RCS-Box vs Sinch RCS for Business

RCS-Box is a multi-tenant API for Google RCS Business Messaging, with EU hosting and a German contract partner. It supports text with suggestions, rich cards, carousels, XL messages, and automatic video and image unfurling. Webhooks can deliver incoming messages and opt-in or opt-out events; forwarded webhooks carry an HMAC-SHA256 signature calculated with the tenant API key. Each tenant has a dedicated key and brand-level isolation, plus a configurable country allowlist that defaults to Germany with the +49 prefix. The API manages STOP and START blacklist status per agent. Plans can use standard or newsletter mode, with newsletter billing based on active recipients per month. XL messages are available in all plans from Skizze and count as one conversation. The Free plan costs nothing and includes 100 sessions per calendar month. Skizze costs €49 a month, Atelier €249 a month, and Manufaktur €999 a month. The API is presented for development teams and technology leaders in startups, scale-ups, and enterprise technology units.

Sinch RCS for Business has no write-up on Specifiction yet; its figures are above.