WhatsApp Working on Interoperability With Other Encrypted Messaging Apps

As part of its compliance with the EU's Digital Markets Act (DMA) legislation, WhatsApp is putting the final touches to introducing platform interoperability with other encrypted messaging apps.

In September, EU lawmakers designated WhatsApp parent company Meta as one of six so-called "gatekeepers," along with Google, Amazon, Apple, ByteDance, and Microsoft, giving them six months to begin opening up their core platform services to others.

The DMA comes into full effect in March 2024. That leaves just a few weeks for WhatsApp and others to bring their services into compliance. However, Wired reports that WhatsApp has actually been working on interoperability for the past two years, and its work is only partially motivated by the looming DMA.

According to Dick Brouwer, an engineering director at WhatsApp, interoperability will initially focus on (non-SMS) text messaging, sending images, voice messages, videos, and files between two people. Calls and group chats will come in the next few years, as per the EU's rules.

Brouwer says users who opt-in to interoperability will see messages from other apps in a separate section at the top of their WhatsApp inbox. "The early thinking here is to put a separate inbox, given that these networks are very different," Brouwer says. "We cannot offer the same level of privacy and security," he told Wired.

To send messages, third-party apps will need to encrypt content using the Signal Protocol, and then be packaged using XML, in compliance with the platform's existing client-server architecture. Apps will also need to connect to WhatsApp's servers to receive messages.

WhatsApp will also allow other apps to use different encryption protocols if they can demonstrate they reach the security standards that WhatsApp outlines in its guidance. Third-party developers will also have an option to use a proxy between their apps and WhatsApp's servers. This could give developers more flexibility by removing the need for them to use WhatsApp's client-server protocols, but it also increases potential attack vectors, cautions Brouwer.

Third-party chats appearing in WhatsApp could yet be some way off, however. Brouwer says the company is still working on the interoperability features and the level of support it will make available for companies wanting to integrate with it. Messaging companies that want to interoperate with WhatsApp will need to sign an agreement with the company and follow its terms. "Nobody quite knows how this works," Brouwer told Wired. "We have no idea what the demand is."

The full details of the plan, which will apply to both WhatsApp and Messenger, will be published by Meta in March, and the company will have several months to implement it.

"There's real tension between offering an easy way to offer this interoperability to third parties whilst at the same time preserving the WhatsApp privacy, security, and integrity bar," Brouwer admitted. "I think we're pretty happy with where we've landed," he added.