WhatsApp to allow cross-app chatting soon: Here’s how

According to Brouwer, the company has been working on interoperability for around two years now. The move comes as WhatsApp parent company Meta has been designated a 'gatekeeper' company under the EU's Digital Markets Act, which requires it to open up its messaging services within six months.

Interoperability will allow WhatsApp users to exchange messages, images, videos and files with people on other messaging platforms. Brouwer said it will focus initially on one-on-one messaging rather than group chats or calls. Users will have to opt in to activate the feature. Importantly, WhatsApp will keep messages from other apps separate - they will appear in a 'third party chats' section rather than the main inbox. This is to maintain WhatsApp's high privacy standards.

Enabling cross-platform messaging is technically complex, especially for encrypted apps like WhatsApp. Different platforms use different protocols and have varying privacy standards. Brouwer admitted there is "real tension" in opening up access while preserving security. WhatsApp will publish technical details in March for third parties to integrate with its system. Companies will have to sign an agreement and follow WhatsApp's terms to connect their apps.

WhatsApp would prefer third parties use the same Signal encryption protocol as WhatsApp. This is publicly used by apps like Google Messages and Skype. For sending messages, apps will have to encrypt via Signal and package content into XML message formats. To receive messages, they'll need to connect to WhatsApp's servers.

Brouwer said this architecture, using WhatsApp's existing client-server system, is the "best approach". WhatsApp has been collaborating with other companies. It will document its protocols to let third-party clients integrate directly. There will also be options for proxies between their apps and WhatsApp’s server if developers want more flexibility.

So far, WhatsApp has not revealed which platforms might link up. Major messaging apps like Telegram, Signal, Snap and Google did not comment on plans to enable WhatsApp interoperability. Given the technical complexities, it may take time for third parties to launch integrations after WhatsApp publishes its March guidance.

Under EU rules, interoperability has to launch within just six months. However, it's unclear if it will be Europe-only initially. WhatsApp did not clarify if the feature will be available globally. When enabled, a "third party chats" section will appear for users, as previously spotted in WhatsApp beta versions by WABetaInfo - although this page isn’t directly accessible or functional at the moment.

Apple's iMessage may also have to offer interoperability under the EU's Digital Markets Act. However, Apple has not commented on its plans. In the US, it faces separate scrutiny about keeping iMessage as a closed platform. Opening it up could facilitate communication between iOS and Android users.

The bottom line is that WhatsApp's planned changes are significant. Users won't need multiple apps to message different contacts if services interlink. However, take-up depends on third parties integrating, which may take time due to complexities. Any privacy risks that may arise from lower security standards also need addressing.