Svix

Hook0 is an open source Webhooks-as-a-Service platform that helps developers send, receive, manage, and monitor webhooks at scale. It is built for teams that need to add webhook support to their product without spending weeks building retry logic, signatures, monitoring, queues, dead letter handling, event logs, and subscriber management from scratch. With one API call, teams can publish outbound events, while Hook0 handles delivery infrastructure, configurable retry logic, webhook calls, endpoint monitoring, event persistence, and developer tooling. It keeps track of every event an application sends and every webhook call it makes, helping teams debug integrations, inspect delivery attempts, and maintain an audit log. Hook0 supports secure webhook delivery with HMAC signatures, key rotation, TLS encryption, and compliance-focused deployment options. As a fully open source platform, it allows teams to audit the codebase and self-host on their own infrastructure.

EchoRelay is a managed runtime for custom API integrations. Describe one integration once: what comes in, the target system, credentials, the retry policy, and how the answer maps back. EchoRelay validates each inbound request, maps it, replies synchronously, passes streams through, fans out to multiple targets, or queues delivery with automatic retry, a dead-letter queue and replay. Every configuration change is versioned. Preview, diff, dry run, schedule, publish and roll back. When a vendor changes their API or rotates a credential, you update the configuration and publish. Deploy nothing. Build and operate each integration through the REST API, an MCP server so an AI agent can do the wiring, or the web panel. Free to start, no card required.