How do I join CTX?

Joining CTX is a simple process:

1) Decide what would like to trade with CTX and make sure that you have the appropriate registry accounts to do so (see Registries below)

2) Complete the online application and CTX Trading Agreement at

3) Send CTX the appropriate documents to confirm you meet our membership criteria

4) The CTX team will process your application

5) Successful applicants receive a countersigned copy of the CTX Trading Agreement and a Welcome Letter containing their CTX access code

What does it cost to join CTX?

Annual membership is currently free*.

New members who do not have a registry account to transfer and retire carbon should note that there will be additional charges for joining and maintaining a registry account. To find out more about these costs you can contact the appropriate person by following the links below (see Registries).

*CTX reserves the right to invoice new users for the costs of administering their application and performing a full credit check, up to a maximum of €500.

Who do I contact to discuss joining CTX?

If you have any questions about the application process you should forward them to

For all other enquiries please use the details provided on our contact page.

What are registries and how do I create a registry account?

Registries provide the transaction and data infrastructure required to trace, transfer and retire carbon credits. They take verified project issuance and create tradable carbon credits, providing a clear chain of ownership that prevents against double-counting.

CTX works with three registry providers – the United Nations, Gold Standard and APX – in order to support trading on its platform.

To purchase United Nations CERs for Voluntary Cancellation you do not require a registry account.

To trade Gold Standard VERs you will require a Gold Standard registry account. Further details, including how to apply, can be found by following this link:

To trade Verified Carbon Standard VERs you will require an APX VCS account and APX EMA account. Further details of each, including how to apply, can be found at: &

How does CTX work?

You can read our rules and trading guide by checking out our resources page.

If you’d like to hear more about the exchange or to see it in action, check out our media centre.