Introduction

API endpoint

https://api.monzo.com

Examples in this documentation are written using httpie for clarity.

To install httpie on macOS run brew install httpie

The Monzo API is designed to be a predictable and intuitive interface for interacting with users' accounts. We offer both a REST API and webhooks.

The Developers category on our forum is the place to get help with our API, discuss ideas, and show off what you build.

Authentication

The Monzo API implements OAuth 2.0 to allow users to log in to applications without exposing their credentials. The process involves several steps:

1. Acquire an access token, and optionally a refresh token
2. Use the access token to make authenticated requests
3. If you were issued a refresh token: refresh the access token when it expires

Before you begin, you will need to create a client in the developer tools.

Client confidentiality

Clients are designated either confidential or non-confidential.

• Confidential clients keep their client secret hidden. For example, a server-side app that never exposes its secret to users.

• Non-confidential clients cannot keep their client secret hidden. For example, client-side apps that store their client secret on the user's device, where it could be intercepted.

  Non-confidential clients are not issued refresh tokens.

Acquire an access token

Acquiring an access token is a three-step process:

1. Redirect the user to Monzo to authorise your app
2. Monzo redirects the user back to your app with an authorization code
3. Exchange the authorization code for an access token.

This access token doesn't have any permissions until your user has approved access to their data in the Monzo app.

Redirect the user to Monzo

"https://auth.monzo.com/?
    client_id=$client_id&
    redirect_uri=$redirect_uri&
    response_type=code&
    state=$state_token"

Send the user to Monzo in a web browser, where they will log in and grant access to their account.

URL arguments

Monzo redirects back to your app

"https://your.example.com/oauth/callback?
    code=$authorization_code&
    state=$state_token"

If the user allows access to their account, Monzo redirects them back to your app.

URL arguments

Exchange the authorization code

$ http --form POST "https://api.monzo.com/oauth2/token" \
    "grant_type=authorization_code" \
    "client_id=$client_id" \
    "client_secret=$client_secret" \
    "redirect_uri=$redirect_uri" \
    "code=$authorization_code"

{
    "access_token": "access_token",
    "client_id": "client_id",
    "expires_in": 21600,
    "refresh_token": "refresh_token",
    "token_type": "Bearer",
    "user_id": "user_id"
}

When you receive an authorization code, exchange it for an access token. The resulting access token is tied to both your client and an individual Monzo user, and is valid for several hours.

Request arguments

Authenticating requests

$ http "https://api.monzo.com/ping/whoami" \
    "Authorization: Bearer $access_token"

{
    "authenticated": true,
    "client_id": "client_id",
    "user_id": "user_id"
}

All requests must be authenticated with an access token supplied in the Authorization header using the Bearer scheme. Your client may only have one active access token at a time, per user. Acquiring a new access token will invalidate any other token you own for that user.

To get information about an access token, you can call the /ping/whoami endpoint.

Refreshing access

$ http --form POST "https://api.monzo.com/oauth2/token" \
    "grant_type=refresh_token" \
    "client_id=$client_id" \
    "client_secret=$client_secret" \
    "refresh_token=$refresh_token"

{
    "access_token": "access_token_2",
    "client_id": "client_id",
    "expires_in": 21600,
    "refresh_token": "refresh_token_2",
    "token_type": "Bearer",
    "user_id": "user_id"
}

To limit the window of opportunity for attackers in the event an access token is compromised, access tokens expire after a number of hours. To gain long-lived access to a user's account, it's necessary to "refresh" your access when it expires using a refresh token. Only "confidential" clients are issued refresh tokens – "public" clients must ask the user to re-authenticate.

Refreshing an access token will invalidate the previous token, if it is still valid. Refreshing is a one-time operation.

Request arguments

Log Out

$ http --form POST "https://api.monzo.com/oauth2/logout" \
    "Authorization: Bearer $access_token"

While access tokens do expire after a number of hours, you may wish to invalidate the token instantly at a specific time such as when a user chooses to log out of your application.

Once invalidated, the user must go through the authentication process again. You will not be able to refresh the access token.

Pagination

Endpoints which enumerate objects support time-based and cursor-based pagination.

Request arguments

Expanding objects

Some objects contain the id of another object in their response. To save a round-trip, some of these objects can be expanded inline with the expand[] argument, which is repeatable. Objects that can be expanded are noted in individual endpoint documentation.

Accounts

Accounts represent a store of funds, and have a list of transactions.

List accounts

Returns a list of accounts owned by the currently authorised user.

$ http "https://api.monzo.com/accounts" \
    "Authorization: Bearer $access_token"

{
    "accounts": [
        {
            "id": "acc_00009237aqC8c5umZmrRdh",
            "description": "Peter Pan's Account",
            "created": "2015-11-13T12:17:42Z"
        }
    ]
}

To filter by either prepaid or current account, add account_type as a url parameter. Valid account_types are uk_retail, uk_retail_joint.

$ http "https://api.monzo.com/accounts" \
    "Authorization: Bearer $access_token" \
    account_type==uk_retail

Balance

Retrieve information about an account's balance.

Read balance

$ http "https://api.monzo.com/balance" \
    "Authorization: Bearer $access_token" \
    "account_id==$account_id"

{
    "balance": 5000,
    "total_balance": 6000,
    "currency": "GBP",
    "spend_today": 0
}

Returns balance information for a specific account.

Request arguments

Response arguments

Pots

A pot is a place to keep some money separate from the main spending account.

List pots

$ http "https://api.monzo.com/pots" \
    "current_account_id==$account_id" \
    "Authorization: Bearer $access_token"

{
  "pots": [
    {
      "id": "pot_0000778xxfgh4iu8z83nWb",
      "name": "Savings",
      "style": "beach_ball",
      "balance": 133700,
      "currency": "GBP",
      "created": "2017-11-09T12:30:53.695Z",
      "updated": "2017-11-09T12:30:53.695Z",
      "deleted": false
    }
  ]
}

Returns a list of pots owned by the currently authorised user that are associated with the specified account.

Deposit into a pot

$ http --form PUT "https://api.monzo.com/pots/$pot_id/deposit" \
    "Authorization: Bearer $access_token" \
    "source_account_id=$account_id" \
    "amount=$amount" \
    "dedupe_id=$dedupe_id"

Move money from an account owned by the currently authorised user into one of their pots.

{
    "id": "pot_00009exampleP0tOxWb",
    "name": "Wedding Fund",
    "style": "beach_ball",
    "balance": 550100,
    "currency": "GBP",
    "created": "2017-11-09T12:30:53.695Z",
    "updated": "2018-02-26T07:12:04.925Z",
    "deleted": false
}

Request arguments

Response arguments

Withdraw from a pot

$ http --form PUT "https://api.monzo.com/pots/$pot_id/withdraw" \
    "Authorization: Bearer $access_token" \
    "destination_account_id=$account_id" \
    "amount=$amount" \
    "dedupe_id=$dedupe_id"

Move money from a pot owned by the currently authorised user into one of their accounts.

{
    "id": "pot_00009exampleP0tOxWb",
    "name": "Flying Lessons",
    "style": "blue",
    "balance": 350000,
    "currency": "GBP",
    "created": "2017-11-09T12:30:53.695Z",
    "updated": "2018-02-26T07:12:04.925Z",
    "deleted": false
}

Request arguments

Response arguments

Transactions

Transactions are movements of funds into or out of an account. Negative transactions represent debits (ie. spending money) and positive transactions represent credits (ie. receiving money).

Most properties on transactions are self-explanatory. We'll eventually get around to documenting them all, but in the meantime let's discuss the most interesting/confusing ones:

Properties

Retrieve transaction

$ http "https://api.monzo.com/transactions/$transaction_id" \
    "Authorization: Bearer $access_token" \
    # Here we are expanding the merchant \
    "expand[]==merchant"

{
    "transaction": {
        "amount": -510,
        "created": "2015-08-22T12:20:18Z",
        "currency": "GBP",
        "description": "THE DE BEAUVOIR DELI C LONDON        GBR",
        "id": "tx_00008zIcpb1TB4yeIFXMzx",
        "merchant": {
            "address": {
                "address": "98 Southgate Road",
                "city": "London",
                "country": "GB",
                "latitude": 51.54151,
                "longitude": -0.08482400000002599,
                "postcode": "N1 3JD",
                "region": "Greater London"
            },
            "created": "2015-08-22T12:20:18Z",
            "group_id": "grp_00008zIcpbBOaAr7TTP3sv",
            "id": "merch_00008zIcpbAKe8shBxXUtl",
            "logo": "https://pbs.twimg.com/profile_images/527043602623389696/68_SgUWJ.jpeg",
            "emoji": "🍞",
            "name": "The De Beauvoir Deli Co.",
            "category": "eating_out"
        },
        "metadata": {},
        "notes": "Salmon sandwich 🍞",
        "is_load": false,
        "settled": "2015-08-23T12:20:18Z"
    }
}

Returns an individual transaction, fetched by its id.

Request arguments

List transactions

$ http "https://api.monzo.com/transactions" \
    "Authorization: Bearer $access_token" \
    "account_id==$account_id"

{
    "transactions": [
        {
            "amount": -510,
            "created": "2015-08-22T12:20:18Z",
            "currency": "GBP",
            "description": "THE DE BEAUVOIR DELI C LONDON        GBR",
            "id": "tx_00008zIcpb1TB4yeIFXMzx",
            "merchant": "merch_00008zIcpbAKe8shBxXUtl",
            "metadata": {},
            "notes": "Salmon sandwich 🍞",
            "is_load": false,
            "settled": "2015-08-23T12:20:18Z",
            "category": "eating_out"
        },
        {
            "amount": -679,
            "created": "2015-08-23T16:15:03Z",
            "currency": "GBP",
            "description": "VUE BSL LTD            ISLINGTON     GBR",
            "id": "tx_00008zL2INM3xZ41THuRF3",
            "merchant": "merch_00008z6uFVhVBcaZzSQwCX",
            "metadata": {},
            "notes": "",
            "is_load": false,
            "settled": "2015-08-24T16:15:03Z",
            "category": "eating_out"
        },
    ]
}

Returns a list of transactions on the user's account.

Request arguments

Annotate transaction

$ http --form PATCH "https://api.monzo.com/transactions/$transaction_id" \
    "Authorization: Bearer $access_token" \
    "metadata[$key1]=$value1" \
    # Set a key's value as empty to delete it
    "metadata[$key2]="

{
    "transaction": {
        "amount": -679,
        "created": "2015-08-23T16:15:03Z",
        "currency": "GBP",
        "description": "VUE BSL LTD            ISLINGTON     GBR",
        "id": "tx_00008zL2INM3xZ41THuRF3",
        "merchant": "merch_00008z6uFVhVBcaZzSQwCX",
        "metadata": {
            "foo": "bar"
        },
        "notes": "",
        "is_load": false,
        "settled": "2015-08-24T16:15:03Z",
        "category": "eating_out"
    }
}

You may store your own key-value annotations against a transaction in its metadata.

Request arguments

Feed items

The Monzo app is organised around the feed – a reverse-chronological stream of events. Transactions are one such feed item, and your application can create its own feed items to surface relevant information to the user.

It's important to keep a few principals in mind when creating feed items:

1. Feed items are discrete events that happen at a point in time.
2. Because of their prominence within the Monzo app, feed items should contain information of high value.
3. While the appearance of feed items can be customised, care should be taken to match the style of the Monzo app so that your feed items feel part of the experience.

Create feed item

$ http --form POST "https://api.monzo.com/feed" \
    "Authorization: Bearer $access_token" \
    "account_id=$account_id" \
    "type=basic" \
    "url=https://www.example.com/a_page_to_open_on_tap.html" \
    "params[title]=My custom item" \
    "params[image_url]=www.example.com/image.png" \
    "params[background_color]=#FCF1EE" \
    "params[body_color]=#FCF1EE" \
    "params[title_color]=#333333" \
    "params[body]=Some body text to display"

{}

Creates a new feed item on the user's feed. These can be dismissed.

Request arguments (for all feed item types)

Per-type arguments

Each type of feed item supports customisation with a specific list of params. Currently we only support creation of the basic feed item which requires the parameters below. These should be sent as form parameters as in the example to the right.

Basic

The basic type displays an image, with title text and optional body text.
Note the image supports animated gifs!

Request arguments

Attachments

Images (eg. receipts) can be attached to transactions by uploading these via the attachment API. Once an attachment is registered against a transaction, the image will be shown in the transaction detail screen within the Monzo app.

There are two options for attaching images to transactions - either Monzo can host the image, or remote images can be displayed.

If Monzo is hosting the attachment the upload process consists of three steps:

1. Obtain a temporary authorised URL to upload the attachment to.
2. Upload the file to this URL.
3. Register the attachment against a transaction.

If you are hosting the attachment, you can simply register the attachment with the transaction:

1. Register the attachment against a transaction.

Upload attachment

The first step when uploading an attachment is to obtain a temporary URL to which the file can be uploaded. The response will include a file_url which will be the URL of the resulting file, and an upload_url to which the file should be uploaded to.

$ http --form POST "https://api.monzo.com/attachment/upload" \
    "Authorization: Bearer $access_token" \
    "file_name=foo.png" \
    "file_type=image/png" \
    "content_length=12345"

{
    "file_url":"https://s3-eu-west-1.amazonaws.com/mondo-image-uploads/user_00009237hliZellUicKuG1/LcCu4ogv1xW28OCcvOTL-foo.png",
    "upload_url":"https://mondo-image-uploads.s3.amazonaws.com/user_00009237hliZellUicKuG1/LcCu4ogv1xW28OCcvOTL-foo.png?AWSAccessKeyId={EXAMPLE_AWS_ACCESS_KEY_ID}\u0026Expires=1447353431\u0026Signature=k2QeDCCQQHaZeynzYKckejqXRGU%!D(MISSING)"
}

Request arguments

Response arguments

Register attachment

Once you have obtained a URL for an attachment, either by uploading to the upload_url obtained from the upload endpoint above or by hosting a remote image, this URL can then be registered against a transaction. Once an attachment is registered against a transaction this will be displayed on the detail page of a transaction within the Monzo app.

$ http --form POST "https://api.monzo.com/attachment/register" \
    "Authorization: Bearer $access_token" \
    "external_id=tx_00008zIcpb1TB4yeIFXMzx" \
    "file_type=image/png" \
    "file_url=https://s3-eu-west-1.amazonaws.com/mondo-image-uploads/user_00009237hliZellUicKuG1/LcCu4ogv1xW28OCcvOTL-foo.png"

{
    "attachment": {
        "id": "attach_00009238aOAIvVqfb9LrZh",
        "user_id": "user_00009238aMBIIrS5Rdncq9",
        "external_id": "tx_00008zIcpb1TB4yeIFXMzx",
        "file_url": "https://s3-eu-west-1.amazonaws.com/mondo-image-uploads/user_00009237hliZellUicKuG1/LcCu4ogv1xW28OCcvOTL-foo.png",
        "file_type": "image/png",
        "created": "2015-11-12T18:37:02Z"
    }
}

Request arguments

Response arguments

Deregister attachment

To remove an attachment, simply deregister this using its id

$ http --form POST "https://api.monzo.com/attachment/deregister" \
    "Authorization: Bearer $access_token" \
    "id=attach_00009238aOAIvVqfb9LrZh"

{}

Request arguments

Receipts

Receipts are line-item purchase data added to a transaction. They contain all the information about the purchase, including the products you bought, any taxes that were added on, and how you paid. They can also contain extra details about the merchant you spent money at, such as how to contact them, but this may not appear in the app yet.

This is the API currently used by Flux to show receipts at selected retailers in your Monzo app.

Properties

{
    "transaction_id": "tx_00...",
    "external_id": "Order-12345678",
    "total": 1299,
    "currency": "GBP",
    "items": [],
    "taxes": [],
    "payments": [],
    "merchant": {}
}

Receipt Items

[
    {
        "description": "Burger",
        "quantity": 1,
        "unit": "",
        "amount": 539,
        "currency": "GBP",
        "tax": 77,
        "sub_items": [
            {
                "description": "Extra cheese",
                "quantity": 1,
                "unit": "",
                "amount": 100,
                "currency": "GBP",
                "tax": 0
            },
            {
                "description": "Free extra topping promotion",
                "quantity": 1,
                "unit": "",
                "amount": -100,
                "currency": "GBP",
                "tax": 0
            }
        ]
    },
    {
        "description": "Fries",
        "quantity": 1,
        "unit": "",
        "amount": 139,
        "currency": "GBP",
        "tax": 19
    },
    {
        "description": "Milkshake",
        "quantity": 2,
        "unit": "",
        "amount": 198,
        "currency": "GBP",
        "tax": 38
    },
    {
        "description": "Bananas, £1 per kg",
        "quantity": 0.3,
        "unit": "kg",
        "amount": 30,
        "currency": "GBP",
        "tax": 0
    }
]

Items detail each product that was included in the transaction. They let you see more detailed data in your Monzo feed than just how much you spent! 🎉

Items can be made up of sub-items, for example an extra topping on a burger. Sub-items have the same format as items (but they cannot in turn have their own sub-items!). The amounts of the sub-items should add up to amount on the item.

All of the items together, plus the taxes, should add up to the Receipt total.

Properties

Receipt Taxes

[
    {
        "description": "VAT",
        "amount": 10,
        "currency": "GBP",
        "tax_number": "945719291"
    }
]

Taxes will be shown near the bottom of the receipt, just above the total.

Properties

Receipt Payments

[
    {
      "type": "card",
      "bin": "543210",
      "last_four": "0987",
      "auth_code": "123456",
      "aid": "",
      "mid": "",
      "tid": "",
      "amount": 1000,
      "currency": "GBP"
    },
    {
      "type": "cash",
      "amount": 1000,
      "currency": "GBP"
    },
    {
      "type": "gift_card",
      "gift_card_type": "One4all",
      "amount": 1000,
      "currency": "GBP"
    }
]

Payments tell us how you paid for your purchase. While it will always include a card payment, sometimes a cash payment or a gift card is included as well. All of the payments together should add up to the Receipt total.

The payment details might not appear in the app just yet.

Receipt Merchant

The merchant gives us more information about where the purchase was made, to help us decide what to show at the top of the receipt.

Create receipt

$ http PUT "https://api.monzo.com/transaction-receipts" \
    "Authorization: Bearer $access_token" \
    # ... JSON Receipt data ...

{
  "transaction_id": "tx_00...", 
  "external_id": "test-receipt-1",
  "total": 1299,
  "currency": "GBP",
  "items": [
    {
      "description": "Bananas, 70p per kg",
      "quantity": 18.56,
      "unit": "kg",
      "amount": 70,
      "currency": "GBP"
    }
  ]
}

{
    "receipt_id": "receipt_00009NrKwNtI3gKqte",
    ...
}

To attach a receipt to a transaction, make a PUT request to the /transaction-receipts API. Your request should include a body containing the receipt encoded as JSON.

If you’re successful, you’ll get back a 200 OK HTTP response with an empty body. After that, the receipt will show up in your Monzo app!

The external_id is used as an idempotency key, so if you call this endpoint again with the same external ID, it will update the existing receipt.

Retrieve receipt

You can read back a receipt that you've created based on its external ID.

Note that you'll only be able to read your own receipts in this way.

$ http GET "https://api.monzo.com/transaction-receipts" \
    "Authorization: Bearer $access_token" \
    "external_id==test-receipt-1"

{
  "receipt": {
    "id": "receipt_00009eNJqNeJvKeoQA",
    "external_id": "test-receipt-1",
    ...
  }
}

Request arguments

Delete receipt

You can delete a receipt based on its external ID.

Note that you can also update an existing receipt, by creating it again with different values.

$ http DELETE "https://api.monzo.com/transaction-receipts" \
    "Authorization: Bearer $access_token" \
    "external_id==test-receipt-1"

{}

Request arguments

Webhooks

Webhooks allow your application to receive real-time, push notification of events in an account.

Registering a webhook

$ http --form POST "https://api.monzo.com/webhooks" \
    "Authorization: Bearer $access_token" \
    "account_id=$account_id" \
    "url=$url"

{
    "webhook": {
        "account_id": "account_id",
        "id": "webhook_id",
        "url": "http://example.com"
    }
}

Each time a matching event occurs, we will make a POST call to the URL you provide. If the call fails, we will retry up to a maximum of 5 attempts, with exponential backoff.

Request arguments

List webhooks

$ http "https://api.monzo.com/webhooks" \
    "Authorization: Bearer $access_token" \
    "account_id=$account_id"

{
    "webhooks": [
        {
            "account_id": "acc_000091yf79yMwNaZHhHGzp",
            "id": "webhook_000091yhhOmrXQaVZ1Irsv",
            "url": "http://example.com/callback"
        },
        {
            "account_id": "acc_000091yf79yMwNaZHhHGzp",
            "id": "webhook_000091yhhzvJSxLYGAceC9",
            "url": "http://example2.com/anothercallback"
        }
    ]
}

List the webhooks your application has registered on an account.

Request arguments

Deleting a webhook

$ http DELETE "https://api.monzo.com/webhooks/$webhook_id" \
    "Authorization: Bearer $access_token"

{}

When you delete a webhook, we will no longer send notifications to it.

Transaction created

{
    "type": "transaction.created",
    "data": {
        "account_id": "acc_00008gju41AHyfLUzBUk8A",
        "amount": -350,
        "created": "2015-09-04T14:28:40Z",
        "currency": "GBP",
        "description": "Ozone Coffee Roasters",
        "id": "tx_00008zjky19HyFLAzlUk7t",
        "category": "eating_out",
        "is_load": false,
        "settled": "2015-09-05T14:28:40Z",
        "merchant": {
            "address": {
                "address": "98 Southgate Road",
                "city": "London",
                "country": "GB",
                "latitude": 51.54151,
                "longitude": -0.08482400000002599,
                "postcode": "N1 3JD",
                "region": "Greater London"
            },
            "created": "2015-08-22T12:20:18Z",
            "group_id": "grp_00008zIcpbBOaAr7TTP3sv",
            "id": "merch_00008zIcpbAKe8shBxXUtl",
            "logo": "https://pbs.twimg.com/profile_images/527043602623389696/68_SgUWJ.jpeg",
            "emoji": "🍞",
            "name": "The De Beauvoir Deli Co.",
            "category": "eating_out"
        }
    }
}

Each time a new transaction is created in a user's account, we will immediately send information about it in a transaction.created event.

Errors

The Monzo API uses conventional HTTP response codes to indicate errors, and includes more detailed information on the exact nature of an error in the HTTP response.

HTTP response codes

Authentication errors

Errors pertaining to authentication are standard errors but also contain extra information to follow the OAuth specification. Specifically, they contain the error key with the following values:

error argument values

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

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.

Refund Accounts

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

We have enabled reading refund account details as part of domestic 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 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:

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].