What is cross-company messaging integration?

Cross-company messaging integration is the ability for two separate organizations — each using their own enterprise chat platform — to communicate in real time without guest accounts, shared tenants, or platform switching. A company on Slack can send messages to a partner company on Microsoft Teams, and each employee sees the conversation natively in their own app. SyncRivo bridges specific designated channels between the two organizations, routing messages bidirectionally with full identity preservation (correct name, avatar, and company badge on both sides), while keeping each company's workspace entirely private and isolated.

How does it work without guest accounts?

Guest accounts work by giving an external user a login to your workspace — they can see your channels, your user directory, and potentially your workspace history. SyncRivo works differently: it creates an API-level routing bridge between two specific channels, one in Company A's workspace and one in Company B's workspace. When someone at Company A sends a message, SyncRivo receives it via API, resolves the sender identity, and delivers it to Company B's designated channel via their platform's API. The message appears as coming from that specific user at Company A, but nobody from Company A was ever granted access to Company B's workspace. It is like a private postal relay between two buildings — messages transit, but neither building gets a key to the other.

Is cross-company messaging secure?

Yes, and SyncRivo's security model is specifically designed to address the four failure modes of alternative approaches. First, tenant isolation: Company A cannot access any of Company B's workspace except the explicitly mapped channels — no user directory, no channel list, no admin settings. Second, zero data-at-rest: messages route through SyncRivo's in-memory pipeline and are never written to disk, creating no third-party message repository. Third, dual-party authorization: both companies' admins must independently authorize the connection — no unilateral bridging is possible. Fourth, audit trails: each company receives their own audit log of cross-company messages for their own compliance review. SyncRivo is SOC 2 Type II certified and provides GDPR-compliant DPAs and HIPAA BAAs for regulated industries.

Can we connect Slack to Teams between different companies?

Yes. This is the most common cross-company messaging use case, and SyncRivo was built specifically to support it. Company A's admin authorizes SyncRivo from their Slack workspace. Company B's admin authorizes SyncRivo from their Microsoft Teams tenant. Both admins independently map their respective channels (for example, Company A's #project-atlas channel in Slack maps to Company B's "Project Atlas" channel in Teams). Messages flow bidirectionally in under 100ms. File sharing, thread replies, emoji reactions, and rich formatting are all preserved across the bridge. Neither company needs to install anything — the integration is purely API-level.

Do both companies need a SyncRivo account?

For enterprise cross-company connections, both companies authorize SyncRivo independently — but only one company needs to hold the primary SyncRivo account and subscription. Company A (the initiator) creates the cross-company connection in SyncRivo and generates a unique invitation link. Company B's admin clicks the link and completes a lightweight authorization flow on their side (authorizing SyncRivo to access only the specific channel they designate). Company B does not need their own SyncRivo subscription to participate in a connection initiated by Company A. For mutual partnerships where both companies want to initiate connections independently, both companies holding accounts provides the most flexible administrative control.

What happens to cross-company messages if one company disconnects?

If either company's admin revokes the SyncRivo authorization or deactivates the cross-company connection, the bridge terminates immediately. No new messages will route across it. Because SyncRivo uses a zero data-at-rest architecture, there is no message history stored on SyncRivo's servers — so there is no residual data to retrieve, delete, or worry about. Messages that were already delivered into each company's native platform before disconnection remain there (in Slack or Teams history), subject to each company's own retention policies. The disconnection is clean: it is as if the messaging relay was simply switched off, with each company retaining only the messages that landed in their own platform.

Is cross-company messaging GDPR compliant?

Yes. SyncRivo's zero data-at-rest architecture is inherently favorable from a GDPR perspective — messages are not stored on SyncRivo servers, so there is no third-party data controller holding EU personal data from either company's users. SyncRivo provides a standard Data Processing Agreement (DPA) that covers cross-company message routing in compliance with GDPR Article 28. For EU-based organizations or organizations with EU employees, SyncRivo's EU data residency option ensures that message routing infrastructure is located within the EU. For specific compliance questions, SyncRivo's compliance team can provide documentation for your DPO review.

How much does cross-company messaging cost?

SyncRivo's pricing for cross-company messaging is based on the number of active cross-company connections and message volume. The Starter tier supports a small number of connections at no cost. The Growth plan ($49/month) supports up to 10 active cross-company connections with unlimited message routing. The Enterprise plan (custom pricing) supports unlimited connections with dedicated infrastructure, SLA guarantees, BAA/DPA agreements, and dedicated support. Compared to guest account costs — which typically run $8–12 per external user per month and require manual provisioning/deprovisioning — SyncRivo delivers dramatically better unit economics for organizations with multiple external partners. A company with 100 guest seats at $10/month ($12,000/year) would typically pay less on SyncRivo's Growth plan while eliminating the security and governance risk entirely.

Cross-Company Messaging Integration: B2B Chat Bridge Guide (2026)

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