What indie developers should build next

I agree with #1, look for competition. It is astonishing to me how many customer service saas companies seem to pop up every now and then, but many of them seem to succeed, despite there being already hundreds.

I have another rule for indie devs to make money online: Don't build apps for consumers marketplaces (iStore, Play Store). Build/sell apps on marketplaces for businesses eg. Shopify (https://apps.shopify.com/), Salesforce (https://appexchange.salesforce.com/), Weebly (https://www.weebly.com/de/app-center), Github (https://github.com/marketplace), Slack (https://slack.com/apps), Cloudflare (https://www.cloudflare.com/apps)