// privacy

fin collects nothing.

fin is a command-line tool that runs on your own computer. There is no hosted fin service, no account and no analytics. Its author never sees your data.

what it reads

Balances, transactions, holdings and investment activity for the institutions you connect, from Plaid, using your own Plaid account. It never asks Plaid for account numbers or personal details, and it cannot move money.

Amazon, if you use it

fin amazon is experimental and off until you run fin amazon login. Then it copies your amazon.com cookies from the Chrome profile you pick, after macOS asks you to allow access to Chrome Safe Storage, and reads your Amazon payments and order pages from amazon.com on your computer, as your browser would. Amazon offers no API for this and its Conditions of Use do not allow it; it can stop working at any time. Nothing goes anywhere but amazon.com and your computer.

Costco, if you use it

fin costco is experimental and off until you run fin costco login. It reads your costco.com sign-in from the Chrome profile you select, once at login. If Chrome’s MSAL cache is encrypted, macOS asks you to allow Chrome Safe Storage. fin then renews that sign-in and reads your US warehouse, gas and car wash receipts and your costco.com orders, with their items, directly from Costco on your computer. It uses undocumented website endpoints, may be against Costco’s terms, and can break or be blocked. Requests go only to Costco’s sign-in and orders services.

fin ui, if you use it

fin ui and the --ui flag show your data as pages in your browser, served by fin itself on your computer. The server listens only on 127.0.0.1, so other machines cannot reach it, on a random port with a random token in the address, and it stops when you press Ctrl-C. The pages read the same DuckDB file, read-only, and load nothing from the internet: their fonts (Geist, under the SIL Open Font License) and scripts are built into fin. While it runs, any program on your computer that has the address can read the pages.

updates

Once a day, fin init, fin help and fin version ask github.com which release is latest, as any web request would, and print a line when a newer one exists. It sends nothing about you or your data. fin update downloads that release from GitHub and checks it against its published SHA-256 before installing it. Set FIN_NO_UPDATE_CHECK=1 to turn the check off.

where it goes

Straight from Plaid to your computer. fin prints it to your terminal, or to the AI agent you run it from. That agent and its provider, such as Anthropic or OpenAI, handle it under their own terms. If you run fin sheet, it also writes your transactions and balances to a spreadsheet in your own Google Drive. It signs in with Google's narrowest Drive permission, so it can open only the spreadsheets it created and nothing else in your Drive.

what it stores

Your Plaid keys and access tokens, and the Google sign-in for fin sheet if you use it, in the macOS Keychain, connection names and sync times in ~/.config/fin/state.json, and synced transactions, holdings and balances (one per account for each day you sync) in a DuckDB file in ~/.local/share/fin, all readable only by you. With fin amazon, the Amazon sign-in is kept encrypted in ~/.local/share/fin/amazon with its key in the Keychain, and your payments, orders, order pages and item categories go in the same DuckDB file; fin amazon logout deletes them. With fin costco, the Costco session is encrypted in ~/.local/share/fin/costco with its key in the Keychain. Receipts and orders, their raw JSON and items go in the same DuckDB file. Item categories are stored there too. fin costco logout removes that account’s session, receipts, orders, items and per-item categories. Retailer request logs contain only times, request kinds and HTTP status codes, and are removed at logout. Delete the .duckdb file to forget the history and shared product category defaults.

removing it

Delete the Keychain entries for the service fin, the state file and the data directory (including databases and retailer session files), and nothing fin kept is left on your computer. Your connections live in your own Plaid account; you can review or revoke them at my.plaid.com. Revoke the Google sign-in, if you used fin sheet, at myaccount.google.com/connections.

this website

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questions

Open an issue at github.com/kilianc/fin.