Knock App Alternatives

Single Notification API for Every Channel (SMS, Slack, Whatsapp, Email, SMS, Push, App Inbox)

Open Source freemium $99.0 / Monthly

Your app needs a notification inbox – with real-time sync, web & mobile push, and a UI that matches your brand.

Flagsmith lets you manage feature flags and remote config across web, mobile and server side applications. Deliver true Continuous Integration. Get builds out faster. Control who has access to new features. We're Open Source.

Try for free Open Source freemium

Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.

Open Source free

Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.

Open Source

Courier is a notification API built for developers. Design once, and deliver to any channel – email, Slack, SMS, push, and more – all through a single API.

The ultimate library for managing multi-channel transactional notifications with a single API.

Open Source

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.

Open Source freemium $9.0 / Monthly (Plus usage-based costs. (Growth Plan). )

Engage your mobile and desktop web users with intelligent web push notifications.

Learn when your site is mentioned by other sites for free

Raven is a central platform to orchestrate & track your product's transactional messages across multiple channels like Email, SMS, Push, WhatsApp & more.

Re-engage website visitors with push notifications

Fully managed pub/sub messaging for microservices, distributed systems, and serverless applications

A simple tool for previewing push notification copy