Making HTTP requests from a container that has no curl, using bash /dev/tcp

Tue, 16 Jun 2026 00:00:00 +0000

I needed to check that one container could reach another over an internal Docker network: a plain GET /health against a service on a shared network. The obvious move is curl http://service:8642/health. But this app image was stripped right down, with no curl or wget and nothing else around that I could use to open a socket.

As it turns out, ~~bash can speak HTTP by itself~~ bash can open a TCP socket, and you can write a small HTTP request to it by hand. Opening a connection to a host and port and writing the request needs nothing beyond the shell that’s already there:

Networking · Marek Šuppa

Making HTTP requests from a container that has no curl, using bash /dev/tcp