Monzo, Starling and Revolut APIs: what an AI assistant can actually read

All three banks support UK Open Banking, so a licensed third party can read balances and transactions from any of them. Only Monzo offers a developer API that a private individual can realistically use for their own current account. Starling's developer access has narrowed over the years and Revolut's own API is for business accounts only. If you want an AI assistant to see your personal accounts across all three, the Open Banking route through a licensed provider is the only one that works for all of them.

Check each bank's developer portal before building anything; scope and terms change without much notice.

There are two ways software can read a UK bank account:

The bank's own API. Built and controlled by the bank. Usually aimed at the account holder or at business customers. Terms, rate limits and scope are whatever the bank decides.

Open Banking. A regulated standard that every large UK bank must support. Access goes through a third party that is registered with the FCA as an Account Information Service Provider (AISP) or acts as an agent of one. The bank has to let a licensed AISP in; it does not get to choose.

For an AI assistant, the distinction matters. A bank API is a private arrangement between you and one bank. Open Banking is a regulated pipe that works across dozens of banks with one consent flow.

Monzo has the most developer-friendly personal API of the three. You authorise through OAuth, approve access in the Monzo app, and can then read accounts, balances, transactions and pots, and post items to the account feed. It is explicitly aimed at personal use: Monzo's terms do not allow it for a product other people sign up to.

For an AI agent this is the easiest bank to prototype with. A self-hosted connector talking to the Monzo API can answer "what did I spend at Tesco this month" in an afternoon. The limits are that it only works for your own Monzo account, tokens need refreshing, and you are relying on a personal-use API that Monzo can change.

Starling built a well-regarded developer platform early on, with personal access tokens that could read and, in some cases, act on accounts. Over time Starling has narrowed what personal customers can do with it and shifted the platform towards business customers and partners. Whether you can still generate a personal token with the scope you need depends on the current state of the developer portal, so check before planning around it.

For AI use, treat Starling as an Open Banking bank. It supports the standard fully and works cleanly through the major providers.

Revolut does not offer a developer API for personal accounts. The Revolut Business API is well documented and covers accounts, transactions, counterparties and payments for business customers. Revolut UK is a regulated bank and supports Open Banking, so personal account data is reachable through a licensed AISP.

Note that Revolut operates several entities across Europe. Which entity holds your account affects which Open Banking route applies (UK Open Banking or EU PSD2), and some providers list them separately.

If you only bank with Monzo and only want your own data, the Monzo API is the quickest path to a working connector.

If you have accounts at two or more of these banks, or want anything that other people could use, you need Open Banking through a licensed provider. That is the same route regardless of bank.

No bank's personal API is suitable for a product. Open Banking is the only route that can be offered to the public, and only with the right regulatory status (see the AISP guide).