When your app needs to send notifications across email, SMS, and push channels, you'll likely encounter Knock and Courier as top contenders. The choice between them often comes down to whether you prefer batching features or visual design tools, though both platforms share some unexpected limitations that might influence your decision. I'll cover how each platform handles real-world notification scenarios, their key technical differences, and why notification infrastructure requirements are evolving beyond simple message routing in 2025.

TLDR:

• Knock excels at workflow management and batching but requires complex third-party integrations for actual delivery

• Courier offers better template design tools and broader channel support but comes with premium pricing

• Both platforms function as middleware layers that add complexity rather than reducing it

• Velt provides a complete alternative with 25+ collaboration features including advanced notifications in a single integration

• Traditional notification APIs solve only part of the user engagement puzzle, missing modern collaboration requirements

What is Knock and How Does it Work?

Knock is infrastructure for sending product and customer messaging that allows cross-channel product notifications and lifecycle messaging. The platform operates as a notification orchestration system that sits between your application and different downstream providers like email services, SMS gateways, and push notification systems.

When you configure a workflow in Knock, you determine which channels messages should route to, what those messages should look like on each channel, as well as any functions like batch, throttle, or delay you want applied to messages prior to delivery. To send notifications, you trigger your workflows through their API.

Knock targets engineering and product teams who need to send transactional notifications across multiple channels. The platform positions itself as notification infrastructure built to help developers and product teams by providing a set of APIs and components that teams can use to build notification experiences into their applications.

The system requires integration with third-party providers for actual message delivery, acting as a routing layer rather than handling delivery directly. This means you'll still need relationships with SendGrid for email, Twilio for SMS, and other providers for each channel you want to support.

What is Courier and How Does it Work?

Courier provides Engineering and Product teams a platform to ship notifications, allowing them to design and send multi-channel notifications across email, SMS, push, in-app, Slack, and more. The platform follows a "Design Once, Deliver to Many" approach where developers create notification templates once and deliver them across multiple channels through a unified API.

This approach eliminates the need to integrate APIs for each provider separately, though you still need to configure and maintain relationships with downstream services. Courier includes pre-built UI components and a visual design studio for creating notification templates.

Their Inbox component set provides fully customizable components that make it easy to add a notification center to any web or mobile app, with support for iOS, Android, React Native, Flutter, JavaScript, and React.js. The platform targets developers who want to reduce the complexity of building notification systems from scratch while maintaining control over the user experience.

Knock vs Courier Feature Comparison

Both platforms provide multi-channel notification features, but their implementations differ quite a bit. Courier's product is almost identical to Knock and they compete mostly on sales and pricing, though each has distinct limitations that show up during implementation.

Template Management and Design Tools

Courier offers a multi-channel template editor that allows you to design and preview notifications for all channels, while Knock provides only an email-only editor. Courier includes internationalization in all plans, while Knock restricts internationalization to enterprise-only plans.

Courier's visual design studio lets non-technical team members create and modify templates independently. This can be a win for teams where product managers or designers want to iterate on messaging without developer involvement.

Knock provides a more workflow-focused approach with integrated builders for notification workflows. Knock provides an integrated builder for notification workflows where you can see workflows, functions, and notification templates all in one place, which appeals to developers who think in terms of logic flows.

Channel Support and Integrations

Both platforms support email, SMS, push notifications, and in-app messaging. However, there are gaps in specific implementations that might catch you off guard.

Knock cannot create in-app notification feeds via app inbox, nor does it support Slack or Teams, which are important communication mediums for many modern teams. Some necessary workflow nodes like batching and digests are not available in their standard offering.

Courier provides broader integration support with over 50 different notification providers across multiple channels. But here's the thing: more integrations often mean more complexity, not less.

Batching and Workflow Management

Knock is the only notification platform with batching and throttling features, as well as flexible preferences model. This is a key technical differentiator for applications that need to manage notification volume and user preferences granularly.

If you're building an app where users might receive dozens of notifications per day, Knock's batching features can prevent notification fatigue.

Knock's batching and throttling features set it apart from most notification platforms, making it particularly valuable for high-volume applications that need sophisticated message management.

Key Limitations of Both Platforms

Knock's Core Constraints

Knock acts as a router around your third-parties for delivering notifications. For example, you would connect it to your own SendGrid and Twilio, making it more difficult and pricier to set up. This architecture requires maintaining relationships and billing with multiple downstream providers, increasing day-to-day complexity.

Knock lacks account-level limits for controlling the volume of messages sent to a user or a channel, representing a level of granularity and control that is absent in their offering. The platform also provides limited SDK support across programming languages compared to competitors.

You'll find yourself juggling multiple vendor relationships, multiple billing cycles, and multiple points of failure. That sucks when you're trying to simplify your tech stack.

Courier's Implementation Gaps

Courier currently has one of the highest prices in the notification infrastructure category, making it cost-prohibitive for many growing teams. You cannot see step-by-step workflow node logs, including the payload, requests, status, and overall summary at a granular level, which limits debugging options.

The platform also requires integration with third-party providers for actual delivery, similar to Knock, adding extra overhead. When things break (and they will), troubleshooting becomes a multi-vendor nightmare.

Shared Platform Limitations

Courier and Knock share similar flaws due to their similarity. Both platforms function as middleware layers that require extensive third-party integrations, increasing setup complexity and ongoing maintenance requirements.

Neither platform provides complete collaboration features beyond basic notifications. They focus narrowly on message delivery rather than allowing the full range of user engagement features modern applications require.

Users today expect more than just notifications. They want contextual conversations, real-time presence, and rich media interactions. Traditional notification APIs leave these needs unaddressed.

Velt as a Superior Alternative

While Knock and Courier focus on notification routing, Velt provides a complete collaboration layer that includes advanced notification features as part of a full engagement platform. Velt's SDK includes all the commenting and notifications features teams need, letting companies ship collaborative features in just a week without building from scratch.

Velt solves the core limitations of traditional notification APIs by providing 25+ collaboration features including contextual comments, real-time presence, video huddles, screen recording, and intelligent notifications. The platform includes in-product inbox and optional email for re-engagement, plus the ability to attach video recordings when text falls short.

Unlike Knock and Courier's middleware approach, Velt provides both frontend SDK components and backend infrastructure in a single integration. Users can get notifications both in-app and via email, with all comments viewable in one easily accessible place. This eliminates the need to manage multiple third-party provider relationships while providing richer engagement features.

The platform offers enterprise-grade security including self-hosting options, GDPR compliance, SOC 2 Type II certification, and HIPAA compliance with regular penetration testing. Velt's base plan includes 200M comments and 2,000GB of storage, far exceeding the capacity limitations of traditional notification APIs.

More on that below: Velt's approach recognizes that notifications are one piece of a larger collaboration puzzle. When users receive a notification about a comment or update, they want to respond, discuss, and collaborate in context rather than simply acknowledge the message.

Frequently Asked Questions

Which platform is more cost-effective for startups?

Knock typically offers more affordable entry-level pricing, but remember you'll need to factor in costs for third-party providers like SendGrid and Twilio. Courier has higher base pricing but includes more channels in their standard plans. For complete collaboration needs, Velt's platform often provides better value by replacing multiple tools.

Can I migrate from Knock or Courier to another platform later?

Both platforms use proprietary APIs and workflow configurations that make migration challenging. You'll need to rebuild templates, reconfigure workflows, and potentially restructure your notification logic. Planning for future flexibility is important when choosing notification infrastructure.

Do these platforms work with React and other modern frameworks?

Knock provides basic React components but limited support for other frameworks. Courier offers broader framework support including React Native and Flutter. Velt provides first-class support for React, Vue, Svelte, Angular, and other major frameworks with complete SDK options.

How to Choose the Best Notification Solution

When looking at notification infrastructure, consider your broader collaboration and engagement requirements rather than focusing solely on message delivery. Traditional notification APIs like Knock and Courier solve only part of the user engagement puzzle, requiring additional tools for complete user interaction.

Teams should assess whether they need simple message routing or complete collaboration features. Users want chat, presence, voice, and rich media in the same window where they create value. A complete collaboration platform is the fastest step toward that future, letting you roll out features today and grow into advanced features tomorrow.

Consider implementation complexity and long-term scalability. While Knock and Courier require extensive third-party integrations and ongoing provider management, complete platforms like Velt provide everything needed in a single integration.

For teams building modern collaborative applications, choosing a platform that combines notifications with commenting, presence, recording, and other engagement features provides better user experiences and development velocity than assembling separate point solutions.

Think about your users' actual workflows. They want to receive notifications, act on them, discuss them, and collaborate around them. Commenting SDK use cases show how notifications become more valuable when integrated with collaborative features.

The best notification solution is one that fits into a larger engagement strategy, not one that operates in isolation.

Final thoughts on choosing notification platforms for modern apps

You can build complete collaborative experiences with Velt's full platform instead of managing limited notification routing. While Knock and Courier handle basic messaging, modern apps need presence, comments, and real-time features working together. Velt combines all these features in just 10 lines of code. Skip the vendor juggling and ship the interactive experiences users expect.