Companies House Integration

Learn how to import key dates and updates for all of your UK clients with a couple of clicks.

Erin Jamison avatar
Written by Erin Jamison
Updated over a week ago

If your practice is located in the United Kingdom, you can integrate your organisation contacts with Companies House. Learn how importing data from Companies House can save time and simplify processes.


Why use Companies House with Karbon?

Syncing Karbon with Companies House makes all of your client’s key statutory information accessible with just a few clicks.

This allows for:

  • Maintaining Karbon as a source of truth by keeping data up to date

  • Pulling in data when onboarding new clients to help decide when to kick-off compliance work

  • Creating Organisations in Karbon by searching for the Company Number or Company Name in Companies House

  • Linking existing Organisation contacts to their corresponding Companies House record

  • Use the Confirmation Statement Due Date or the Accounts Due Date to automatically update the deadline date for your work items

  • Exporting all your client’s data to quickly build reports or mailing lists

  • Instantly identify which client data has changed since the last update

  • Giving team members who aren’t familiar with a client visibility on key dates during handovers

Preparing your Organisations in Karbon to be synced

Ensure that each Organisation has a Company Registration Number saved under the Details > Accounting Details that you would like to sync. This is the link between Companies House and Karbon once the sync is set up and active.

You can update these in bulk using the Bulk Contact Update file.

Connecting Companies House with Karbon

This guide will walk you through the three-step process which takes about five minutes to set up:

  1. Registering with Companies House

  2. Creating an Application to get an API Key

  3. Linking Karbon & Companies House with the API Key

Note: You will need a Company Registration Number saved for all of the contacts that you’d like to sync.

1. Register with Companies House

Registering is how you tell Companies House that you want to access their data with your software, which in this case is Karbon. Once you've registered and told them about your software, you will be provided with an API Key, which can be thought of as a password that your software uses to login to Companies House.

Visit Companies House Developer Hub to register your account.

2. Create your app and API Key

Once registered and logged in, you will need to select Create Application.

You will then be asked to add the details of your application. We recommend calling the application "Karbon" and adding a clear description.

You will also need to select Live as the environment for your application.

You will then see an overview with the Application Details. While on the Application Details screen, select Create new key.

Then add a name for the key, a description and select REST.

Then select Create key, the API Key will be created.

Once saved, you will be taken back to the Application details where you will be able to see the key.

Copy the API key to your clipboard as you will need it for the next step.

3. Linking Karbon & Companies House with the API Key

Now you can add the API key to Karbon and create a secure connection. Start by opening Karbon in a new window and navigate to Connected Apps.

Settings > Connected Apps > Companies House > Manage. Then select Add API Key, which will reveal a pop-up modal.

Paste in the API key and select Update. You should now see a Sync Now button.

Click on it!

Note: You will only have to add your API key initially, as Karbon saves the API key. If you have a lot of data to sync, it may take some time. You can navigate away from the page and the sync will continue in the background.

Once complete, you will see the option to Download in the summary column. After the initial sync, syncing will occur continuously, keeping your synced Organisation data from Companies House up to date and relevant.

Using your integration with Companies House

With the sync active, the details from Companies House are brought into the following contact fields:

  • Legal name

  • Company registration date

  • Financial year-end day and month

  • Company officers

  • Registered office address

  • Dates for last accounts completed

  • Dates for next accounts due

  • Dates for next accounts made up to

  • Dates for next confirmation statement

The Companies House details can then be found in Karbon on the Details tab of an organisation contact, making it easier to find and review information regarding a client.

If you have a missing Company Number that would like to add, you can easily do that under the Details tab:

Create Organisations via the Company Number or Company Name

You can easily add Organisations in Karbon from Companies House by searching for the Company Number or Company Name. This will sync in the Company details automatically from the Companies House record.

Please note: The search can only be performed for Active Companies (i.e. any Dissolved companies aren't included in the search results).

Download .csv export of your client data from Companies House

You are also able to download a .CSV export of your client data from Companies House. The download contains two tabs:

Change Log

This tab highlights all of your clients who had details updated with the following columns:

  • Karbon Key

  • Organisation Name

  • Company Registration Number

  • Update Type

  • Old Value

  • New Value


This tab will contain the data for all of your clients. The export will contain the details listed below:

  • Karbon Key

  • Organisation Name

  • Company Registration Number

  • Accounts next Made Up To

  • Accounts Next Due

  • Accounts. Last Made Uo To

  • Confirmation Statement Next Made Up To

  • Confirmation Statement Next Due

  • Confirmation Statement Last Made Up to

Note: You can access the data for your last 5 imports.

Deadline Dates with Companies House

In Karbon, you have the ability to set Deadline Dates for Work using synced data from Companies House, streamlining your workflow and ensuring timely completion of tasks for your clients.

To utilize this feature, follow these steps:

  1. Creating Work with Companies House Deadlines:

    • Start by creating a new piece of work in Karbon.

    • Ensure that you have selected the appropriate client associated with Companies House.

    • Once you've chosen your client, the associated Deadline will appear as an option in the Deadline drop-down.

    • Here, you'll find the option to choose from Companies House deadlines such as the Confirmation Statement Due Date, the Accounts Due Date, or set a custom date as needed.

    • Proceed to set the deadline and, if required, specify the start date for the work item.

  2. Editing Work with Companies House Deadlines:

    • To edit an existing piece of work and include a Companies House deadline, navigate to the work item you wish to modify.

    • Click on the due date in the work header to access the dropdown menu.

    • From the dropdown, select the appropriate Companies House deadline for your organization.

There's no need to manually update these dates. Karbon automatically detects any changes from Companies House and populates the accurate filing due dates in the deadline field, ensuring your deadlines are always up-to-date and compliant with regulatory requirements.

Who can access the Companies House data?

Only team members with Admin permissions can access the settings to download the data in CSV format.

All team members who have access to the contacts will be able to see the data imported on individual contacts.


If you need help in setting up the integration with Companies House or bulk updating Company Registration Numbers, reach out to our support team and we will assist you.

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