webhookd on Ubuntu 24.04 LTS

webhookd is a minimalist, powerful webhook server that turns ordinary shell scripts into HTTP endpoints. Drop an executable script into its scripts directory and it becomes a webhook you can trigger over HTTP, with the script output streamed back to the caller in real time as chunked data or Server Sent Events. It is a lightweight way to wire deploys, automation jobs, notifications and integrations to an incoming HTTP request without standing up a full application. This cloudimg image runs webhookd 1.22.0 on Ubuntu 24.04 LTS.

Security is built in. Running arbitrary shell scripts over HTTP is powerful, so this image makes authentication mandatory: webhookd enforces HTTP Basic authentication against an htpasswd file, and the image ships that file with zero user entries, which is fail closed, so every request to a hook is refused with HTTP 401 until first boot creates a real credential. There is no way to run a hook without a valid username and password.

No webhook password is baked into the image. On first boot the VM generates a unique per VM password, stores it as a bcrypt hash, and writes the plaintext to a root only credentials file, so every VM you deploy gets its own password and there is no default credential to leak. webhookd runs as a dedicated non root service bound to the loopback interface, behind an nginx endpoint that terminates TLS on port 443 with a per VM self signed certificate and preserves streaming output. A shipped self test tool proves an unauthenticated request is refused with HTTP 401 and an authenticated request runs the hook with HTTP 200.

webhookd is distributed under the MIT License, free and open source with no per CPU or per deployment fee. cloudimg is not affiliated with or endorsed by the webhookd project or Nicolas Carlier. cloudimg provides packaging, secure by default hardening, per VM authentication, security patching, and 24/7 support with a guaranteed 24 hour response SLA.