FAQ
Quick answers to the things people ask most.
Last updated June 13, 2026
What is Eider?
Eider is a shared expense tracker for the people you split costs with - a partner, a roommate, a household. Add an expense and Eider splits it by your standing rule, then keeps a running tally of who owes whom.
How does splitting work?
Every nest has a split rule - 50/50 by default, or any custom percentage. When you add an expense, Eider applies the rule and updates the balance. You can change the rule any time, and you choose whether the change applies only going forward or to the period's past expenses too.
What happens when I settle up?
Settling closes the current period: the balance resets to zero and that period's expenses are locked as a record. Eider records the settle-up - it doesn't move money, so you pay however you already do (Venmo, cash, a bank transfer).
Can I use Eider on my own?
Yes. A nest works the same with one member as with two - Eider tracks and splits against a placeholder partner until someone joins. Invite them whenever you're ready; nothing you've already added is lost.
Is my data private?
Your expense details are encrypted, and Eider never sells your data. The Privacy policy has the specifics on what we store and why.