multi-channel-messaging
(3)
Knock
Knock is a New York-based notification and customer-engagement infrastructure company that gives developers a single API and dashboard to design, manage, and deliver messages across in-app, email, SMS, push, and chat channels. Founded in 2021 by former Frame.io leaders Sam Seely and Chris Bell, Knock lets product and engineering teams ship cross-channel notification workflows without building and maintaining an in-house system, and now powers messaging for companies like Vercel, Webflow, Amplitude, and Clay.
Telerivet
Telerivet is a cloud communications platform that lets organizations send, automate, and orchestrate messages across SMS, WhatsApp, Voice, USSD, Viber and more - in any market, including the places bigger providers ignore. Born from a Peace Corps insight in Tanzania that most people have a phone but not the internet, it now powers enterprises, governments, NGOs and universities across 150+ countries with a drag-and-drop rules engine, APIs, and a phone-as-gateway model that reaches customers where the network is thin.
Courier
Courier is a San Francisco notification infrastructure platform that lets developers add multi-channel messaging - email, SMS, push, in-app, Slack and more - to their apps through a single API and a drag-and-drop designer. Often described as 'Stripe for notifications,' it routes messages intelligently across channels so engineering teams stop rebuilding notification systems from scratch. Founded in 2019 (YC S19), Courier raised a $35M Series B led by GV in 2022 and powers notifications for companies like New Relic, LaunchDarkly, Lattice, Vanta and Contentful.