> ## Documentation Index
> Fetch the complete documentation index at: https://docs.leokit.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Supported Chains

> Complete list of 30+ supported blockchains with metadata and features

## Overview

LeoKit supports cross-chain swaps across 30+ blockchains spanning multiple ecosystems including EVM, UTXO, Cosmos, and other specialized chains.

## EVM Chains

EVM (Ethereum Virtual Machine) compatible chains use the same address format and transaction structure.

| Short Name | Full Name           | Chain ID | Gas Units | Native Asset  |
| ---------- | ------------------- | -------- | --------- | ------------- |
| ETH        | Ethereum Mainnet    | 1        | gwei      | ETH.ETH       |
| ARB        | Arbitrum One        | 42161    | gwei      | ARB.ETH       |
| AVAX       | Avalanche C-Chain   | 43114    | gwei      | AVAX.AVAX     |
| BASE       | Base                | 8453     | gwei      | BASE.ETH      |
| BSC        | Binance Smart Chain | 56       | gwei      | BSC.BNB       |
| POLYGON    | Polygon PoS         | 137      | gwei      | POLYGON.MATIC |
| OPTIMISM   | Optimism            | 10       | gwei      | OPTIMISM.ETH  |
| FANTOM     | Fantom Opera        | 250      | gwei      | FANTOM.FTM    |

### EVM Chain Features

* **Address Format:** 0x-prefixed hexadecimal (42 characters)
* **Token Standard:** ERC-20, BEP-20 (same interface)
* **Gas Model:** Base fee + priority fee (EIP-1559 on most chains)
* **Transaction Type:** Supports both legacy and EIP-1559 transactions
* **Approval Required:** Yes, for token swaps (except native asset swaps)

### EVM-Specific Notes

* **Ethereum (ETH):** Highest security, highest fees, most liquidity
* **Arbitrum (ARB):** Layer 2 rollup, low fees, fast finality
* **Avalanche (AVAX):** High throughput, subsecond finality
* **Base (BASE):** Coinbase Layer 2, growing ecosystem
* **BSC:** High speed, low fees, Binance ecosystem
* **Polygon:** Low fees, high speed, popular for DeFi
* **Optimism:** Layer 2 rollup, optimistic rollup design
* **Fantom:** High speed, DeFi focused

## UTXO Chains

UTXO (Unspent Transaction Output) chains use Bitcoin-like transaction models.

| Short Name | Full Name    | Decimals | Gas Units     | Native Asset | SegWit Support |
| ---------- | ------------ | -------- | ------------- | ------------ | -------------- |
| BTC        | Bitcoin      | 8        | satoshi/vbyte | BTC.BTC      | Yes (native)   |
| LTC        | Litecoin     | 8        | satoshi/vbyte | LTC.LTC      | Yes (native)   |
| DOGE       | Dogecoin     | 8        | shibes/vbyte  | DOGE.DOGE    | No             |
| DASH       | Dash         | 8        | satoshi/vbyte | DASH.DASH    | No             |
| BCH        | Bitcoin Cash | 8        | satoshi/vbyte | BCH.BCH      | No             |
| ZEC        | Zcash        | 8        | satoshi/vbyte | ZEC.ZEC      | No             |

### UTXO Chain Features

* **Transaction Format:** PSBT (Partially Signed Bitcoin Transaction) for most
* **Dust Limit:** Minimum output thresholds to prevent spam
  * BTC/LTC: 546 satoshis
  * DOGE: 100,000,000 shibes (1 DOGE)
* **Memo Support:** OP\_RETURN outputs for cross-chain swaps
* **Change Outputs:** Automatic change calculation and dust handling

### UTXO-Specific Notes

* **Bitcoin (BTC):** Most secure, highest liquidity, SegWit native
* **Litecoin (LTC):** Faster blocks (2.5 min), SegWit support
* **Dogecoin (DOGE):** High transaction volume, meme culture
* **DASH:** InstantSend for fast confirmations, raw tx format (not PSBT)
* **Bitcoin Cash (BCH):** Larger blocks, lower fees
* **Zcash (ZEC):** Privacy features available

### Memo Length Limits

| Chain  | OP\_RETURN Limit | Validation Limit | Notes                 |
| ------ | ---------------- | ---------------- | --------------------- |
| BTC    | 80 bytes         | 150 bytes        | Extended memo support |
| LTC    | 80 bytes         | 150 bytes        | Extended memo support |
| DOGE   | 80 bytes         | 80 bytes         | No extended support   |
| Others | 80 bytes         | Variable         | Chain-specific        |

## Cosmos Chains

Cosmos SDK-based chains use account-based models with IBC (Inter-Blockchain Communication).

| Short Name | Full Name  | Decimals               | Gas Units | Native Asset | Special Notes         |
| ---------- | ---------- | ---------------------- | --------- | ------------ | --------------------- |
| THOR       | THORChain  | 8                      | rune      | THOR.RUNE    | Fixed 0.02 RUNE fee   |
| MAYA       | MAYAChain  | 10 (CACAO), 8 (others) | cacao     | MAYA.CACAO   | 10 decimals for CACAO |
| GAIA       | Cosmos Hub | 6                      | atom      | GAIA.ATOM    | Standard Cosmos chain |
| KUJI       | Kujira     | 6                      | kuji      | KUJI.KUJI    | DeFi-focused chain    |

### Cosmos Chain Features

* **Address Format:** Bech32 encoding with chain-specific prefix
  * THOR: `thor1...`
  * MAYA: `maya1...`
  * GAIA: `cosmos1...`
  * KUJI: `kujira1...`
* **Transaction Type:** Cosmos SDK messages (MsgSend, MsgDeposit, etc.)
* **Gas Model:** Fixed or simulated gas with buffer (typically 1.3x)
* **Memo Support:** Native memo field in transactions

### Cosmos-Specific Notes

* **THORChain (THOR):** Cross-chain liquidity protocol, uses MsgDeposit for native swaps
* **MAYAChain (MAYA):** THORChain fork, **10 decimals for CACAO** (not 8!)
* **Cosmos Hub (GAIA):** Main Cosmos chain, IBC hub
* **Kujira (KUJI):** DeFi platform with native DEX

## Other Chains

Specialized chains with unique architectures.

| Short Name | Full Name     | Decimals | Type          | Native Asset | Special Features        |
| ---------- | ------------- | -------- | ------------- | ------------ | ----------------------- |
| NEAR       | NEAR Protocol | 24       | Account-based | NEAR.NEAR    | YoctoNEAR units (10^24) |
| XRP        | Ripple        | 6        | UTXO-like     | XRP.XRP      | Drops (10^6)            |
| SOL        | Solana        | 9        | Account-based | SOL.SOL      | Lamports (10^9)         |
| TRON       | Tron Network  | 6        | Account-based | TRON.TRX     | Sun units (10^6)        |
| ADA        | Cardano       | 6        | eUTXO         | ADA.ADA      | Extended UTXO model     |

### Chain-Specific Details

#### NEAR Protocol

* **Decimals:** 24 (yoctoNEAR)
* **Contract Format:** name.factory.bridge.near (can contain hyphens)
* **Token Standard:** NEP-141
* **Gas:** Fixed 30 TGas for ft\_transfer
* **Deposit Requirement:** 1 yoctoNEAR for token transfers

#### Ripple (XRP)

* **Decimals:** 6 (drops)
* **Reserve Requirement:** Minimum balance required
* **Destination Tags:** Supported for exchange deposits

#### Solana (SOL)

* **Decimals:** 9 (lamports)
* **Token Standard:** SPL tokens
* **High Performance:** Sub-second finality

#### Tron (TRON)

* **Decimals:** 6 (sun)
* **Token Standard:** TRC-20
* **Energy System:** Alternative to gas fees

#### Cardano (ADA)

* **Decimals:** 6 (lovelace)
* **UTXO Model:** Extended UTXO with smart contracts
* **Native Tokens:** Multi-asset ledger

## Protocol Support Matrix

Different protocols support different blockchain ecosystems.

| Protocol      | EVM              | UTXO                  | Cosmos       | NEAR   | Other Chains |
| ------------- | ---------------- | --------------------- | ------------ | ------ | ------------ |
| THORChain     | ✅ ETH, AVAX, BSC | ✅ BTC, LTC, DOGE, BCH | ✅ THOR, GAIA | ❌      | ✅ XRP, TRON  |
| MAYAChain     | ✅ ETH, ARB       | ✅ BTC, DASH           | ✅ MAYA, THOR | ❌      | ❌            |
| Chainflip     | ✅ ETH, ARB       | ✅ BTC                 | ❌            | ❌      | ❌            |
| Relay         | ✅ All EVM chains | ❌                     | ❌            | ❌      | ❌            |
| NEAR Protocol | ✅ ETH (bridged)  | ✅ BTC (bridged)       | ❌            | ✅ NEAR | ❌            |
| Rango         | ✅ All            | ✅ All                 | ✅ All        | ✅ All  | ✅ All        |

## Chain Selection Guidelines

### For Speed

1. **Fastest Finality:** Solana, Avalanche, Fantom
2. **Fast Confirmation:** NEAR, BSC, Polygon
3. **Standard Speed:** Ethereum, Bitcoin

### For Low Fees

1. **Lowest Fees:** Polygon, BSC, Fantom
2. **Low Fees:** Arbitrum, Base, Optimism
3. **Medium Fees:** Avalanche, NEAR

### For Security

1. **Highest Security:** Bitcoin, Ethereum
2. **High Security:** Litecoin, Cosmos chains
3. **Growing Security:** Layer 2s (Arbitrum, Optimism)

### For Liquidity

1. **Highest Liquidity:** Ethereum, Bitcoin
2. **High Liquidity:** BSC, Polygon, Arbitrum
3. **Growing Liquidity:** Base, NEAR, Avalanche

## Chain-Specific Limitations

### Bitcoin (BTC)

* Memo length limited to 150 bytes for THORChain swaps
* SegWit required for optimal fee calculation

### Dogecoin (DOGE)

* Shorter memo limit (80 bytes) may require THORNames
* Higher dust threshold (1 DOGE)
* Non-SegWit transaction format

### NEAR Protocol

* Limited token support (requires asset equivalents mapping)
* 90-minute quote expiration
* 1 yoctoNEAR deposit required for token transfers

### MAYAChain (MAYA)

* CACAO uses 10 decimals (not 8 like other Cosmos chains)
* Conflicting tolerance parameters not allowed
* Router field required in responses

### EVM Chains

* USDT requires allowance reset to 0 before new approval
* Some tokens may require multiple approval transactions
* Gas estimation may fail, requiring fallback values

## Adding New Chains

To request support for additional chains, please contact [support@leofinance.io](mailto:support@leofinance.io) with:

* Chain name and ticker symbol
* Blockchain type (EVM/UTXO/Cosmos/Other)
* Use case and expected volume
* Community size and ecosystem maturity