I wrote a tiny (potentially naff) logger thing that captures all stdout and stderr and logs in realtime to the browser (using server sent events).
Kinda inspired by the way Zeit's now shows you a loading screen during deployment, but I wanted to get at the stdout logging on my now instances (since you don't have this functionality at the moment).
Firslty get the module: npm i -s inline-log, then in your http server (I'm using Express below):
app.use('/_logger', require('inline-log')({ limit: 50 }))That'll capture all the stdout/err and when you visit http://my-site.com/_logger it'll put your logs on the screen (with the last 50 lines). Obviously you can add auth or stuff before the middleware too.