How Bank Connections Work: A Plain-English Guide to Plaid and Read-Only Bank Data

You have almost certainly seen the screen: an app asks to "connect your bank account", a familiar bank login pops up, and moments later the app knows your balance and recent transactions. If that gave you a flicker of unease — good instinct. It is worth understanding exactly what happens in that moment. The short version is reassuring, but only because of how the plumbing is designed.

Much of that plumbing is a company called Plaid. Here is what it is and what it actually does, in plain English.

What Plaid is

Plaid is the connective tissue between your bank and the apps you use. Thousands of financial apps — the well-known payment and budgeting names among them — do not each build a separate, fragile integration with every bank. Instead they use Plaid as a single, secure bridge that speaks to banks on their behalf.

When you connect an account through Plaid, you are authenticating directly with your bank through Plaid's secured flow, and then granting the app permission to receive specific data. Plaid currently connects banks across the United States, Canada, the United Kingdom, and Europe. (South African bank feeds run on different rails — but if you or your clients bank in those regions, Plaid is very likely the bridge involved.)

"Read-only" is the whole point

This is the part that matters most, and the part most people never have explained to them.

The kind of connection apps use for accounting, budgeting, and transaction import is read-only. That means the app can:

• See your account balances and transaction history.

And it explicitly cannot: