[jraph]

Consulting on the product is another important income, possibly higher than support. It can be:

- developing features or bug fixes in the open source product or an extension that are needed now by the customer

- developing a custom project (not in the open, or actually sometimes in the open) on top of your open source product for the customer

- supporting the customer for some integration with your open source product.

You can also try to sell paid extensions (that are still open source). That would be the case for XWiki Pro apps, or many WordPress extensions.

There's another way to do it, is develop your open source and sell your developer expertise for unrelated customer projects. I've worked somewhere working like this, but don't really believe it works well because you are not actually spending time in your project when you are doing this, and you are not incentivized to develop your own product when you do this. You are basically a consulting company. But you can still decide to do a bit of this.

Consulting and support can work for solo developers, but that might push quite some pressure and make it difficult to disconnect depending on the way you do this.