WhatsApp enabled third-party chat interoperability for users in the European Economic Area on Saturday, allowing messages to and from services that have signed Meta's interoperability agreement and passed its technical certification. Three partners are live: the German messenger Ginlo, the Swiss service Threema, and a federated Matrix bridge operated by Element. Users opt in through a settings toggle that is off by default, and third-party conversations appear in a separate inbox section rather than mixed with WhatsApp threads. The Digital Markets Act required this capability by March 2024 and the intervening period has been spent on protocol specification, security review, and a long argument about spam.
How the connection works
Meta published a specification built on the Signal protocol for end-to-end encryption, with a separate layer handling identity, delivery, and metadata. A third-party service runs a bridge that speaks Meta's protocol on one side and its own on the other, and message content is encrypted from the sending client to the receiving client, with the bridge unable to read it if the third party implements correctly. That last clause is doing enormous work, because Meta cannot verify what a partner does with plaintext on its own side.
Identity is handled by phone number, which is WhatsApp's identifier and which Threema in particular does not use natively. Threema's implementation asks users who want interoperability to associate a phone number, which is a meaningful privacy concession for a service whose entire pitch is not requiring one. The company made it optional and clearly labeled, and its own forums have been unhappy about it, which illustrates how interoperability with a phone-number-based network pulls other designs toward the same model.
What users actually experience
Turning on the feature and adding a Threema contact took about four minutes, most of it spent finding the setting. Messages deliver in under a second. Text works. Images and voice notes work with a quality reduction from transcoding. Replies and reactions work. Group chats do not, and will not until a later phase Meta has scheduled for the first quarter of 2027. Voice and video calls are not part of the requirement and are not supported.
The separate inbox is the design choice that will determine adoption. Third-party conversations sit under a heading that requires an extra tap to reach, and notifications are labeled with the source service. Meta says this prevents confusion about which conversations carry WhatsApp's security guarantees. Competitors say it buries the feature, and the European Commission has asked Meta to justify the placement, which suggests at least one regulator agrees.
The story is rarely the launch. It is what breaks, what ships, and who owns the mess at 2 a.m.
Why the large messengers are absent
Signal has said publicly it will not interoperate, on the grounds that connecting to a network with weaker metadata protection undermines what Signal offers, and that its users' privacy expectations cannot be maintained across a bridge it does not control. That position has been consistent since the DMA was drafted and is broadly respected even by people who wish Signal would reconsider.
Telegram has not commented in any detail. Apple's iMessage was excluded from the DMA's messaging obligations after the Commission accepted that it did not meet the user thresholds in Europe, a determination that surprised many and that has been challenged. Google's RCS implementation is technically interoperable already through the carrier standard and sits outside this framework entirely. The result is that the two largest potential partners are absent and the feature connects WhatsApp to services with a combined user base a fraction of a percent of its own.
The spam problem everyone predicted
The technical review process took two years largely because of abuse. WhatsApp's spam defenses depend on signals from its own client and network, and a message arriving through a bridge carries none of them. Meta's answer is a reputation system per partner: each bridge gets a rate budget, abuse reports count against it, and a partner exceeding thresholds gets throttled or disconnected. Partners must also implement their own abuse handling and report metrics.
That structure gives Meta considerable discretionary power over competitors, which is exactly the concern the DMA was written to address. A partner throttled for abuse has limited recourse and Meta controls the evidence. The Commission's implementing guidance requires an appeals process and Meta has published one. Whether it functions will only become visible when a partner is actually disconnected, which has not happened yet.
Whether this accomplishes anything
The DMA's theory was that interoperability lowers switching costs, letting a user leave a dominant messenger without losing contact with everyone on it. That theory requires alternatives worth switching to and a user experience good enough that the bridge is not a downgrade. Neither condition is met today, and the separate inbox plus missing group chat makes the bridged experience clearly worse than the native one.
The more plausible path to value is slower. If a European messenger builds something genuinely better and interoperability means adopting it costs nothing socially, the feature matters. That is a multi-year proposition and it depends on someone building that product. For now the honest assessment is that a significant regulatory intervention has produced a feature that almost nobody will use, which is a common outcome for structural remedies and not a reason to conclude they never work.
Skarvonix will keep following this beat with reporting grounded in how systems behave outside the launch keynote.
- Privacy
