pusher.com

Realtime messaging service. Free for up to 20 simultaneous connections and 100,000 events/day

Send push notifications to your iOS and Android devices. Effortlessly integrate via API or Webhooks and maintain full control over your alerts. Free plan: 50 messages per day to 1 device and 1 application.

Notifications infrastructure for developers. Send to multiple channels like in-app, email, SMS, Slack, and push with a single API call. The free plan includes 10,000 messages/mo.

Send and receive text messages using your Android phone as an SMS Gateway. Free to send and receive up to 200 messages per month.

Multi-channel notification infrastructure for developers with a prebuilt in-app inbox and no-code template editor. Free plan includes 10,000 messages/mo.

All-in-one Customer Engagement and Automation Tool (email, push, SMS, product tours, banners and more) for SaaS. Free for up to 1,000 active users per month.

Single API for push, in-app, email, chat, SMS, and other messaging channels with template management and other features. The free plan includes 10,000 messages/mo.

RabbitMQ as a Service. Little Lemur plan: max 1 million messages/month, max 20 concurrent connections, max 100 queues, max 10,000 queued messages, multiple nodes in different AZ's