I'm not aware of any such feature. You can set up a monthly deposit into your Robinhood account, and you'll get a notification on your phone each time it goes through, but you have to manually submit purchase requests each time as far as I know. At least, that's what I'm doing! I'd love to hear of an alternative. Not that hard to hit the sequence of buttons each month, though.

They have an auto-deposit feature[0], but it doesn't purchase the stocks for you.

There is an unofficial api[1] you could use to cron-buy, though it's unofficial-ness means I don't officially endorse :)

[0] https://support.robinhood.com/hc/en-us/articles/206445496-Tr... [1] https://github.com/sanko/Robinhood

You can use Quantopian to write a Python script that trades on a live Robinhood portfolio. Their target audience is algorithmic traders, but I've written a simple script that just rebalances my portfolio among a small set of index funds each day. Pretty simple to do and completely free.

I'll try to do a blog post when I get the chance.

Robinhood is severely lacking in features and it is mobile app only, no website. If you want that kind of thing with index funds go with another brokerage (Fidelity, Schwab, Vanguard, all have commission free index funds.) The other really crappy thing about Robinhood is that it doesn't integrate with other platforms so if you want to track your wealth with Mint or Personal Capital you can't.