Custom Gas Tokens empower Appchains to deploy with any ERC-20 token as their native gas token, streamlining fee payments and enhancing token utility. This flexibility allows projects to:
- Boost their token's practical use cases
- Simplify user subsidies through token treasuries
- Enable in-game currencies to cover transaction fees
- Deepen community engagement with their native token
👉 Discover how custom gas tokens revolutionize blockchain ecosystems
Native Gas Tokens vs. Custom Gas Tokens
Default Configuration:
Appchains initially accept ETH deposits from Base as the native gas token.
Custom Configuration:
Appchain operators can specify any Base ERC-20 token during deployment. When deposited:
- The token becomes the Appchain's native gas currency
- All gas fees are paid using this token by default
Technical Requirements for Custom Gas Tokens
Token Specifications
| Requirement Category | Details |
|---|---|
| Network | Must be deployed on Base mainnet or Sepolia |
| Token Standard | Fully compliant ERC-20 |
| Decimals | Exactly 18 decimal places |
| Metadata | Name ≤32 bytes, Symbol ≤32 bytes |
| Token Mechanics | Non-rebasing, no transfer fees, non-yield-bearing |
| Transfer Logic | No callbacks; transfers must not trigger side effects |
Implementation Process
- Deployment
Appchain contracts are initialized with the custom token's Base address. - Deposits
Users lock tokens on Base, triggering minting on the Appchain. - Withdrawals
Burning tokens on Appchain unlocks them on Base. - Fee Payment
All transactions automatically use the custom token for gas.
Key Considerations
Wrapped Gas Token Implementation
The WETH predeploy (0x420...6) serves as the ERC-20 wrapper for your custom gas token. Key features:
deposit()/withdraw()functions convert between native and wrapped forms- Displays as "Wrapped [YourTokenName]" in contracts
Fee Mechanics
Important notes about gas economics:
- Fee calculations still reference ETH-based L1 costs
- Operators receive fees in custom tokens but pay costs in ETH
- No automatic exchange rate mechanisms exist
Migration Limitations
Critical: Chains using ETH as gas cannot transition to custom tokens post-launch due to:
- Complex state migration requirements
- High operational risk
- Potential protocol instability
Frequently Asked Questions
Can I use any ERC-20 token as a gas token?
No—tokens must meet all technical requirements listed above, including 18 decimals and no special transfer logic.
How do users acquire the custom gas token?
Tokens must be obtained through:
- Existing Base liquidity pools
- Project token distributions
- In-game economies (for gaming chains)
What happens if the token price fluctuates dramatically?
Chain operators bear exchange rate risk as:
- Fees are calculated in ETH equivalents
- Collected fees remain in custom tokens
Are there gas savings with custom tokens?
Not inherently—gas costs mirror Base's ETH-based fee market. The primary benefits are token utility and user experience.
👉 Explore real-world implementations of custom gas tokens
For technical specifications, refer to the Custom Gas Token Experimental Specs