Toucan receives fees when liquid carbon reference tokens are redeemed for carbon credits and when off-chain carbon credits are bridged on-chain (revenue).

Toucan is an infrastructure protocol that bundles illiquid carbon credits to liquid carbon reference tokens, and bridges off-chain carbon credits on-chain. Toucan is currently built on Polygon and was founded by Raphaël Haupt in 2020.

Toucan team & investors own and govern the protocol. Toucan’s investors include USV, Earthshot Ventures, etc.

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Toucan Protocol

# Toucan Protocol Total value locked Methodology

## 1. Overview

Toucan Protocol TVL measures the total value of carbon credit tokens locked in the protocol across Polygon and Celo networks. The metric tracks two primary carbon credit tokens: BCT (Base Carbon Tonne) and NCT (Nature Carbon Tonne). TVL is calculated by maintaining running balances of all token deposits, redemptions, and cross-chain transfers, then converting the net token holdings to USD value. This metric answers how much value is currently locked in Toucan's carbon credit infrastructure.

## 2. Data sources

The calculation uses several types of blockchain data and external feeds:
- **Carbon credit deposits**: Parsed `BCT_Deposited_event` and `NCT_Deposited_event` contract events from both Polygon and Celo networks capturing when users deposit carbon credits into the protocol
- **Carbon credit redemptions**: Parsed `BCT_Redeemed_event` and `NCT_Redeemed_event` contract events from both chains capturing when users redeem/withdraw their carbon credits
- **Cross-chain bridge functions**: Polygon function call traces for `BCT_bridgeBurn_function`, `NCT_bridgeBurn_function`, `BCT_bridgeMint_function`, and `NCT_bridgeMint_function` capturing direct bridge operations
- **Cross-chain messaging events**: Polygon parsed contract events for `CrossChainMessenger_BridgeRequestSent_event` and `CrossChainMessenger_BridgeRequestReceived_event` capturing bridge requests between chains
- **Token price feeds**: End-of-day price feeds for BCT and NCT tokens used for USD conversion
- **Token metadata**: Information about token decimals and symbols for proper amount calculations

## 3. Step-by-step calculation

### Component A: Carbon credit deposits
- **Purpose**: Captures when users deposit BCT or NCT tokens into the Toucan protocol
- **Logic**: Extracts deposit events from both Polygon and Celo networks, filtering out removed transactions. Uses hardcoded token addresses for BCT (`0x2f800db0fdb5223b3c3f354886d907a671414a7f`) and NCT (`0xd838290e877e0188a4a44700463419ed96c16107`). Records the actual chain where the deposit occurred while temporarily using Polygon for price conversion due to limited price support for these tokens on Celo
- **Key fields**: `block_timestamp`, `transaction_hash`, `amount` (deposit quantity), `token_address`, and chain information with `real_chain` preserving the actual deposit location

### Component B: Carbon credit redemptions  
- **Purpose**: Captures when users redeem/withdraw their carbon credit tokens from the protocol
- **Logic**: Extracts redemption events from both chains using the same token addresses as deposits. Treats redemption amounts as negative values to represent outflows from the protocol. Applies the same chain handling logic as deposits, preserving actual chain while using Polygon for pricing
- **Key fields**: `block_timestamp`, `transaction_hash`, `amount` (redemption quantity, applied as negative), `token_address`, and chain information

### Component C: Cross-chain bridge burns
- **Purpose**: Tracks tokens being burned on the source chain during cross-chain transfers
- **Logic**: Captures two types of bridge burn events: direct `bridgeBurn` function calls for BCT and NCT tokens, and `CrossChainMessenger_BridgeRequestSent_event` for general bridge requests. For Polygon-to-Celo transfers, records negative amounts on Polygon (tokens leaving) and positive amounts on Celo (tokens arriving). Only includes successful transactions where status is true
- **Key fields**: `block_timestamp`, `transaction_hash`, `amount`, `token_address`, with chain-specific accounting for cross-chain movements

### Component D: Cross-chain bridge mints
- **Purpose**: Tracks tokens being minted on the destination chain during cross-chain transfers
- **Logic**: Captures `bridgeMint` function calls and `CrossChainMessenger_BridgeRequestReceived_event` for Celo-to-Polygon transfers. Records positive amounts on Polygon (tokens arriving) and negative amounts on Celo (tokens leaving). Ensures proper accounting for the reverse direction of bridge burns
- **Key fields**: `block_timestamp`, `transaction_hash`, `amount`, `token_address`, with opposite chain accounting compared to bridge burns

### Component E: Account balance calculation
- **Purpose**: Combines all token movements to calculate running balances by chain and token
- **Logic**: Unions deposits (positive), redemptions (negative), bridge burns (chain-specific positive/negative), and bridge mints (chain-specific positive/negative). Applies decimal correction using token metadata, then aggregates net daily changes by chain and token address. Fills gaps with zeros to ensure continuous time series, then calculates cumulative running balances partitioned by actual chain and token address
- **Key fields**: `timestamp` (daily), `real_chain`, `token_address`, `account_balance` (cumulative net token holdings)

### Final aggregation
- **Combining components**: The running account balances from Component E represent the total tokens held in the protocol at each point in time, serving directly as the TVL in token terms
- **Currency conversion**: Applies USD conversion using end-of-day token price feeds, with decimal correction already applied in the balance calculation step
- **Time aggregation**: Uses daily boundaries with gap filling to ensure complete time series coverage
- **Final calculation**: The TVL equals the USD value of the cumulative account balance for each token on each chain, representing the total value locked in Toucan's carbon credit protocol at any given time

*This methodology was automatically generated by Token Terminal's methodology analyzer.*

Total value locked (TVL)

Total value locked (TVL) — value deposited into the project's applications.

Toucan Protocol

Total value locked

Total value locked

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