OTS

Communications platform that puts data protection first (alternative to Gitter.im or Slack).

Notification infrastructure for developers.

Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack).

Customer communication platform (alternative to Intercom & Zendesk).

Push notifications to phone or desktop using HTTP PUT/POST, with Android app, CLI and web app, similar to Pushover and Gotify.

Zulip is a powerful, open source group chat application.

Apprise allows you to send a notification to almost all of the most popular notification services available to us today such as: Telegram, Discord, Slack, Amazon SNS, Gotify, etc.

Notification server with Android and CLI clients (alternative to PushBullet).

Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots.

Fully-featured Matrix client for Web, iOS & Android.

Language-agnostic real-time messaging (Websocket or SockJS) server.

Conversational app builder (alternative to Typeform or Landbot).