OneSignal is a customer engagement platform that empowers businesses to communicate with their customers through various channels like email, SMS, mobile push notifications, web push notifications, and in-app messaging. They offer services to over a million businesses, facilitating the sending of 12 billion messages daily. Their target audience includes businesses of all sizes seeking personalized and automated messaging solutions. OneSignal's unique selling proposition lies in its omnichannel engagement capabilities, superior architecture, and ease of implementation, allowing businesses to tailor messaging to their unique customer journeys efficiently.