Unified balance
Estimated time to read: 2 minutes
Unified balance shows the total liquidity in a user's EOA account. It combines the token balance across multiple chains. This lets users spend the available liquidity on any destination chain via chain abstracted transactions.
No bridges or pre-provisioned gas are needed. All cross-chain complexity is handled behind the scenes. Users approve their intent to spend just once for a seamless experience.
Example
Consider a wallet balance:
- Optimism: 0.1 ETH, 0 USDT, 0 USDC
- Arbitrum: 0 ETH, 12 USDT, 0 USDC
- Base: 0 ETH, 10 USDT, 0 USDC
- Scroll: 0 ETH, 0 USDT, 0 USDC
With no unified balance or chain abstraction, user cannot spend any USDT on Scroll unless they use a bridge to convert tokens.
With basic unified balance and chain abstracted transaction, user can spend 18 USDT on Scroll.
| Intent | No Unified Balance / CA | Unified Balance |
|---|---|---|
| Spend 18 USDT on Scroll | ❌ | ✅ |
Cross Chain Swap (XCS)
Balance unification works at two levels, depending upon whether single token type is combined from source chains or can multiple token types be combined from source chains. The capability is subject to whether the chain and tokens supports `permit/EIP-2612':
- Unified Balance (Basic)
- Unified Balance with Cross-Chain Swap (XCS)
The Arcana chain abstraction protocol has evolved to a cross-chain swap enabled unified balance.
Basic Unified Balance
- Users could combine the same token type (for example, USDT) held across multiple source chains into a single, unified balance.
- This allowed spending that token on any destination chain.
- Limitation: Users could only use the unified balance of a single token type. If they lacked enough of that token on all the source chains combined, or had no liquidity on the destination chain, they could not complete the transaction.
Unified Balance with Cross-Chain Swap (XCS)
- The new improved unified balance approach allows cross-chain swaps.
- Users can now spend any supported token (for example, USDT, USDC) from any supported source chain to pay on any destination chain.
- The protocol automatically combines multiple token types and sources to fulfill the transaction, even if the user lacks sufficient balance in a single token or on the destination chain.
- This significantly increases the available liquidity and flexibility, enabling larger transactions and covers gas fee.
- This advanced feature requires chains and tokens to support
permit/EIP-2612. - The chain abstraction protocol falls back to the basic unified balance if the chains
and tokens do not support
permit/EIP-2612.
Example
Consider a wallet balance:
- Optimism: 0.1 ETH, 0 USDT, 0 USDC
- Arbitrum: 0 ETH, 12 USDT, 0 USDC
- Base: 0 ETH, 10 USDT, 0 USDC
- Scroll: 0 ETH, 0 USDT, 0 USDC
With no unified balance or chain abstraction, user cannot spend any USDT on Scroll unless they use a bridge to convert tokens.
With basic unified balance and chain abstracted transaction, user can spend 18 USDT on Scroll.
XCS feature lets user spend 18 USDC on Scroll which is not possible with basic unified balance.
| Intent | No Unified Balance / CA | Unified Balance | Unified Balance + XCS |
|---|---|---|---|
| Spend 18 USDT on Scroll | ❌ | ✅ | ✅ |
| Spend 18 USDC on Scroll | ❌ | ❌ | ✅ |
