Open any folder in longbook

One file, in a folder you choose

Afraid of losing your records the day an app closes? Your longbook is a folder of plain files, and everything in it lives in one file: financial_memory.json. It holds your commitments, every charge past and planned, your accounts, your people and your tags. Beside it sit longbook.schema.json, which describes the format, llms.txt, the guide an AI reads before it writes, and a documents folder for your statements.

The folder can be in your iCloud Drive, where it syncs to your other devices, on this device only, or in any folder you can open from Files on iPhone or Finder on Mac. longbook reads and writes the folder you choose, and nothing else.

Open another folder

Keeping a second longbook, or one a tool made for you? Open it from Settings.

1. Open Settings, then Data & privacy.
2. Choose Open Another Folder….
3. Pick the folder that holds the financial_memory.json, not the file itself.

longbook checks the file first. If it reads, longbook switches to that folder and opens it. Your current folder stays exactly as it is: nothing in it is written, moved or deleted, and you can open it again the same way.

What the format is

Wondering what a tool has to write for longbook to read it? The format is open and documented in two places:

• The schema names every field, which ones are required, and what each one means.
• The guide for AI explains how to write the file well: one row per charge, amounts never converted between currencies, and nothing secret such as a card number.

Three fields are required at the top: app, which is always longbook, version, which is 3, and commitments. Each commitment needs an id, a name, an amount, a currency, a billing_cycle and a status. Charges are optional, and each one names its commitment, its date, its amount and whether it was paid.

This is a complete longbook with one subscription and its next payment planned:

{
  "app": "longbook",
  "version": 3,
  "commitments": [
    {
      "id": "9f6c1b52-3d1e-4a8b-9c47-2f0e6a1d5b83",
      "name": "Netflix",
      "amount": 649,
      "currency": "INR",
      "billing_cycle": "monthly",
      "status": "active"
    }
  ],
  "charges": [
    {
      "commitment_id": "9f6c1b52-3d1e-4a8b-9c47-2f0e6a1d5b83",
      "date": "2026-11-05",
      "amount": 649,
      "paid": false,
      "basis": "plan"
    }
  ]
}

Save it as financial_memory.json in an empty folder, open that folder in longbook, and Netflix shows up with its payment on 5 November.

Any tool or AI can write it

Want a spreadsheet, a script or your own AI to keep your longbook? Point it at the schema and the guide, ask it to write financial_memory.json in that format, and open the folder in longbook. A file made that way opens like one longbook made itself.

When an AI is connected to longbook through its own connector, it reads the guide before every write, and the changes it suggests wait in Proposals for you to keep or undo. Every change your AI makes is reviewed before you keep it.

When a file doesn't match

Concerned that a wrong file could break your longbook? It can't. When the folder you pick has no financial_memory.json, or the file isn't in longbook's format, longbook says so and keeps the folder you were using. Nothing is written to either folder.

The usual reasons a file doesn't read are a missing required field, a version other than 3, a billing_cycle that isn't monthly, yearly, custom or once, or a file that isn't JSON at all. Check the file against the schema, fix what it names, and open the folder again.

If something here is wrong, or you want a step explained further, write to contact@longbook.app.