OneSignal - Customer engagement platform used by over 1 million developers and marketers; the fastest and most reliable way to send mobile and web push notifications, in-app messages, emails, and SMS.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Gravitec.net - Gravitec.net is a smart web push service that lets you boost subscribers through customizable prompts and automatically target your content to the right audience.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.