Plain

B2B software companies do support in the Slack Connect channels their customers already sit in, and then lose track of what was promised where. Plain is built for that team. Sanity, Laravel, Stytch and Raycast run their queues on it.

Threads arrive from Slack, Microsoft Teams, email and live chat, and anything the interface can do is available on the same GraphQL API the product itself is built on. Pricing is a base fee plus seats: $35 a month for one seat, or $299 for three, both billed yearly, then $35 and $99 per extra seat. Viewer seats are unlimited and free on every plan. Ari, the customer-facing AI agent, consumes nothing; only Sidekick, the in-thread assistant, draws down a credit allowance.

What Plain does not publish is a price for those credits, or a monthly list rate for any plan. Foundation caps at five seats and 25 Slack channels, Horizon at ten seats, so a growing team hits a sales call rather than a bigger invoice. SSO and SCIM sit on the top tier alone. There is no free plan, no numeric uptime figure, no stated data residency option, and the terms warn you may not recover your data after termination.

Pylon chases the same accounts, and Plain ships a migration path for it alongside one-click importers from Zendesk and Intercom. Front is the closer shared-inbox comparison and has no free observer tier. All of them sit in B2B support software.