Knock

Best Self Hosted Alternatives to Knock

A curated collection of the 4 best self hosted alternatives to Knock.

Knock is a notification infrastructure platform for building, orchestrating, and sending product and transactional messages across email, SMS, push, in-app and Slack. It provides APIs/SDKs, templates, user preference management, routing/flows, and delivery analytics/debugging.

Alternatives List

#1
Svix

Svix

Svix is an open-source webhook service that handles event ingestion, signing, retries, and endpoint management with scalable delivery and client libraries.

Svix screenshot

Svix is an enterprise-ready webhook service for sending events to customer endpoints reliably and securely. It provides a webhook API and delivery infrastructure so you can implement webhooks without building retries, security, and observability from scratch.

Key Features

  • Webhook message ingestion and dispatch with retry handling and deliverability features
  • Webhook signature verification support (symmetric and asymmetric signing schemes)
  • Endpoint and application management for multi-tenant webhook delivery
  • Optional Redis-backed queuing and caching for higher throughput and resiliency
  • PostgreSQL-backed persistence for events and operational data
  • Security-focused controls such as blocking internal IP dispatch by default (SSRF mitigation)
  • OpenTelemetry support for exporting traces to common observability stacks
  • Official client libraries across multiple languages for API usage and webhook verification

Use Cases

  • Add a production-grade webhook system to a SaaS product with minimal custom infrastructure
  • Deliver event notifications to customer systems with robust retries and signing
  • Centralize webhook operations (testing, debugging, and monitoring) across multiple services

Limitations and Considerations

  • Requires PostgreSQL; Redis is optional but recommended for queueing at scale
  • Internal network delivery is restricted by default and requires explicit subnet allowlisting when needed

Svix is a strong fit for teams that need a secure, scalable webhook platform with a clean API and operational tooling. It helps standardize webhook best practices while reducing the effort and risk of building webhook delivery in-house.

3.1kstars
223forks
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#2
Dittofeed

Dittofeed

Developer-focused platform for automated, omnichannel messaging (email, SMS, push, WhatsApp) with low-code journeys, segmentation, templates, and self-hosting.

Dittofeed screenshot

Dittofeed is an open-source customer engagement platform for automating transactional and marketing messages across multiple channels. It provides developer-focused APIs and SDKs plus low-code GUI tools to build journeys, broadcasts, and personalized templates while supporting self-hosted and cloud deployments.

Key Features

  • Omni-channel delivery: email, SMS, mobile push, webhooks and integrations for channels like WhatsApp and Slack
  • Low-code Journey Builder: drag-and-drop automation with branching, local timezone handling, and analytics per branch
  • Powerful Segmentation: multi-condition, AND/OR segment builder that supports event- and trait-based conditions at scale
  • Template editor: Notion-like low-code editor plus HTML/MJML support and Liquid-style personalization
  • Embeddable components & white-labeling: iframe and headless React components for embedding Dittofeed in third-party apps (embedded features in progressive release)
  • Developer-first APIs & SDKs: REST Admin API, Web/Node.js/React Native SDKs, and Git/branch-based workflows for campaign versioning
  • Scalable infrastructure: designed around Postgres and ClickHouse for storage and analytics and deployable via Docker, Helm, or Kubernetes
  • Observability & deployment tooling: Kubernetes/Helm charts, Docker Compose examples, and monitoring integrations for production readiness

Use Cases

  • Lifecycle marketing automation: onboarding flows, re-engagement, and newsletters driven by user events
  • Transactional messaging: password resets, receipts, appointment reminders, and system alerts across channels
  • Embedded messaging for SaaS: expose messaging controls inside a CRM, franchise platform, or agency product via embeddable components

Limitations and Considerations

  • Enterprise embedding, advanced multi-tenancy, and some white-label features are provided under a licensed/closed offering; the public repo and self-hosted distribution do not include those gated enterprise features
  • Integrations with specific provider features (e.g., advanced ESP or carrier functionality) depend on connectors and third-party provider limits; verify required channel provider support before production roll-out

Dittofeed combines low-code UX with developer-grade APIs and scalable storage to support both self-hosted and cloud use. It is suited for teams that need control over data, want to avoid vendor lock-in, and require flexible, embeddable messaging automation.

2.6kstars
314forks
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#3
Hook0

Hook0

Hook0 is an open-source Webhooks-as-a-Service platform to send events via a single API call with subscriptions, retries, persistence, and monitoring.

Hook0 screenshot

Hook0 is an open-source Webhooks-as-a-Service (WaaS) platform that lets your application deliver webhook events to your users through a single API call. It provides a backend service plus a web dashboard to manage subscriptions, delivery, and debugging.

Key Features

  • JSON REST API to publish events and manage webhook resources
  • Fine-grained webhook subscriptions so users can choose which event types to receive
  • Automatic request retries when endpoints are unreachable
  • Event scoping to control which events are delivered to which subscribers
  • Persistence of events and webhook delivery responses for auditing and debugging
  • Modern web dashboard designed for self-serve, non-technical users

Use Cases

  • Add webhook capabilities to a SaaS product without building a full delivery system
  • Replace polling with real-time push updates to external customers or internal services
  • Asynchronous notifications for long-running jobs (e.g., processing pipelines)

Limitations and Considerations

  • Licensed under SSPLv1, which restricts offering Hook0 as a managed service to others

Hook0 is a practical choice for teams that want robust webhook delivery, retries, and observability packaged into a single platform. It helps standardize webhook management while keeping event delivery reliable and debuggable as your product scales.

1.3kstars
77forks
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#4
Notifo

Notifo

Open-source multi-channel notification service with REST API, management UI, templates and channel abstraction for email, web, push and SMS; built with ASP.NET Core and React.

Notifo screenshot

Notifo is an open-source, multi-channel notification service for applications, e-commerce and publishing scenarios. It provides a REST API and a management UI to create templates, manage users and subscriptions, and deliver notifications across channels.

Key Features

  • Rich REST API with OpenAPI-style documentation for creating events, users and subscriptions
  • Management UI for notification templates, users, projects, subscriptions and settings
  • Email template support with MJML and Liquid-style templating
  • Channel abstraction with adapters for Email (Amazon SES), Web (SignalR / sockets), Web Push, Mobile Push (Firebase) and SMS (MessageBird)
  • Reliable delivery with retry mechanisms, queues and schedulers for undelivered or unconfirmed notifications
  • Topic-based subscription model (hierarchical topic paths) and per-topic user preferences
  • Tracking of read/confirmed notifications and delivery reporting
  • Web plugin / overlay to embed notifications into client applications

Use Cases

  • Customer alerts and marketing notifications for e-commerce (price drops, order updates)
  • Real-time notifications for collaboration and task management systems (project/task events)
  • Publishing and news delivery where users subscribe to topics or categories for updates

Limitations and Considerations

  • Project is marked beta: some channels/features (notably mobile push and email integrations) have limited production usage
  • Currently relies on MongoDB as primary datastore; multi-database support is planned but not complete
  • Provider ecosystem is limited out of the box (specific providers implemented; adding new email/SMS providers requires development)
  • Tests and automated API/UI test coverage are limited and further hardening of queues/schedulers is recommended

Notifo is suitable for teams wanting a self-hostable notification platform with topic-based subscriptions and multi-channel delivery. It combines an ASP.NET Core backend and a React/TypeScript frontend and is intended for integration into web and mobile applications.

845stars
82forks
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Why choose an open source alternative?

  • •Data ownership: Keep your data on your own servers
  • •No vendor lock-in: Freedom to switch or modify at any time
  • •Cost savings: Reduce or eliminate subscription fees
  • •Transparency: Audit the code and know exactly what's running