Co-founder here - let me respond to some of the concerns voiced here. Firstly, I think if this was titled "what we use to help us do a startup in our spare time

Co-founder here - let me respond to some of the concerns voiced here. Firstly, I think if this was titled "what we use to help us do a startup in our spare time", it would make a little more sense. We are not advocating for any particular approach. This is more a list of things that help us. Doing a startup in your spare time is really, really hard. We could've launched months ago but with limited time we're forced to keep pushing back. There are benefits to this — it keeps you really lean, because you just don't have time for all the little extras. But I'd still rather have more time, especially in big blocks. Our main time is evenings and weekends, which limits us severely. Belle works full-time for Buffer doing content, and they're incredibly supportive of us and Exist. Working for a startup who have been there not so long ago is probably one of the points to mention which make this more sustainable. Belle's time is flexible as she works remotely, meaning she can make time in her day for meetings, emails, etc., and still be able to complete her work for Buffer. And I'm freelancing at the moment, meaning my time is just as flexible (in theory — if you're flat-out, that doesn't mean much). I think edw519's points are good complement in terms of actually building your product and managing your time.