Your team needs to talk. That part is certain. What's less certain—and far more expensive than most companies realize—is whether your chat platform should stand alone or live inside your larger business system. Most teams default to Slack or Microsoft Teams because they're visible and obvious. But the moment you add customer context, contract status, invoice tracking, or WhatsApp messages into the mix, that "obvious" choice starts to cost you real money in data handoffs, duplicate entries, and context loss. This comparison maps four standalone platforms against what Orin's native chat can do—and shows the math at 10, 50, and 100 users where isolation becomes genuinely expensive. The headline numbers: Slack vs. Teams vs. Lark vs. Mattermost Slack charges $7 per user per month on the Pro plan (after a free tier). There are no team size minimums, but most deployments add paid integrations ($5–$20/month each) and inevitably upgrade to Enterprise Grid ($12.50/user/month) when they need compliance features or archiving. A 50-person team at $7/user runs $350/month. At Enterprise Grid, it's $625. Microsoft Teams comes bundled with Microsoft 365 Business Standard ($12.50/user/month) or Business Premium ($20/user/month). If your company already runs Office 365 for email and documents, Teams costs nothing incremental. If not, it's the price of the full suite. For a 50-person team with no existing Microsoft licensing, you're looking at $625–$1,000/month depending on the tier. Lark positions itself as the APAC alternative to Slack. Pricing starts at $5/user/month (lower than Slack's Pro tier in most markets). It has stronger embedded translation, superior offline support, and native integration with Alibaba ecosystem tools—valuable if your supply chain or vendors sit in China or India. For a 50-person team, you're at $250/month, making it the cost winner on chat alone. Mattermost is self-hosted and open-source. There's no per-user fee; you pay for server infrastructure and optional support ($10–$30/month for small deployments). For teams valuing data sovereignty or running heavily regulated workflows, the simplicity is appealing. But "free" vanishes once you add security scanning, high-availability failover, and someone's salary to maintain it. Most SMBs with 50 people end up spending $300–$500/month in hosting and labor. Where the isolation tax kicks in Chat is rarely pure chat. It becomes the place where deals get discussed, customer problems surface, and decisions get made—and none of that context persists anywhere useful. A sales rep closes a deal in Slack. It lands in your CRM as a separate record. A customer messages your support team in WhatsApp. Someone pastes the message into Slack. Someone else manually logs it into a ticket system. A contract gets signed. The news breaks in a chat thread. Your accounting team doesn't see it until an invoice manually lands on their desk. This is the invisible tax. Each handoff—chat to CRM, WhatsApp to ticket, contract to messaging—costs roughly 15–30 minutes per occurrence in a 10-person team, and 2–4 hours in a 50-person team (because context fractures and someone has to reconstruct it). At 50 people, assume your team performs 10–15 of these handoffs daily. That's 20–60 hours per week of rework. At $25/hour average loaded cost, that's $500–$1,500/week, or $2,000–$6,000/month hidden in duplicate work. A standalone chat platform doesn't cause this problem—your architecture does. But it enables it, because chat sits isolated from the systems where deals, contracts, and customer context actually live. Feature comparison: Threading, search, files, and integrations Threading and reply organization: All four standalone platforms (Slack, Teams, Lark, Mattermost) offer threaded replies to keep conversations structured. Orin's native chat includes threading. The edge: negligible. Teams and Slack's threading is most mature, but Lark's is cleaner for APAC teams working asynchronously across time zones. Search and retention: Slack's free tier retains 90 days of messages and shallow search. Pro/Enterprise tiers offer indefinite retention and advanced search operators. Teams offers indefinite retention at all tiers. Lark offers 5 years of searchable history on paid plans. Mattermost lets you set your own retention policy based on server capacity. Orin keeps chat searchable and tied to the contact, deal, or contract record it relates to—a structural advantage for context recovery. File management and storage: Slack charges for file storage overage ($0.25/GB/month above your baseline). Teams bundles storage into Microsoft 365. Lark includes 100 GB per workspace. Mattermost uses your server storage. If your team shares large design files, CADs, or video—common for agencies and product teams—Slack's model degrades fast. A 50-person team sharing weekly design work can hit $100–$300/month in overage costs alone. Integrations: Slack has the largest app marketplace (~2,400 integrations). Teams inte