Free-tier realtime & messaging

AgentMail

AgentMail is an email inbox API for AI agents. It provides programmatic creation and management of email inboxes, threads, replies, attachments, realtime events, custom domains, semantic search, and data extraction through REST APIs, SDKs, webhooks, and MCP support.

Flock

Flock is a team messaging and collaboration platform with channels, direct messages, voice and video calling, file sharing, to-dos, polls, reminders, and integrated search. It provides desktop apps for Windows, Mac, Linux, and Chrome, plus web access through the Flock service.

Engagespot

Engagespot is a notification infrastructure platform for developers. It provides a single API for sending in-app, email, push, SMS, Slack, Discord, WhatsApp, and webhook notifications, along with templates, workflows, provider management, logging, and a built-in real-time in-app inbox.

Svix

Svix is a webhook infrastructure service for sending, receiving, and testing webhooks through an API and dashboard. It includes webhook dispatch, webhook ingestion, and Svix Play for inspecting and de...

LeanCloud

LeanCloud is a serverless backend platform that provides database storage, server-side logic with LeanEngine, instant messaging, push notifications, SMS, and multiplayer game services. It supports nat...

ScreenSharing

ScreenSharing is a browser-based screen sharing service that lets a user start a session from the web, choose a screen or application window, and share a generated link with viewers. The page describe...

Webpushr

Webpushr is a web push notifications platform that lets websites send browser push messages through a dashboard, REST API, or WordPress plugin. The service supports subscriber targeting by segments an...

SuprSend

SuprSend is a notification infrastructure platform for sending and managing multi-channel notifications across email, SMS, Slack, push, web push, WhatsApp, in-app inbox, and webhooks. It provides work...

Ably is a realtime messaging platform that provides pub/sub APIs, chat, AI transport, live objects, spaces, and live sync for applications that need low-latency updates and state synchronization. The ...

Liveblocks

Liveblocks is a realtime infrastructure platform for multiplayer apps and collaborative AI workflows. It provides hosted primitives for presence, broadcast events, synced storage, feeds, and threads, ...

Pusher

Pusher provides hosted realtime APIs for building features such as live updates, pub/sub messaging, in-app chat, location tracking, and push notifications. Its Channels product supports publish/subscribe messaging across web and mobile clients, while Beams handles programmatic push notifications.

PartyKit is an open source deployment platform for AI agents, multiplayer and local-first apps, games, and websites. It provides a server-side runtime for WebSockets, Fetch request/response handlers, and Wasm, with a CLI for local development and edge deployment.

Amazon SNS

Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service from AWS that helps applications send notifications and distribute events at scale.