HMRC Secure Data Exchange Service (SDES)

Use SDES to securely transfer your documents to and from HM Revenue and Customs (HMRC) for certain services.

If you’ve already registered, you can sign in to your SDES account.

SDES is a free, secure way to transfer files to and from HMRC using your Government Gateway account. It replaces the old Secure Electronic Transfer (SET) service.

It can only be used to transfer specific types of data and isn’t for general use. Before you can use SDES, you must register and confirm that the data you want to transfer is supported by the service.

Register for and set up SDES

To check if your data can be transferred using SDES you must first register by contacting the SDES Support Team.

You’ll need to provide the team with details about your organisation, which they’ll use to check if the data you want to transfer is suitable for SDES.

If it is, you’ll receive an email with a service reference number. For security, you must call the number on the email to get your activation code.

Set up SDES for the first time

Before you start, you’ll need:

  • a Government Gateway account linked to your organisation - if you don’t have one, ask your organisation’s administrator to set you up as a user, or if your organisation doesn’t have one, you must create a new account

  • your service reference number – found in your email

  • an activation code - you can get this by calling the number in your email

Sign in to SDES and enter your security information.

Before using the service, you’ll need to read and accept the terms and conditions on behalf of your organisation. If you don’t have the authority to do this, you should show them to someone that does.

Using SDES

Once you’ve registered for and set up SDES, you can start to use it to transfer your data using either:

  • your web browser
  • automated transfer via FTPS

Web browser

Using SDES in your web browser is the default option. You can use this option to upload and download files, and update your email preferences.

To use SDES in a web browser, you must have Javascript enabled and be using the latest version of:

  • Internet Explorer
  • Google Chrome
  • Firefox
  • Safari
  • Opera

Automated transfer

Before you can use SDES through an automated connection, you need to contact the SDES support team who will help you set this up.

You’ll also need:

  • software capable of transferring files via FTPS using TLS 1.2 protocol
  • a network with access to the internet
  • a static IP address range for whitelisting

Security information

SDES can be used to transfer any file formats up to 10GB in size, apart from executable (.exe) and encrypted files, which will be automatically rejected.

Files are retained in SDES for 6 days (144 hours), after which time they’re deleted for security purposes and can’t be recovered.


All connections to SDES are made using industry standard encryption:

  • HTTPS - for web browser transfers
  • TLS 1.2 protocols - for automated transfers

Files are always encrypted during transit or at rest. There’s no direct access to any files within SDES, meaning that even HMRC technical support teams can’t access files.

Test uploads and downloads

SDES has the option to send and receive a test file known as a ‘proving file’. This is a specifically named file that doesn’t interfere with HMRC systems, but gives you the opportunity to verify upload and download capabilities.

To run the proving file test, you must contact the SDES support team.

Manage users

To use SDES, you need to sign in using your organisation’s Government Gateway account. If someone needs to use SDES but they haven’t got an account linked to your organisation, you’ll need to add them as a new user.

For security reasons, you must not share your own sign in details with other users.

Add a user

To add a user, sign in to the Government Gateway, and follow the steps to add an ‘administrator or ‘assistant’.

If you add the new user as an administrator, they’ll automatically have access to SDES. If you add them as an assistant, you’ll need to assign them to the SET service - this is the old name for SDES and should be used for now.

Remove a user

To remove a user, sign in to the Government Gateway, select either ‘Manage Administrators’ or ‘Manage Assistants’ and delete the relevant user.

Migrating from SET to SDES

If you currently use SET, you’ll be migrated over to SDES by the end of February 2018. HMRC will contact you with details about how and when you can migrate.

Service availability

HMRC services may be slow during busy times. Check if there are any current problems with this service, or times it won’t be available.

Published 24 January 2018