Debt Book Turns Personal IOUs Into a Private iPhone Ledger

A loan to a friend is easy to remember until there are several payments, a changed date, or a second person involved. Then the record often ends up split between messages, notes and memory. The difficult part is not lending the money. It is keeping an accurate account of what remains.

Debt Book is an iPhone app for recording money lent or borrowed, payments and interest in a private ledger. It is aimed at personal IOUs, but its separate books also make room for family expenses, customer credit, client advances and small business loans.

From a vague reminder to a ledger

The basic workflow is straightforward. You create a book, add a person and record a transaction. A transaction can represent money lent or borrowed, and can include a simple or compound interest rate with a daily, weekly, monthly or yearly period. When you record a payment, the app recalculates the accrued interest according to those settings.

That matters when a debt is paid in parts. A notebook can hold the original amount and a few handwritten marks, but it leaves the arithmetic and the current balance to the person maintaining it. Debt Book’s purpose is to keep the original transaction, later payments and the resulting total together.

This is not limited to formal loans. The developer positions it for a friend who needs short-term help, a family medical bill, a shopkeeper’s running customer tab, or a freelancer tracking an advance and partial payments. Roommates could use it for rent and bills, while a small business could keep business lending separate from household records.

Separate books prevent mixed records

The app’s main organisational idea is the book. You can keep personal, family and business activity in separate ledgers, with each book holding its own people, transactions and totals. The free plan covers up to two books. A paid upgrade adds unlimited books, along with other features.

This separation is more useful than a single list if your records have different contexts. A customer’s running balance does not need to sit beside a relative’s medical expense, and a business loan should not be mistaken for money owed by a roommate. It also gives each group its own lent and borrowed totals rather than forcing every transaction into one account-like view.

Search is intended to handle the point where the ledger grows beyond what is easy to scan. Debt Book says it can search across people, transactions and books, with date-range filtering. That should help locate a particular payment or older entry without manually opening every record.

Privacy comes with a trade-off

Debt Book is designed as a local-first app. The landing page says records are stored on the iPhone using SwiftData, with no account and no server involved. It also says the app works offline and can be protected with a PIN and auto-lock. An optional iCloud backup is available with the paid upgrade.

That setup suits someone who does not want lending records uploaded to a service or tied to a login. It also means the phone and backup process matter more. If you lose access to the device without a backup or export, a local ledger is harder to recover than an account-based record. The app’s own FAQ says forgotten PINs cannot be recovered. Reinstalling clears the lock, but also clears local data, so recovery depends on an iCloud backup or an exported file.

The privacy model is therefore not simply an advantage. It is an assumption you need to accept. You are responsible for protecting the device and maintaining a backup if the records are important.

Who should use it

Debt Book is a reasonable fit for iPhone users who regularly track informal loans, customer credit or shared expenses and want something more structured than notes or a paper khata. It is especially relevant when partial repayments or interest make a simple reminder insufficient. The local storage, offline operation and optional PIN also suit people who prefer not to create an account for a private financial record.

There are clear boundaries. It runs only on iOS, so it is not a shared cross-platform ledger for households or teams using other devices. The free plan is limited to two books, and features such as unlimited books, cloud backup, PDF statements and data export require the paid upgrade. It also does not remove the social work of agreeing what a payment means or reminding somebody to pay.

For a single iPhone owner who needs a personal debt tracker or IOU tracker, the app’s focused ledger model makes sense. It is a poor fit if you need multi-device collaboration, broad accounting tools or guaranteed recovery without managing your own backup.