Same Product, Separate Accounts: Why Feishu and Lark Users Can't Add Each Other

A Counterintuitive Observation

Tencent Meeting and VooV Meeting share the same underlying platform. Feishu and Lark share the same underlying platform. Microsoft Teams uses the same codebase in mainland China as it does everywhere else. Yet in all three cases, users in China and users overseas either cannot communicate with each other at all, or can only do so in very limited ways.

What makes this counterintuitive is that, from the user’s perspective, a unified account system is the better choice. A Tencent Meeting user should be able to join a VooV Meeting call directly. A Feishu user should be able to message a Lark user directly. A Teams user opening the app in China should land in the same workspace. The same logic applies to enterprises: a company with offices in both China and abroad should naturally be able to use one collaboration tool across the whole organization.

But that’s not how it works. Why?

What makes this even more interesting is that not every vendor makes this choice. Apple’s FaceTime offers a telling contrast: Apple has data centers in Guizhou, and Chinese users’ iCloud data and encryption keys are stored in facilities operated by the state-owned enterprise GCBD — but the Apple ID is unified globally. A user in Beijing and a user in San Francisco can make a FaceTime call seamlessly using their respective Apple IDs, with no extra configuration required. Weixin/WeChat offers another instructive comparison: Weixin (the mainland China version) and WeChat (the international version) are the same app, operated by different entities within the Tencent group, with different backend infrastructure and different terms of service — yet users on both sides can chat and make voice calls with each other.

What factors determine whether a product ends up with a unified account system or a split one? Why do some products manage to maintain a unified account layer even when they are required to store data locally?

The Landscape First: What’s Split, What Isn’t

Before asking “why,” it helps to establish the facts. We looked at 12 mainstream collaboration and communication products and found they fall along a continuous spectrum, from “fully split” to “fully unified.” A more useful framework, though, is to assess each product along three dimensions: whether the account system is independent, whether the operating entity is independent, and whether data storage is isolated.

Independent account system, independent operating entity, fully isolated data. This is the most thoroughly fragmented category. Feishu and Lark are the canonical example: Feishu data resides in mainland China, Lark data is stored on AWS in Singapore, the US, and Japan, and Lark is operated by an independent legal entity registered in Singapore. The two systems have completely separate account structures — Feishu users and Lark users cannot add each other as contacts, cannot message each other, and cannot join the same workspace. Microsoft Teams in China falls into the same category: operated independently by 21Vianet, with a separate Azure AD tenant, a separate admin portal (portal.partner.microsoftonline.cn), and separate endpoint domains (.partner.outlook.cn, .sharepoint.cn). Users in China must register a new 21Vianet tenant and cannot use a global tenant. Cisco Webex China is similarly operated independently by a local partner, TCL/Skytech, with the China cluster physically isolated from the global infrastructure and encryption keys generated within China.

Interoperable accounts, separate operating entities, data routed by region. The defining feature of this category is that users can communicate across regions, but each side is subject to different laws and different terms of service. Weixin and WeChat fall here. They are the same app, operated by different Tencent subsidiaries, with different backend infrastructure (Weixin data stored in mainland China, WeChat data stored in Singapore and Hong Kong) and different terms of service. Users are automatically segmented by the phone number used to register: mainland China numbers produce a Weixin account, all other numbers produce a WeChat account. The two can exchange messages, make voice calls, and see each other’s Moments — but when they do, both parties become subject to the other side’s terms of service. Notably, when prohibited content appears in a mixed group chat, messages are split into “two virtual groups” — domestic users cannot see certain messages from overseas users, and vice versa. VooV Meeting and Tencent Meeting work similarly: the same underlying platform, with the brand automatically switching based on the user’s IP, but a shared meeting ID system that allows a VooV user overseas and a Tencent Meeting user in China to join the same call.

Same product with regional restrictions, no separate account system. Zoom falls here. Chinese users and overseas users use the same Zoom client and the same account system; Chinese users’ data is simply forced to route through Chinese data centers. Free-tier users in China are blocked (error code 13215); paid users can use the service normally. Zoom has not built a separate “China edition” — it has applied geofencing to a single product.

Unified account system, data stored by region, invisible to users. Apple’s FaceTime and iMessage are the prime example. The Apple ID is globally unified: wherever you register, whatever region you set, your Apple ID is the same worldwide. If your region is set to mainland China, your iCloud data migrates to the GCBD data center in Guizhou, and encryption keys are stored in the same facility — something that does not happen in any other region, where keys are stored on Thales hardware security modules in the United States. But FaceTime itself is unaffected: a user in Beijing and a user in San Francisco can make a video call using their original Apple IDs without any friction. Apple’s choice here was to implement regional isolation at the data storage layer while maintaining a unified identity and communication layer.

Fully blocked or withdrawn, no regional version exists. Slack terminated direct service to mainland China, Hong Kong, and Macau in April 2026. Google Meet has been fully blocked since 2010. Discord has been blocked since July 2018. WhatsApp has been blocked since 2017. These products made no localization concessions and built no “China version.”

Why the Same Company Doesn’t Share One Account System

Back to the central question. Feishu and Lark are built by the same company (ByteDance), on the same codebase. VooV Meeting and Tencent Meeting are built by the same company (Tencent), on the same codebase. From a technical and user-experience standpoint, a unified account system is the clearly superior solution. So why not build one?

The answer is not a single cause but the compounded result of four layered mechanisms. Each layer, taken alone, is insufficient to explain the full picture — but stacked together, they explain why some products split and others don’t.

Layer One: Content Moderation and Real-Name Requirements Create the Most Direct Structural Conflict

This layer is often overlooked in discussions of data regulation, but it may be the most immediate driver of product fragmentation.

Chinese internet regulations require all platforms providing information publishing, instant messaging, and similar services to maintain content moderation mechanisms. The Cybersecurity Law (effective 2017, revised 2025) requires network operators to manage user-published content and prohibit the transmission of illegal information. The Internet Information Service Algorithmic Recommendation Management Provisions (effective 2022) require algorithm-driven platforms to maintain content identification libraries and filter out illegal or harmful content. The Internet Information Service Deep Synthesis Management Provisions impose similar review obligations on AI-generated content. Consequences for non-compliance include warnings, fines, suspension, site closure, and license revocation.

More consequential still is the real-name requirement. The Cybersecurity Law requires network operators to verify users’ real identities before providing information publishing or instant messaging services. The 2026 revision tightened enforcement further. A platform serving both Chinese and overseas users faces an impossible triangle: China requires real-name verification, overseas users generally will not accept it, and a unified platform means either forcing overseas users into real-name registration (a user experience catastrophe) or waiving it for Chinese users (illegal).

The practical effect of these requirements on actual products goes much deeper than “where the data is stored.” In the case of Weixin/WeChat, empirical research from the University of Toronto’s Citizen Lab has demonstrated that when international WeChat users and mainland-registered Weixin users are in the same group, messages sent by international users pass through China-side moderation engines before being delivered to domestic users — sensitive content is silently blocked or dropped (the sender sees the message as sent, but the recipient never receives it). Liu Lipeng, a former Sina content moderator, put it more bluntly: apart from end-to-end one-on-one chat, virtually everything on Weixin/WeChat runs through the Weixin protocol — “the moment you agree to re-sign the terms, you’re back on the Chinese version.”

This is why mixed group chats between Weixin and WeChat users produce the “virtual group bifurcation” phenomenon: domestic users cannot see some overseas users’ messages, and vice versa. This is not a technical limitation — it is the engineering implementation of a moderation boundary. Once messages flow between two moderation systems, the platform cannot simultaneously satisfy both sets of legal requirements, so the message streams are cut at the infrastructure level.

For enterprise collaboration products, content moderation requirements exist in a different form. These platforms don’t generally publish content to the public, but they do store chat logs, meeting transcripts, shared files, and similar content. If that content sits on a unified platform accessible across regions, the platform faces a dilemma: Chinese regulators may demand access to certain chat logs or transcripts, while users and laws in other regions may prohibit exactly that access. Splitting accounts and infrastructure is the cleanest way to avoid this bind.

Layer Two: Data Export and Licensing Requirements Define the Boundaries of the Possible

This layer determines whether data can cross borders and what licenses a service requires.

China’s Personal Information Protection Law (PIPL) imposes conditions on cross-border transfers of personal information (security assessments, standard contracts, etc.). The Data Security Law restricts exports of important data and the provision of data stored within China to foreign law enforcement. The Telecommunications Regulations place value-added telecommunications services under a licensing regime. In practice, this means: a company that wants to legally operate a collaboration platform in China with user data stored there must keep that data on infrastructure within China, and typically must have a local operating entity that holds a value-added telecommunications business license.

On the US side, OFAC sanctions prevent selling services to certain countries, and BIS/EAR export controls restrict providing encryption-related technology to certain end users. But these rules are more about “which countries are off-limits” and “which customers need a separate environment” than requiring a standalone product for each region. The stronger driver of segmentation in the US context is government and regulated-industry cloud: FedRAMP requires platforms handling sensitive federal information to operate in an authorized environment; AWS GovCloud is a physically and logically isolated US sovereign region, operated by US citizens on US soil.

The EU’s GDPR requires adequacy decisions, Standard Contractual Clauses, or Binding Corporate Rules for transfers of personal data outside the EEA. The logic is “transfer is allowed, but you must demonstrate compliance” — not an outright prohibition. But the ongoing burden of transfer impact assessments, customer negotiations, and regulatory inquiries creates significant operational overhead.

The legal constraints in all three regions point in different directions, but their combined effect is the same: when a product serves users across multiple regions simultaneously, the three questions of where data is stored, what qualifications the operating entity holds, and how cross-border transfers are made compliant become extremely complex.

Layer Three: Procurement Compliance Requirements Demand Environmental Isolation

Even when the law does not require a separate product, the procurement requirements of large enterprise and government customers themselves drive environmental isolation.

Government customers require FedRAMP authorization. Financial customers require local data centers and local key escrow. Multinationals’ legal departments require simultaneous compliance with China’s PIPL, the US SOX Act, and the EU’s GDPR. When these procurement requirements hit the infrastructure layer, they become independent regions, independent administrator populations, independent encryption implementations, and independent audit boundaries.

Azure China, AWS China, AWS GovCloud, and Zoom for Government are all products of this layer. Vendors are not necessarily legally compelled to build a separate product — but without one, they cannot get onto government procurement lists or into large enterprise vendor pools.

Layer Four: Vendors Choose Hard Isolation After Running the Numbers

This is the most critical and most frequently overlooked layer. Law and procurement compliance set the boundary conditions, but how to operate within those boundaries is the vendor’s own choice.

A separate account system means not having to reconcile the conflict between cross-region real-name requirements (China requires real-name; most other regions do not). Independent feature release cadences mean not having to evaluate each new feature individually for compliance on the China version. Independent pricing means regional price differentiation is possible (VooV Meeting began charging in 2024 while Tencent Meeting remained free in China). Independent support teams mean customer service staff never encounter data they shouldn’t see. Not implementing cross-region tenant interoperability means not having to deal with the legal conflicts around cross-region eDiscovery and data retention.

In other words, the law only requires “satisfying certain conditions” — but there are multiple ways to satisfy them. Case-by-case compliance evaluation on a unified product may have lower short-term costs, but a separate product has lower long-term operational costs: every new feature added, every customer complaint handled, every regulatory inspection navigated does not require reassessing cross-region implications.

Apple’s FaceTime chose a different path: isolation at the data storage layer (China-region data stored at GCBD, encryption keys stored in the same facility), while maintaining a unified account and communication layer. This means Apple must continuously manage the compatibility between a globally unified identity system and a China-specific data storage arrangement — not a low-cost operation. Apple can sustain this approach partly because its business model does not depend on enterprise compliance procurement (FaceTime is not an enterprise collaboration platform and does not need FedRAMP-type authorization), and partly because its user base and brand power give it sufficient leverage to maintain this complex intermediate state.

Feishu and Lark chose fragmentation for reasons that operate on multiple dimensions simultaneously. On the data side: Feishu user data must stay in China, and Lark users need assurance that their data is not in China. On the moderation side: Feishu, as a product for Chinese users, must deploy a content moderation system that satisfies Chinese regulations — and Lark users neither need nor should be subject to that system. On the identity side: Feishu users must complete real-name verification; Lark users generally do not. These requirements are incompatible at the account layer. If Feishu and Lark users could add each other, Feishu user data could appear in the Lark environment through contacts, forwarding, and group chats — and vice versa. Lark users’ communications could also be forced through China’s moderation engine. To thoroughly isolate data, moderation, and identity, account isolation is a prerequisite.

Weixin and WeChat chose a different middle path: separate operating entities, separate backends, separate terms of service, but with user-to-user interoperability. This means a Weixin user and a WeChat user can message each other — but at the moment of interoperation, both parties become subject to each other’s terms. The elegance of this design is that it avoids the total isolation of the Feishu/Lark model while using cross-applied terms of service to handle compliance. But the costs are visible: the message bifurcation in mixed group chats (where domestic users cannot see some overseas messages) shows that this interoperability is not frictionless and does not constitute genuine unification.

Tencent Meeting and VooV Meeting chose a middle road: unified infrastructure, split branding, shared meeting ID space. This makes cross-region meetings possible while keeping feature release cadences and pricing strategies independently adjustable across the two brands. The cost of this approach is that if regulatory requirements tighten in the future, Tencent will need to add more cross-region data controls to the underlying platform — otherwise the data flows created by the shared meeting ID system could become a compliance liability. The Weixin/WeChat interoperability model faces a similar tension: users can communicate across regions, but the message bifurcation in mixed group chats indicates that some level of separation has already been implemented at the infrastructure level, with bridging preserved only at the communication surface.

Where Cross-Region Interoperability Ends

After fragmentation, whether you can still make a cross-region video call depends on what the product has done at the media plane versus the data plane.

The media plane carries video streams, audio streams, and screen sharing — real-time transmissions that are instantaneous, non-persistent, and gone when the session ends. The data plane covers user directories, chat histories, meeting recordings, whiteboard content, transcripts, audit logs, retention policies, and eDiscovery data — persistent, searchable, and subject to stronger legal constraints.

Most products that have fragmented cut the data plane more thoroughly than the media plane. Legal constraints primarily apply to persistent data. Real-time video streams are also regulated, but the fact that “the data ceases to exist when the meeting ends” makes them less legally sensitive than recording files and chat logs.

Teams’ cross-cloud interoperability is currently the most fully realized among enterprise collaboration products. Microsoft’s official documentation explicitly supports cross-cloud meetings, chats, and calls between 21Vianet tenants and global tenants, configured by administrators on both sides enabling Cross-Cloud External Access and Entra B2B. But interoperability ends at the data plane: the two sides can meet together, but cannot share channels, cannot search across clouds, and cannot share a recording library or eDiscovery scope. Data remains in each respective cloud; media is routed through each respective cloud.

Zoom’s interoperability is more restricted. Paid China-region users can join global meetings (because meeting IDs are universal), but Zoom has no formal cross-cloud collaboration architecture like Teams — interoperability relies more on the universal meeting ID system than on a purpose-designed cross-region bridge.

Webex China and Feishu/Lark have no interoperability at all, because both the operating entities and account systems are independent.

A practical rule of thumb: look at whether the operating entities are independent. If they are, cross-region interoperability is something the vendor must deliberately engineer — and they may not have. If the operating entity is the same but there has been brand or routing segmentation, interoperability is typically easier to achieve, because the underlying control plane remains unified.

A Decision Framework

The next time you encounter a product with a China edition, international edition, European edition, or Gov edition, five questions can help you assess how deeply it is fragmented and why.

Has the operating entity changed? If the counterparty to the contract, the invoicing entity, the customer service provider, and the data processor have all changed, this is the strongest signal of independence. AWS China, Azure China, and Webex China all fit this pattern. Apple iCloud China is operated by GCBD, but the Apple ID still belongs to Apple — and that is the key reason Apple can maintain a unified account system.

Are the account system and control plane independent? If you must re-register, cannot use your global account, and the API endpoints and admin portals are different, this is not a reskin — it is a separation at the control plane boundary. Feishu/Lark is the most thorough example of this.

Does persistent data cross regions? The video stream itself is often not the most sensitive element. The things worth watching are the persistent data: user directories, chats, recordings, transcripts, audit logs, encryption keys, and support tickets — and whether these remain within their respective regions. The fact that Apple stores keys and data in the same facility in the China region, while keeping them separate in every other region, itself illustrates how regional compliance can affect encryption architecture.

Who does the regional segmentation primarily serve? For customers within China, start with local operating entities, licenses, and export assessments. For US government or regulated customers, start with FedRAMP, US Persons only, and sanctions screening. For large EU enterprises or public sector organizations, start with GDPR transfer obligations and data-residency procurement preferences.

Where does interoperability end — at the media layer or the data layer? Being able to meet across regions means the network and media plane have not been severed. Being unable to share tenants, recording libraries, retention policies, or global search means the data and governance layers have been cut. Teams can meet across clouds but cannot share recordings across clouds — that is the classic pattern of an open media plane and a closed data plane.

Trends

The global SaaS delivery model is shifting from “register once, use everywhere” to a stratified supply structure. This is not an isolated phenomenon in one region — it is a trend driven by multiple forces acting simultaneously across multiple dimensions.

China, the United States, and the European Union each impose constraints along different dimensions: China emphasizes data export controls and operating licenses; the US emphasizes export controls and government cloud; the EU emphasizes transfer obligations and procurement preferences. The combined effect of all three is to make “globally unified products” progressively more expensive to operate and “regionally split” approaches progressively more economical.

For enterprises that depend on global SaaS, this means the default assumptions of the past — register one account, use it anywhere in the world, accept one global set of terms — are being steadily eroded. Slack’s 2026 withdrawal from China, Zoom’s blocking of free-tier users in China, Microsoft’s operation of a separate 21Vianet cloud for China, and ByteDance’s construction of Feishu and Lark as two entirely independent systems all share the same underlying pattern despite having different triggering mechanisms: when a platform’s compliance cost in a given region exceeds its revenue from that region, it will choose to split or exit — and customers’ data and business continuity are secondary considerations in that calculus.

Apple’s FaceTime demonstrates that it is possible to maintain a unified account layer while implementing regional isolation at the data layer — but that approach has prerequisites: the product must not depend on enterprise compliance procurement, and the vendor must have sufficient market position to sustain a complex cross-region operating architecture. For most enterprise collaboration products, neither condition holds, and splitting accounts remains the more economical choice.

Key Sources