Is there a way to increase the timeout of an endpoint in module.duct.web?

(note: maybe the issue is not a duct timeout, but somewhere in the code in the handler that calls external api)

I would say that the timeouts are configured in the HTTP server you are using. Unless you configured your Duct project otherwise, jetty is used by default. So it's either a Jetty configuration setting (which may or may not be exposed through duct/server.http.jetty, and may or may not be available in ring/ring-jetty-adapter). Or if you are using a reverse proxy (like nginx, or AWS ElasticLoadBalancer, etc) in front of your HTTP server, you may need to configure the timeout in there.