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

# Zero Gas Fee Chain

> SKALE Chain model with zero gas fees using sFUEL, optionally with gasless Proof-of-Work transactions

## Zero Gas Fees

SKALE Chains on Ethereum operate with **zero gas fees** by default. The native gas token (sFUEL) has no monetary value and cannot be traded. It exists purely for EVM compatibility — wallets and tools see a gas token, but users never pay real money for transactions.

**Who pays:** sChain Owner

### Key Points

* **No monetary value** — sFUEL cannot be purchased or sold
* **EVM compatible** — Works with MetaMask, Ethers.js, Foundry, etc.
* **Spam prevention** — Computational requirements still prevent abuse
* **Zero gas fees** — Users don't pay for transactions on SKALE Ethereum chains

### Gasless Transactions (Proof-of-Work)

Zero gas fee chains can optionally enable gasless transactions: users don't even need sFUEL in their wallet. A Proof-of-Work algorithm generates a "magic number" that validates the transaction instead of a gas payment.

#### How It Works

1. Client generates a random 256-bit magic number using PoW
2. The magic number is used as the `gasPrice` in the transaction
3. Validators verify the computational work was performed
4. No sFUEL balance required in the user's wallet

#### When to Use

| Approach      | Requires sFUEL  | Best for                            |
| ------------- | --------------- | ----------------------------------- |
| Zero Gas Fees | Yes (valueless) | Most applications                   |
| Gasless (PoW) | No              | True decentralization, invisible UX |

<Note>
  Proof-of-Work is disabled by default on credit chains.
</Note>

## Gas Chains

A gas chain uses a real token (SKL, ETH, USDC, etc.) as the gas token. This works like a traditional L2 — users pay per-transaction in the chosen token. Gas chains are available on SKALE Expand deployments.

**Who pays:** Users

## Comparison

| Feature         | Zero Gas Fees               | Gasless (PoW) | Gas Chain                |
| --------------- | --------------------------- | ------------- | ------------------------ |
| Who pays        | sChain Owner                | sChain Owner  | Users                    |
| Requires token? | sFUEL (valueless)           | Nothing       | Gas token (market value) |
| EVM compatible? | Yes                         | Yes           | Yes                      |
| Best for        | Most apps on SKALE Ethereum | Consumer UX   | DeFi, financial          |

## Related Topics

* [Credit Chain](/chain-types/credit-chain) — Prepaid credit model for SKALE Base
* [Gas Fees](/developers/integrate-skale/gas-fees) — Full gas fee guide
* [sFUEL Distribution](/developers/run-a-skale-chain/managing-sfuel-distribution)