys match but content is missing, refresh the page. Large networks sometimes sit behind carrier-grade NAT that rotates addresses, which moves you to a new room mid-session and leaves the old content behind. The share-text guide walks through this in detail.