Pricing: Yes, exactly. It is a flat fee for the whole team. $15/month covers your entire group (up to 20 people). No per-seat billing. We hate that "tax" as much as you do. External Partners: You hit the nail on the head. We are building "Guest Access" so you can invite external partners to specific channels (single-channel guests) easily.Since we don't charge per-seat, adding a few clients/partners won't blow up your bill like it does on Slack. Apps: We are launching as a high-performance PWA (Web) first. It installs to your dock/home screen and feels native, but allows us to iterate faster than maintaining three separate codebases. Native wrappers are coming, but we want the core experience to be rock solid first.

I don't think you can ignore mobile, particularly wrt notifications. I'm not sure if the app stores are as aggressive in restricting wrapped apps as they used to be.