Introduction

Monzo's Open Banking API allows licensed Third Party Providers to access customer's accounts, to provide account information services, or to initiate payments.

If you need support with Monzo's Open Banking API, please create a ticket on the Open Banking Service Desk, or contact [email protected].

Account Information Services API

The Account Information Services API lets authorised Account Information Service Providers access balances, transactions, and more for our customers in the United Kingdom.

Getting Access

To get access to our Open Banking APIs, see the Dynamic Client Registration section below.

Well-Known Endpoints

We've described the paths of our well-known endpoints for the Sandbox and Production environments below.

Endpoints

Base URLs

We've included the Base URLs for our Sandbox and Production environments below.

Base URLs

Dynamic Client Registration

We have implemented the POST /register endpoint in version 3.2 of the Open Banking Dynamic Client Registration specification. You can find the full specification here.

You can find the appropriate URL and supported configuration in our well-known endpoints for each environment.

Authentication

As per the Open Banking specification, we use OAuth 2 and OpenID connect for authentication. We have implemented the redirect flow, with authentication taking place in the customer's Monzo app.

We only support the tls_client_auth authentication method.

Accounts

 {
  "Data": {
    "Account": [
      {
        "AccountId": "acc_0000AAca1egQMHUQX14Mt7",
        "Status": "Enabled",
        "StatusUpdateDateTime": "2021-08-23T15:46:29.775Z",
        "Currency": "GBP",
        "AccountType": "Personal",
        "AccountSubType": "CurrentAccount",
        "Description": "Personal Account",
        "Account": [
          {
            "SchemeName": "UK.OBIE.SortCodeAccountNumber",
            "Identification": "12345699155454",
            "Name": "Camila McSimpburg"
          },
          {
            "SchemeName": "UK.OBIE.IBAN",
            "Identification": "GB25MONZ12345699155454",
            "Name": "Camila McSimpburg"
          }
        ],
        "OpeningDate": "2021-08-23",
        "SwitchStatus": "UK.CASS.NotSwitched"
      }
    ]
  },
  "Links": {
    "Self": "https://openbanking.s101.nonprod-ffs.io/open-banking/v3.1/aisp/accounts"
  },
  "Meta": {}
}

We've implemented version 3.1.10 of the Open Banking accounts specification.

Once you have a consent for a customer, you'll be able to see their:

• Personal (individual) accounts
• Joint accounts
• Business accounts
• Flex account

If the account has been closed, it will still be returned in the response, but with an updated Status.

Note that the fields we return as part of the response depend on whether your consent has the ReadAccountsBasic or ReadAccountsDetail permission. In the former case, we will omit the account scheme data such as account number and sort code or IBAN.

Business Account - Company types

Business account has company type, which is shown in the Description field:

Company type affects payment limits, see Payment Initiation Services API - Domestic Payments Limits for details.

Balances

We've implemented version 3.1.10 of the Open Banking balances specification.

When you query this endpoint, you'll see the customer's InterimAvailable balance. This is the same real-time balance that our customers see in the Monzo app, and it includes pending and settled transactions.

We support an optional query param includePots. When set to true an additional Information balance type will be returned. This balance will be the aggregated account balance made up of the main account balance plus the balance of each pot owned by the account.

Flex

When querying a flex's balance, you'll be returned two balances:

• The InterimAvailable balance: This is the current amount owed on the flex account. Its the amount the customer would need to pay today to pay off their flex.

• The Information balance: This is the current flex balance plus all future interest. Its the balance displayed within the Monzo app.

Transactions

 {
  "Data": {
    "Transaction": [
      {
        "AccountId": "acc_0000AAca1egQMHUQX14Mt7",
        "TransactionId": "tx_0000AGpfr2kVwbONyQ4XFR",
        "CreditDebitIndicator": "Credit",
        "Status": "Booked",
        "BookingDateTime": "2022-02-25T10:35:39.636Z",
        "TransactionInformation": "Mr. Payroll Services",
        "Amount": {
          "Amount": "150.0000",
          "Currency": "GBP"
        },
        "ProprietaryBankTransactionCode": {
          "Code": "bacs",
          "Issuer": "Monzo"
        },
        "DebtorAccount": {
          "SchemeName": "UK.OBIE.SortCodeAccountNumber",
          "Identification": "12345612345678",
          "Name": "Mr Payroll Service"
        },
        "SupplementaryData": {
          "Declined": false,
          "RawTransactionDescription": "MR PAYROLL SERVICE"
        }
      }
    ]
  },
  "Links": {
    "Self": "https://openbanking.s101.nonprod-ffs.io/open-banking/v3.1/aisp/accounts/acc_0000AAca1egQMHUQX14Mt7/transactions?fromBookingDateTime=2022-02-03T00%3A00%3A00"
  },
  "Meta": {}
}

We've implemented version 3.1.10 of the Open Banking transactions specification.

For consistency with our internal systems and the rest of our API, you will need to provide the start and end times in RFC3339 format.

Your consent needs to have either the ReadTransactionsBasic or ReadTransactionsDetail permissions to access this endpoint.

When you query this endpoint, you'll receive all of the transactions that the customer made in the date range specified in the request. Like in the Monzo app, we organise transactions in this response based on creation (presentment) time, not the time the transaction settles.

Transaction amounts can change after the transaction is first created, and you can use the Status field to help identify transactions that are still pending.

You'll only be allowed to fetch transactions that were made in the range defined by TransactionFromDateTime and TransactionToDateTime in your consent. If you try to access transactions outside this range, it won't work.

Rejected transaction status was added in version 3.1.8 of the Open Banking transactions specification. This status will begin to be returned from the AIS API on the 25th of September 2022.

By default, we return transactions oldest to newest - we refer to this as ascending order. To return transactions in reverse, or descending, order an additional query parameter can be provided as part of the /transactions request. Using order=desc will result in the transactions being returned newest to oldest. If you wish to keep transactions ordered oldest to newest then omit the order parameter or set order=asc. All Links will respect the omission or use of the order parameter.

The ProprietaryBankTransactionCode property has two sub-properties: Issuer and Code. Issuer will always be set to Monzo, and the possible values for Code are listed below.

• 3dsecure
• account_interest
• bacs
• card_delivery
• chaps
• collections_settlement
• emergency_cash
• faster_payments
• instalment_loan
• ledger_adjustment
• locked_money
• mastercard
• monzo_business_account_billing
• monzo_flex
• monzo_paid
• overdraft
• p2p_payment
• payport_faster_payments
• rbs_cheque
• sepa
• signup_referral
• spread_the_cost
• topup
• uk_business_pot
• uk_cash_deposits_paypoint
• uk_retail_pot

Parties

We've implemented version 3.1.10. of the Open Banking parties specification

We have implemented the GET /party and GET /accounts/{accountId}/party endpoints for reading details of the consent authoriser and GET /accounts/{accountId}/parties for reading the details of all account holders/owners. These endpoints return the IDs, preferred names, and legal names of account holders/owners.

Your consent needs to have the ReadPartyPSU permission to access the GET /party endpoint and the ReadParty permission to access the GET /account/{accountId}/parties and GET /account/{accountId}/party endpoints.

Pots

Since Pots on Monzo have lots of additional properties that AISPs might find useful, we have implemented a Pots endpoint as an extension to the Open Banking specification.

List Pots

 {
    "Data": {
        "Pot": [
            {
                "PotId": "pot_00009g4AB7nItyHI3R7CVt",
                "AccountId": "acc_00009JrJEKwJrNqKfjwSS",
                "Name": "Savings",
                "Type": "default",
                "CreditDebitIndicator": "Debit",
                "Balance": {
                    "Amount": "5.0000",
                    "Currency": "GBP"
                },
                "Style": "cassette",
                "Goal": {
                    "Amount": "1000.0000",
                    "Currency": "GBP"
                },
                "Created": "2019-02-21T17:13:39.315Z",
                "Updated": "2019-02-21T17:13:39.315Z",
                "Status": "Open"
            },
            {
                "PotId": "pot_00009kIt1QKIXu98cu1RM9",
                "AccountId": "acc_00009JrJEKwJrNqKfjwSS",
                "Name": "Bobs And Bits",
                "Type": "flexible_savings",
                "CreditDebitIndicator": "Debit",
                "Balance": {
                    "Amount": "1000.0000",
                    "Currency": "GBP"
                },
                "Style": "",
                "ImageUrl": "...",
                "Goal": {
                    "Amount": "9999.0000",
                    "Currency": "GBP"
                },
                "Created": "2019-06-28T11:10:29.478Z",
                "Updated": "2019-06-28T11:11:09.173Z",
                "Status": "Open"
            },
            {
                "PotId": "pot_00009kIt8JXWB3R9bYUWkD",
                "AccountId": "acc_00009JrJEKwJrNqKfjwSS",
                "Name": "My Savings Pot",
                "Type": "fixed_savings",
                "CreditDebitIndicator": "Debit",
                "Balance": {
                    "Amount": "1100.0000",
                    "Currency": "GBP"
                },
                "Style": "cassette",
                "LockType": "until_date",
                "LockedUntil": "2020-07-01T00:00:00Z",
                "Created": "2019-06-28T11:11:44.195Z",
                "Updated": "2019-06-28T11:11:44.195Z",
                "Status": "Open"
            }
        ]
    }
}

Endpoints

Note that the fields we return as part of the response depend on whether your consent has the ReadAccountsBasic or ReadAccountsDetailed permission. In the former case, we will omit the Pot name and Image URL from the response.

We'll only return open pots as part of our response. If a customer closes a pot, it won't appear in the response any more.

Field Descriptions

Direct Debits

We've implemented version 3.1.10 of the Open Banking Direct Debits specification.

We have only implemented GET /accounts/{AccountId}/direct-debits endpoint.

Your consent needs to have the ReadDirectDebits permission to access this endpoint.

Scheduled Payments

We've implemented version 3.1.10 of the Open Banking Scheduled Payments specification.

We have only implemented GET /accounts/{AccountId}/scheduled-payments endpoint.

Your consent needs to have either the ReadScheduledPaymentsBasic or ReadScheduledPaymentsDetail permissions to access this endpoint.

Standing Orders

We've implemented version 3.1.10 of the Open Banking Standing Orders specification.

We have only implemented GET /accounts/{AccountId}/standing-orders endpoint.

Your consent needs to have either the ReadStandingOrdersBasic or ReadStandingOrdersDetail permissions to access this endpoint.

Testing in the Sandbox

Our Sandbox environment is a handy playground where you can test your integration before putting it live. We run exactly the same code in our sandbox environment as we do production to make switching between them as easy as possible.

In the sandbox environment, you can automatically have account information consents approved or declined to help with testing. To do this, you should set some specific fields in the Data/SupplementaryData object:

{
  "DesiredStatus": "Authorised",
  "UserID": "user_000xxx"
}

Sandbox Users

Heavy User

UserID: user_0000A4C4ZChWNMEvew2U77 AccountID: acc_0000A4C4ZSskDOixqNPfpR

Medium User

UserID: user_0000A4C4nqORb7K9YYW3r0 AccountID: acc_0000A4C4o66FCYJoERQhHN

Light User

UserID: user_0000A4C4wkPFE7x9at8Ujp AccountID: acc_0000A4C4wz4Ail0f3sONTV

EU (Ireland) User

UserID: user_0000Av3bpksv3AAmdybBCr AccountID: acc_0000Av3bry7sn2XsI3eZ3C

Additional Help

The Open Banking team at Monzo manage the Account Information Services API. If you require additional assistance, email us at [email protected].

Payment Initiation Services API

The Payment Initiation Services API lets authorised Payment Initiation Service Providers make outbound payments from the accounts of our customers in the United Kingdom. All payments initiated through our Payment Initiation Services API are sent through Faster Payments.

Getting Access

To get access to our Open Banking APIs, see the Dynamic Client Registration section below.

Well-Known Endpoints

We've described the paths of our well-known endpoints for the Sandbox and Production environments below.

Base URLs

We've included the Base URLs for our Sandbox and Production environments below.

Base URLs

Dynamic Client Registration

We have implemented the POST /register endpoint in version 3.2 of the Open Banking Dynamic Client Registration specification. You can find the full specification here.

You can find the appropriate URL and supported configuration in our well-known endpoints for each environment.

Authentication

As per the Open Banking specification, we use OAuth 2 and OpenID connect for authentication. We have implemented the redirect flow, with authentication taking place in the customer's Monzo app.

We only support the tls_client_auth authentication method.

Once created, you'll need to turn any consent into a payment order within 24 hours. Once the consent is approved, you'll have one hour.

Domestic Payments

We've implemented version 3.1.10 of the Open Banking Domestic Payments specification.

When you request a consent for Domestic Payments, you should provide UK.OBIE.FPS as the LocalInstrument.

We support account identification using UK.OBIE.SortCodeAccountNumber. We don't support identification using UK.OBIE.IBAN.

You can only make payments in GBP. We don't support other currencies.

Domestic Payments Limits

There are default limits for daily outbound payments:

Scheduled Payments

We've implemented version 3.1.10 of the Open Banking Scheduled Payments specification.

For consistency with our internal systems and the rest of our API, you will need to provide times in RFC3339 format.

When you request a consent for Domestic Payments, you should provide UK.OBIE.FPS as the LocalInstrument.

We support account identification using UK.OBIE.SortCodeAccountNumber. We don't support identification using UK.OBIE.IBAN.

At the moment, we don't support the payment-details endpoint.

You can only make payments in GBP. We don't support other currencies.

Standing Orders

We have implemented version 3.1.10 of the Open Banking Standing Order specification.

For consistency with our internal systems and the rest of our API, you will need to provide times in RFC3339 format.

We support a subset of the standing order frequencies laid out in the specification. These are the same as the frequencies we support in the Monzo app.

We support account identification using UK.OBIE.SortCodeAccountNumber. We don't support identification using UK.OBIE.IBAN.

Since we use the FirstPaymentDate to decide when payments will repeat, we don't use the RecurringPaymentDateTime or RecurringPaymentAmount fields. We'll return an error if you include them.

You can make standing orders with an end date by specifying either a NumberOfPayments or a FinalPaymentDateTime, but we don't let you include both.

At the moment, we don't support the payment-details endpoint.

You can only make payments in GBP. We don't support other currencies.

International Payments

We've implemented version 3.1.11 of the Open Banking International Payments specification.

International Payment Consent

{
  "Data":
  {
    "Initiation":
    {
      "CurrencyOfTransfer": "EUR",
      "DestinationCountryCode": "GB",
      "EndToEndIdentification": "FRESCO.21302.GFX.20",
      "InstructionIdentification": "ACME413",
      "LocalInstrument": "UK.OBIE.SEPACreditTransfer",
      "CreditorAccount":
      {
        "SchemeName": "UK.OBIE.IBAN",
        "Identification": "GB62MONZ12345708578920",
        "Name": "Name Surname"
      },
      "ExchangeRateInformation":
      {
        "RateType": "Indicative",
        "UnitCurrency": "GBP"
      },
      "InstructedAmount":
      {
        "Amount": "100.00",
        "Currency": "GBP"
      },
      "RemittanceInformation":
      {
        "Reference": "FRESCO-101",
        "Unstructured": "Internal ops code 5120101"
      }
    },
    "ReadRefundAccount": "Yes"
  },
  "Risk":
  {
    "PaymentContextCode": "TransferToThirdParty",
    "BeneficiaryAccountType": "Personal"
  }
}

Note that we only support indicative exchange rates (ExchangeRateInformation.RateType must be set to Indicative).

International Payment currencies and rails support

The table below outlines the currencies and supported payment rails, along with the required parameters for the Initiation object (- indicates that the parameter is not required).

CreditorAccount.Name is required for all currencies.

Initiation.DestinationCountryCode is required for all currencies.

If Creditor.PostalAddress is required, the following fields must be provided:

• TownName
• PostCode
• Either AddressLine or BuildingNumber + StreetName

Risk.BeneficiaryAccountType is required and supports the following values: * Personal * JointPersonal * PersonalSavingsAccount * Business * BusinessSavingsAccount

For USD payments, the account type (Checking or Savings) is determined based on Risk.BeneficiaryAccountType.

International Payment Order

The consent's CutOffDateTime is set to 30 minutes after creation. A payment must be initiated within this timeframe (otherwise the payment order will be automatically rejected).

{
  "Data":
  {
    "ConsentId": "obpispinternationalpaymentconsent_0000Ar128pFItDBIlaJ9fd",
    "Initiation":
    {
      "CurrencyOfTransfer": "EUR",
      "DestinationCountryCode": "GB",
      "EndToEndIdentification": "FRESCO.21302.GFX.20",
      "InstructionIdentification": "ACME413",
      "LocalInstrument": "UK.OBIE.SEPACreditTransfer",
      "CreditorAccount":
      {
        "SchemeName": "UK.OBIE.IBAN",
        "Identification": "GB62MONZ12345708578920",
        "Name": "Name Surname"
      },
      "ExchangeRateInformation":
      {
        "RateType": "Indicative",
        "UnitCurrency": "GBP"
      },
      "InstructedAmount":
      {
        "Amount": "100.00",
        "Currency": "GBP"
      },
      "RemittanceInformation":
      {
        "Reference": "FRESCO-101",
        "Unstructured": "Internal ops code 5120101"
      }
    }
  },
  "Risk":
  {
    "PaymentContextCode": "TransferToThirdParty",
    "BeneficiaryAccountType": "Personal"
  }
}

Refund Accounts

{
  "Data": {
    "Initiation": {
      "CreditorAccount": {
        "Identification": "12345612345678",
        "SchemeName": "UK.OBIE.SortCodeAccountNumber"
      },
      "ReadRefundAccount": "Yes"
    }
  }
}

We have enabled reading refund account details as part of domestic and international payment consent resource creation, if requested by the PISP. To read the refund account details set the ReadRefundAccount field to Yes in the consent creation request.

The refund account data will be returned in the payment order creation response. The name on the refund account should pass any confirmation of payee checks.

{
  "Data": {
    "Initiation": {
      "CreditorAccount": {
        "SchemeName": "UK.OBIE.SortCodeAccountNumber",
        "Identification": "12345612345678"
      }
    },
    "ConsentId": "obpispdomesticpaymentconsent_0000AJ93jc7CkiSo8cYCzx",
    "DomesticPaymentId": "obdompayment_0000AJ93nDHX1aE8HE66YT",
    "CreationDateTime": "2022-05-05T14:47:36.545Z",
    "Status": "Pending",
    "StatusUpdateDateTime": "2022-05-05T14:47:36.545Z",
    "ExpectedExecutionDateTime": "2022-05-05T14:47:36.545Z",
    "ExpectedSettlementDateTime": "2022-05-05T14:47:36.545Z",
    "Refund": {
      "Account": {
        "SchemeName": "UK.OBIE.SortCodeAccountNumber",
        "Identification": "12345612345678",
        "Name": "First Last"
      }
    },
    "Debtor": {
      "Name": "First Last",
      "SchemeName": "UK.OBIE.SortCodeAccountNumber",
      "Identification": "12345612345678"
    }
  },
  "Links": {
    "Self": "https://openbanking.s101.nonprod-ffs.io/open-banking/v3.1/pisp/obpispdomesticpaymentconsent_0000AJ93jc7CkiSo8cYCzx"
  },
  "Meta": {}
}

Rejected Payments

When a payment is rejected, we aim to provide TPPs with as much detail as possible. If available, the specific reason for the rejection will be included in the response. TPPs can find the rejection reason within the RejectionReason field in the following locations, depending on the type of payment:

• Single Immediate Payments (SIPs)
  • Data/Initiation/SupplementaryData OBDomestic2
• Variable Recurring Payments (VRPs)
  • Data/Instruction/SupplementaryData OBDomesticVRPInstruction

Other Rejection Scenarios

In some cases, we may not be able to provide specific details about why a payment was rejected. If none of the listed rejection reasons apply, you may encounter the following messages:

Please ask the customer to contact customer support:
For further details on the rejection, the customer will need to get in touch with Monzo's customer support team which they can do via the in-app chat.

Sorry, we're unable to provide additional information on why this payment was rejected:
In certain circumstances, we're unable to share any further information regarding why the payment was rejected.

Testing in the Sandbox

In the sandbox environment, you can automatically have domestic payment requests approved or declined to help with testing. When creating the payment consent, you can add a DesiredStatus field to the Data/Initiation/SupplementaryData object in the consent request. You can set this field to Authorised or Rejected, depending on the behaviour you want.

If you want your payment to come from a specific User and Account then you can also add those values, but you must add both or a random test User and Account is used instead.

We require that the SupplementaryData content is provided in the same order between the consent creation request and the payment request.

{
  "DesiredStatus": "Authorised"
}

{
  "DesiredStatus": "Rejected",
  "UserID": "user_000xxx",
  "AccountID": "account_000yyy"
}

Sandbox Users

Heavy User

UserID: user_0000A4C4ZChWNMEvew2U77 AccountID: acc_0000A4C4ZSskDOixqNPfpR

Medium User

UserID: user_0000A4C4nqORb7K9YYW3r0 AccountID: acc_0000A4C4o66FCYJoERQhHN

Light User

UserID: user_0000A4C4wkPFE7x9at8Ujp AccountID: acc_0000A4C4wz4Ail0f3sONTV

Additional Help

The Open Banking team at Monzo manage the Payment Initiation Services API. If you require additional assistance, email us at [email protected].

Variable Recurring Payments API

The Variable Recurring Payments (VRP) API lets authorised Payment Initiation Service Providers make outbound payments from the accounts of our customers in the United Kingdom. Variable Recurring Payments enable multiple payments to be made under a single long-lived consent without the need for authenticating and approving each payment. Further information on Variable Recurring Payments can be found here.

All payments initiated through our Variable Recurring Payments API are sent through Faster Payments.

We've implemented v3.1.10 of the Open Banking Domestic Variable Recurring Payments specification . All endpoints and models are as outlined in the specifications.

Base URLs

We've included the Base URLs for our Sandbox and Production environments below.

Domestic Variable Recurring Payments

We've implemented version 3.1.10 of the Open Banking Domestic Variable Recurring Payments specification . All endpoints and models are as outlined in the specifications.

We support account identification using UK.OBIE.SortCodeAccountNumber. We don't support identification using UK.OBIE.IBAN.

You can only make payments in GBP. We don't support other currencies.

Omitted Endpoints

We have omitted the implementation of GET /domestic-vrps/{DomesticVRPId}/payment-details.

Variable Recurring Payment Consent Creation

We only support creating consents with a PeriodicAlignment of Consent. Additionally, we currently only allow PeriodType of Day, Week, Month and Year.

Authentication

As per the Open Banking specification, we use OAuth 2 and OpenID connect for authentication. We have implemented the redirect flow, with authentication taking place in the customer's Monzo app.

We only support the tls_client_auth authentication method.

OAuth2 Tokens

We have extended our refresh token expiry for tokens associated with Variable Recurring Payment Consents to account for their long-lived nature. Refresh tokens will have an expiry of 3 years (26,280 hours). Access tokens will continue to expire after 30 hours.

Testing in the Sandbox

In the sandbox environment, you can automatically have Variable Recurring Payment Consent requests approved or declined to help with testing. When creating the consent, you can add a DesiredStatus field to the Data/ControlParameters/SupplementaryData object in the consent request. You can set this field to Authorised or Rejected, depending on the behaviour you want.

{
  "DesiredStatus": "Authorised"
}

Sandbox Users

Heavy User

UserID: user_0000A4C4ZChWNMEvew2U77 AccountID: acc_0000A4C4ZSskDOixqNPfpR

Medium User

UserID: user_0000A4C4nqORb7K9YYW3r0 AccountID: acc_0000A4C4o66FCYJoERQhHN

Light User

UserID: user_0000A4C4wkPFE7x9at8Ujp AccountID: acc_0000A4C4wz4Ail0f3sONTV

Additional Help

The Open Banking team at Monzo manage the Variable Recurring Payment API. If you require additional assistance, email us at [email protected].

Confirmation of Funds API

The Confirmation of Funds API lets authorised Card Based Payment Instrument Issuers check that Monzo customers have enough money for a purchase.

Getting Access

To get access to our Open Banking APIs, see the Dynamic Client Registration section below.

Well-Known Endpoints

We've described the paths of our well-known endpoints for the Sandbox and Production environments below.

Base URLs

We've included the Base URLs for our Sandbox and Production environments below.

Base URLs

Dynamic Client Registration

We have implemented the POST /register endpoint in version 3.2 of the Open Banking Dynamic Client Registration specification. You can find the full specification here.

You can find the appropriate URL and supported configuration in our well-known endpoints for each environment.

Authentication

As per the Open Banking specification, we use OAuth 2 and OpenID connect for authentication. We have implemented the redirect flow, with authentication taking place in the customer's Monzo app.

We only support the tls_client_auth authentication method.

Confirmation of Funds

We have implemented version 3.1.10 of the Open Banking Confirmation of Funds Specification.

We use the redirection flow for approving consents.

You can identify a DebtorAccount using the UK.OBIE.SortCodeAccountNumber scheme. We'll return an error for any other SchemeName.

Additional Help

The Open Banking team at Monzo manage the Confirmation of Funds API. If you require additional assistance, email us at [email protected].

Open Banking Errors

Our Open Banking APIs return errors in line with the Open Banking specification.

OBErrorResponse1

OBError1

A full list of OBErrorResponseError1Code can be found here.

Custom Codes

Due to limitations with OBErrorResponseError1Code we've added two additional codes:

Status Codes

The error prefix of OBErrorResponse1.Code will always be paired with a status code as follows:

Rate Limiting

Monzo's Open Banking API enforces rate limits to maintain platform stability. We apply rate limits both at a platform-wide and TPP level.

TPP Rate Limiting

This limit is shared across all endpoints of our Open Banking APIs and is applied collectively across all client IDs under the same organization ID.

Platform-Wide Rate Limiting

The platform-wide rate limit exists to prevent excessive load on our datastore. This type of rate limiting is not specific to an individual TPP but applies when the datastore is experiencing significantly high load and throttles traffic to reduce it.

If your request is affected by platform-wide rate limiting, it is likely due to temporary high demand on our infrastructure. In this case, retrying the request after a short backoff period should work.

Mapping Errors

Our previous error structure included a code and message. These are now mapped to the new OBErrorResponse1 as follows:

Previous Error Structure

{
  "Code": "bad_request.consent_status",
  "Message": "Consent is not authorised"
}

New Error Structure

{
  "Code": "bad_request.consent_status",
  "Id": "d3628722-749f-4fe9-76f9-f59844ad3714",
  "Message": "Invalid consent status",
  "Errors": [
    {
      "ErrorCode": "UK.OBIE.Resource.InvalidConsentStatus",
      "Message": "Consent is not authorised"
    }
  ]
}

Using Previous Errors

To revert to the previous error behavior, you can include an additional header X-Open-Banking-Legacy-Errors on each request. If this option does not meet your needs, please contact us at [email protected].

Once we are confident that TPPs have successfully migrated to the new error behavior, we will remove the opt-out functionality.

SCA-RTS (PS21/19)

Overview

In November 2021, the FCA set out new rules for standards on Strong Customer Authentication (SCA) in a change to the Regulatory Technical Standards on Strong Customer Authentication and Secure Communication (SCA-RTS).

We (Monzo) will release these changes as of 2022-08-01. This will not be a breaking change.

Consents created before this date will expire after 90-days, as before. Consents created after this date will be long-lived. Please note, this change is only applicable to AIS consents.

TPPs will still be able to provide an ExpirationDateTime on the consent request at which time the consent will expire. If this is not populated, the permissions will be long-lived.

Contact

If you have any queries about these changes then please contact [email protected].

EU PSD2 API

API Specification

Like our UK Open Banking API, our EU PSD2 Dedicated Interface is also built to the Open Banking spec. This means the structure of requests and responses is for the most part the same, with any differences reflecting product differences between UK and EU regions.

Supported Endpoints

Monzo's EU PSD2 API currently only supports Account Information Services (AIS) and Confirmation of Funds API (CBPII). Payment Initiation Services (PIS) will be available at a later date.

Well-Known Endpoints

The Well-Known Endpoints differ from the UK API, and can be seen below:

Endpoints

Base URLs

The Base URLs also differ, with sandbox now on openbanking-s101.eu.monzo.com

Base URLs

Dynamic Client Registration

We have implemented the POST /register endpoint in version 3.2 of the Open Banking Dynamic Client Registration specification. You can find the full specification here.

You can find the appropriate URL and supported configuration in our well known endpoint above.

Differing from DCR requests in the UK, TPPs not registered with the Open Banking directory must use a self-signed (or not signed) SSA. This is where the alg claim is set to none

Example DCR Request

Header

{
  "alg": "PS256",
  "kid": "8ilr3X9lD-oE19ggCRv_ITpSQQc",
  "typ": "JWT"
}

Body

{
  "application_type": "web",
  "aud": "PSDIE-CBI-000000",
  "exp": 1742552600,
  "grant_types": [
    "client_credentials",
    "authorization_code",
    "refresh_token"
  ],
  "iat": 1742549000,
  "id_token_signed_response_alg": "PS256",
  "iss": "278BE778-DCAE-4F7C-9713-89C338F7331C",
  "jti": "279B865B-554E-48E7-89A4-D2705BC607AF",
  "redirect_uris": [
    "https://verify-s101.eu.monzo.com/open-banking/callback"
  ],
  "request_object_signing_alg": "PS256",
  "response_types": [
    "code id_token"
  ],
  "scope": "openid accounts",
  "software_id": "278BE778-DCAE-4F7C-9713-89C338F7331C",
  "software_statement": "eyJhbGciOiJub25lIiwia2lkIjoiIiwidHlwIjoiSldUIn0.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.",
  "tls_client_auth_subject_dn": "C=GB,O=Monzo Bank Limited,organizationIdentifier=PSDIE-CBI-000000,CN=monzo.com",
  "token_endpoint_auth_method": "tls_client_auth"
}

Notes on specific fields:

Header

Body

Header

{
  "alg": "none",
  "typ": "JWT"
}

Example SSA

Body

{
  "iss": "Monzo Bank Ltd",
  "iat": 1742549000,
  "software_environment": "sandbox",
  "software_mode": "Test",
  "software_id": "278BE778-DCAE-4F7C-9713-89C338F7331C",
  "software_client_id": "278BE778-DCAE-4F7C-9713-89C338F7331C",
  "software_client_name": "Monzo",
  "software_client_description": "Manage your money in one place",
  "software_version": "1.0",
  "software_client_uri": "https://developers.monzo.com",
  "software_redirect_uris": [
    "https://verify-s101.eu.monzo.com/open-banking/callback"
  ],
  "software_roles": [
    "AISP"
  ],
  "organisation_competent_authority_claims": {
    "authority_id": "FCAGBR",
    "registration_id": "730427",
    "status": "Active",
    "authorisations": [
      {
        "member_state": "IE",
        "roles": [
          "PISP",
          "AISP",
          "ASPSP"
        ]
      }
    ]
  },
  "software_logo_uri": "https://public-images.monzo.com/logo/avatar_blue.png",
  "org_status": "Active",
  "org_id": "PSDIE-CBI-000000",
  "org_name": "Monzo Bank Limited",
  "org_contacts": [
    {
      "name": "Technical",
      "email": "[email protected]",
      "phone": "07553123807",
      "type": "Technical"
    },
    {
      "name": "Business",
      "email": "[email protected]",
      "phone": "07553123807",
      "type": "Business"
    }
  ],
  "org_jwks_endpoint": "https://api.s101.nonprod-ffs.io/open-banking/eu/jwks.json",
  "software_policy_uri": "https://monzo.com/legal/terms-and-conditions",
  "software_tos_uri": "https://monzo.com/legal/terms-and-conditions",
}

Notes on specific fields:

Header

Body

As per the example in the DCR request above, this should be included in base64 format, ending in . to signify a self signed SSA.

Authentication

As per the Open Banking specification, we use OAuth 2 and OpenID connect for authentication. We have implemented the redirect flow, with authentication taking place in the customer's Monzo app.

We only support the tls_client_auth authentication method.

As per the Well-Known endpoint above, note the authorization_endpoint for the sandbox is https://verify-s101.eu.monzo.com/open-banking/authorize

Certificates

We expect the use of eIDAS QWAC and QSealC certificates issued by a QTSP. We currently have a manually maintained allow-list of trusted QTSPs. If we don't currently trust the QTSP that issues your certificate, then please get in touch at [email protected].

EU Account Information Services API

It works in the same way as described in the Account Information Services API, with some differences outlined below.

EU Accounts

See the Accounts section.

• In the EU, a customer's pots are returned as accounts.

Example of a Current Account and Pot returned:

 {
  "Data": {
    "Account": [
      {
        "AccountId": "acc_0000AvDK9NmomdubVdW9jd",
        "Status": "Enabled",
        "StatusUpdateDateTime": "2025-06-17T07:09:35.3Z",
        "Currency": "EUR",
        "AccountType": "Personal",
        "AccountSubType": "CurrentAccount",
        "Description": "Personal Account",
        "Account":
        [
          {
            "SchemeName": "UK.OBIE.IBAN",
            "Identification": "IE05MONZ00000003102060",
            "Name": "Camila McSimpburg"
          }
        ],
        "OpeningDate": "2025-06-17",
        "SwitchStatus": "UK.CASS.NotSwitched"
      },
      {
        "AccountId": "acc_0000Avmn7n4tTdiAoOXbe5",
        "Status": "Enabled",
        "StatusUpdateDateTime": "2025-07-04T09:49:08.53Z",
        "Currency": "EUR",
        "AccountType": "Personal",
        "AccountSubType": "Savings",
        "Description": "Personal Pot",
        "Account":
        [
          {
            "SchemeName": "",
            "Identification": "",
            "Name": "Holiday"
          }
        ],
        "OpeningDate": "2025-07-04",
    },
    ]
  },
  "Links": {
    "Self": "https://openbanking.s101.nonprod-ffs.io/open-banking/v3.1/aisp/accounts"
  },
  "Meta": {}
}

EU Balances

See Balances section.

• includePots parameter is not supported, as pots are presented as separate accounts in the EU.

EU Pots

EU Confirmation of Funds API

It works in the same way as described in the Confirmation of Funds API, with some differences outlined below.

EU Confirmation of Funds

See Confirmation of Funds section.

• You can identify a DebtorAccount using the UK.OBIE.IBAN scheme. We will return an error for any other SchemeName.
• In the EU, a customer's pots are considered accounts, so you can identify them in the DebtorAccount section.