WhatsApp could let users message without their phone.
As it stands, the Facebook-owned instant messaging service is linked to a phone, and both the desktop and web apps need the device to be connected.
However, an upcoming new feature will allow people to send and receive messages "even if your phone battery is dead".
The company has confirmed that up to four devices - including PCs and tablets - can be used.
Initially, a "small group of users" will get the feature as part of a beta test, with the team then making tweaks before a full roll-out.
WhatsApp clarified that end-to-end encryption will still work under the new system.
In a blog post, the team said: "Each companion device will connect to your WhatsApp independently while maintaining the same level of privacy and security through end-to-end encryption that people who use WhatsApp have come to expect.
"Importantly, we have developed new technologies to maintain end-to-end encryption while still managing to sync your data — such as contact names, chat archives, starred messages, and more — across devices.
"To achieve this, we had to rethink WhatsApp’s architecture and design new systems to enable a standalone multi-device experience while preserving privacy and end-to-end encryption."
WhatsApp chief Will Cathcart admitted he was "very excited" to be launching the beta for the new feature, and noted they have "been working on this for a long time".
