How bridging works

Toucan’s first-of-its-kind two-way bridge connects the Puro Connect API to the Toucan registry, deployed on the Celo and Polygon networks. Anyone with a Puro account who has completed the steps in Toucan's Puro Bridge Partner Integration Guide (request access here) can tokenize their CO2 Removal Certificates, or CORCs, and receive them as tokens on-chain.

Once the CORCs are on Toucan's public ledger, you can instantly trade or sell them in the form of TCO2s; retire them to claim the impact of the credit; or bring them back off-chain at any point in time.

These functions give you and your customers maximum flexibility to deploy your assets how and where you want to, which is an important step in Toucan’s mission to provide full traceability and data integrity for carbon markets.


For those interested in a deeper understanding of how this two-way bridge works, we will be updating our diagrams and documentation as we continue to iterate on Version 1 of this bridge.

On a high level, transferring credits onto Toucan via the Carbon Bridge involves a few steps:

  1. Request tokenization and provide details such as the serial numbers of the credits you want to bridge, the project name, and the destination address to Toucan.

  2. Lock credits on the source registry. With the Puro bridge, this is done by immobilizing them in an omnibus account for as long as the tokenized version exists.

  3. Toucan mints a batch NFT with the details you provided, which will "receive" the batch of credits transferred on-chain.

  4. Toucan fractionalizes the batch NFT into TCO2 tokens, one for each credit tokenized, into the blockchain account specified.


In order to transfer credits from Toucan back to the Puro registry, users need to submit a Detokenization request. Consult the Puro Bridge Partner Integration Guide for details on this process. In v1 of the Carbon Bridge, we only support detokenization in the same batch size as tokenization — you can read about v2 here.

All of these steps are required to make sure that the Carbon Bridge maintains integrity (i.e. avoids double issuance or unintended deletion of credits), compliance with KYC / AML regulations, and that integrity + compliance can be verified by anyone.

-> For a more technical look at bridging, read about the different tokens used in the Toucan Protocol on the Toucan carbon tokens page.

If you already have a Puro account, start the bridging process now by requesting access to our Puro Bridge Partner Integration Guide and, once received, initiate Step 1.

Last updated