OneSignal vs Courier Comparison: Everything You Need to Know Before Choosing

Courier is a notification infrastructure platform that lets product and engineering teams design notifications once and deliver them to any channel through a single API. Founded in the United States, it addresses a problem that grows with nearly every software product: applications need to send transactional messages by email, SMS, push, in-app inbox, Slack and other channels, and each channel typically requires its own provider integration, templates and delivery logic. Building and maintaining this infrastructure in-house diverts engineering effort from core product work and makes it hard for non-developers to change message content. Courier’s approach is to abstract the underlying providers behind one API and provide a visual designer, routing rules and user preference management, so that developers integrate once while product and marketing teams manage templates and channel strategy without code changes. Key capabilities include a drag-and-drop template designer with brand controls, multi-channel routing with fallback logic, and automations for sequences, delays, digests and batching. An embeddable in-app inbox and toast components let teams add notification centres to web and mobile applications, while a hosted preference centre allows end users to choose how they are contacted. Observability tools provide logs and analytics on delivery, opens and clicks across channels, supporting troubleshooting and optimisation. Courier integrates with a large number of providers, including SendGrid, Amazon SES, Twilio, Firebase Cloud Messaging, Apple Push Notification service, Slack and Microsoft Teams, and connects with data tools such as Segment. SDKs are available for popular programming languages and frameworks. The platform is used by SaaS companies, marketplaces, fintech and consumer applications of varying sizes. By consolidating notification logic in one place, teams can experiment with channels and message content more quickly while maintaining consistent branding and respecting user preferences across products. Pricing starts from around USD 99, typically per month, with a free trial; there is no permanently free version in this listing.