I'll be honest: I've downloaded and deleted half a dozen co-parenting apps. Most are clunky, overpriced, or feel like they were designed by people who've never actually co-parented.
A friend recommended CoParent Share about three months ago and I reluctantly tried it. Here's what I actually think:
What works well: expense tracking is genuinely frictionless. You log it, your co-parent sees it instantly, it auto-calculates who owes what. No negotiating, no "I don't remember agreeing to that." The receipt storage has saved me twice already when there were questions.
What could be better: the calendar view is functional but not beautiful. Small thing.