Why Messaging Apps Still Struggle With True Interoperability

Fact-checked by the SnapMessages editorial team

Messaging app interoperability — the ability to send messages across different platforms without switching apps — has been a persistent technical and political failure for over a decade. According to Statista’s 2024 global messaging data, the top five messaging platforms collectively serve more than 5 billion monthly active users, yet none of them communicate natively with each other.

This matters now because regulators in the EU and UK are pushing harder than ever for open standards — and the technical reality is proving far more complicated than any single law can fix.

What Is Messaging App Interoperability and Why Does It Still Not Exist?

Messaging app interoperability means a user on WhatsApp can message someone on Signal or Telegram without either party downloading a new app. It does not exist at scale today because each platform was built on proprietary protocols designed to lock users in, not to connect outward.

WhatsApp uses its own implementation of the Signal Protocol. iMessage runs on Apple Push Notification Service infrastructure that is deliberately closed. Telegram uses its custom MTProto encryption. These are not just different roads — they are different transportation systems entirely. Bridging them requires agreement on a shared protocol, and no dominant platform has financial incentive to make switching easier for its users.

The closest the industry has come to a universal standard is Matrix, an open-source protocol maintained by the non-profit Matrix.org Foundation. Matrix supports federated, encrypted messaging across servers — but adoption among mainstream consumer apps remains minimal. If you want to understand how cross-platform communication works at a lower level today, our breakdown of how cross-platform messaging works between iPhone and Android covers the current infrastructure clearly.

What Does the EU Digital Markets Act Actually Require From Messaging Platforms?

The EU’s Digital Markets Act (DMA) is the most significant regulatory intervention in messaging history. It requires designated “gatekeepers” — platforms with over 45 million EU monthly users and a market cap above 75 billion euros — to open their messaging infrastructure to third-party interoperability upon request.

Meta, Apple, and Google were designated as gatekeepers under the DMA in 2023. The first interoperability obligations for one-to-one messaging took effect in March 2024, according to the European Commission’s DMA enforcement page. Group messaging and voice/video call interoperability carry later deadlines — 2025 and 2027 respectively.

How Are Platforms Responding to DMA Mandates?

Meta announced a third-party interoperability API for WhatsApp in 2024. However, critics including the Electronic Frontier Foundation have flagged that the implementation terms allow Meta to set conditions that could make integration technically burdensome for smaller rivals. Apple’s iMessage, classified under a different gatekeeper category, initially argued it should be exempt — a position the European Commission rejected.

Compliance has been slow and partial. The DMA does not specify which technical protocol platforms must use, only that they must enable interoperability. That ambiguity gives gatekeepers wide latitude to propose solutions that technically comply but practically obstruct competition.

Why Does End-to-End Encryption Make Interoperability So Technically Hard?

End-to-end encryption is the single biggest technical barrier to messaging app interoperability. When encryption keys are generated and stored on user devices, bridging two platforms means agreeing on how each system handles key exchange, verification, and forward secrecy — and that agreement is extraordinarily difficult to achieve without weakening security.

Signal’s protocol, widely regarded as the gold standard, uses Double Ratchet encryption combined with X3DH key agreement. WhatsApp licensed this protocol but implemented it in a closed environment. If WhatsApp were to accept messages from an outside platform, it would need to verify that the outside platform’s key management is equally trustworthy. There is currently no audited, universally accepted standard for cross-platform key federation.

This is why security researchers warn that forced interoperability, if poorly implemented, could create new attack surfaces. A compromised third-party client could be used to intercept messages that were presumed secure. Understanding these risks is especially important for users who already think carefully about securing their messaging apps before international travel.

How Do Major Messaging Platforms Compare on Interoperability Readiness?

Not all platforms are equally resistant to interoperability. Open-protocol apps like Element (built on Matrix) and XMPP-based clients are already interoperable by design. The problem is that they hold a tiny fraction of global users compared to closed giants.

RCS (Rich Communication Services) represents one partial success story. Apple adopted RCS on iPhones in 2024 after years of resistance, enabling richer cross-platform messaging between iPhone and Android users. However, RCS encryption is not end-to-end by default across all carriers — a significant limitation. Our detailed coverage of how RCS is replacing traditional texting on iPhones explains what changed and what still falls short.

What Business Incentives Are Actively Blocking Messaging Interoperability?

Business model lock-in is as powerful a barrier as any technical limitation. Each major platform profits from keeping users inside its ecosystem. WhatsApp drives Meta’s advertising and payments strategy. iMessage is a key differentiator in Apple’s premium device ecosystem. Telegram monetizes through premium subscriptions tied to its proprietary feature set.

Opening up to interoperability reduces switching costs — the friction that keeps users from moving to a competitor. Lower switching costs mean lower user retention, which directly threatens platform revenue. This is why interoperability mandates face intense lobbying: the financial stakes are measured in billions of dollars of ecosystem value, not just messaging feature parity.

The network effect compounds this. A platform with 2 billion users like WhatsApp is more valuable precisely because everyone is already there. Interoperability would neutralize that advantage, allowing a small secure app to communicate with WhatsApp’s entire user base without offering WhatsApp anything in return. Understanding how AI features are now being woven into this closed ecosystem dynamic is also worth tracking — see our analysis of how AI is being used inside messaging apps right now.

There is also a security accountability problem. If a third-party app sends a malicious message through an interoperability bridge, who is liable — the originating platform or the receiving one? No regulatory framework has clearly resolved this yet, giving platforms additional cover to resist compliance.

Frequently Asked Questions

Can I already send messages from WhatsApp to Signal in 2025?

No. As of July 2025, direct messaging between WhatsApp and Signal is not possible for general users. WhatsApp has published a limited interoperability API for EU-based third-party developers under DMA obligations, but no consumer-facing cross-platform chat between these two apps exists yet.

What is the Digital Markets Act and how does it affect messaging apps?

The Digital Markets Act is EU legislation that designates large tech platforms as “gatekeepers” and imposes interoperability requirements on their messaging services. Platforms with over 45 million EU monthly users must allow third-party apps to connect to their messaging infrastructure upon request. Enforcement began in March 2024.

Does RCS solve the messaging interoperability problem?

RCS solves carrier-level interoperability — Android and iPhone users can now exchange RCS messages with richer features than SMS. However, RCS does not solve app-to-app interoperability, and end-to-end encryption under RCS is not universally implemented across all carriers and devices.

Why does end-to-end encryption make cross-platform messaging harder?

End-to-end encryption requires both platforms to agree on how encryption keys are generated, stored, and verified. When platforms use different protocols — like Signal Protocol versus MTProto — bridging them without compromising security requires a trusted intermediary layer that does not yet exist at scale.

Which messaging app is most open to interoperability right now?

Element, built on the open Matrix protocol, is the most interoperable mainstream messaging app available today. It can federate with any other Matrix-compatible server. XMPP-based clients also support interoperability, though both have significantly smaller user bases than WhatsApp or iMessage.

Is messaging app interoperability a privacy risk?

It can be, if implemented poorly. A compromised or lower-security third-party client connecting via an interoperability bridge could expose messages that users assumed were fully encrypted. Security experts including those at the Signal Foundation recommend that any interoperability standard must mandate equivalent encryption and key verification requirements on all connected platforms. For broader context, understanding how to build a personal digital security routine helps users make informed choices regardless of which platform they use.