# FAQs

## General

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<summary><mark style="color:purple;">How does Facet differ from traditional Layer 2 solutions?</mark></summary>

Facet operates as an unstoppable rollup, fundamentally different from traditional L2s in two key ways:

1. **No centralized sequencer**: Traditional L2s use centralized sequencers that can censor transactions or be shut down. Facet transactions go directly to Ethereum's `0xface7` address, where they're sequenced by Ethereum validators - making censorship impossible.
2. **No privileged bridge**: Traditional L2s depend on upgradeable bridge contracts controlled by small multisigs. Facet has no canonical bridge and uses a native gas token (FCT), eliminating this critical vulnerability.

These features make Facet truly unstoppable - it runs as long as Ethereum runs, with no admin keys that can halt the system.

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<summary><mark style="color:purple;">Why does Facet use ZK Fault Proofs instead of full ZK proofs?</mark></summary>

Facet uses ZK Fault Proofs because they provide the best of both worlds:

**Efficiency in the common case:** When there are no disputes (the normal situation), no proofs need to be generated or verified. This makes the system free to operate in the happy path, unlike full ZK rollups that must prove every state transition.

**Fast dispute resolution:** When a dispute does occur, it's resolved in a single transaction using a ZK proof. This avoids the complex multi-round games and escalating bonds of traditional interactive fault proofs.

**No admin overrides:** The entire system is immutable with no pause functions or guardian overrides, ensuring true unstoppability.

This approach aligns with Facet's philosophy: optimize for the common case (honest behavior) while maintaining strong security guarantees when disputes arise.

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## Facet Compute Token (FCT)

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<summary><mark style="color:purple;">What is FCT and how do I get it?</mark></summary>

FCT (Facet Compute Token) is Facet's native gas token. It's the only way to pay for transactions on Facet.

You acquire FCT by burning ETH when sending Facet transactions to Ethereum. The process is simple:

1. Send a Facet transaction to `0xface7` on Ethereum
2. FCT is automatically minted proportional to the ETH burned for transaction data
3. Use that FCT to pay for gas on Facet

This burn-to-mint mechanism ensures FCT has no admin control - no multisig can freeze, mint, or confiscate your gas tokens. It's as permissionless as Ethereum itself.

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<summary><mark style="color:purple;">How is FCT different from bridged ETH?</mark></summary>

Traditional L2s use bridged ETH for gas, which creates critical vulnerabilities:

* Bridge admins can freeze the bridge, stopping the entire rollup
* Upgrades can change token behavior without warning
* Your ability to use the network depends on bridge operators

FCT eliminates these risks. Since it's minted algorithmically based on ETH burning, there's no bridge to freeze, no admin keys to compromise, and no dependency on any third party. Your ability to get gas tokens and use Facet is truly unstoppable.

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## Security

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<summary><mark style="color:purple;">What happens if someone reports incorrect Facet state?</mark></summary>

Facet's ZK Fault Proofs system ensures that incorrect state claims are quickly and definitively resolved:

1. **Optimistic by default**: Node operators report state updates without proofs (efficient in the common case)
2. **Single-transaction disputes**: If someone challenges a state report, the dispute is resolved in one Ethereum transaction using a ZK proof
3. **Verifiable computation**: The ZK proof mathematically guarantees the correct state computation

Additionally:

* **You can verify it yourself** by running a Facet node
* **Transactions include conditions** (like slippage limits) that prevent losses from bad data
* **No trust required**: Since the proof system is immutable and on-chain, anyone can trigger a dispute

The canonical source of truth is always the deterministic computation over Ethereum data, enforced by cryptographic proofs when needed.

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<summary><mark style="color:purple;">How does Facet guarantee it can't be stopped?</mark></summary>

Facet's unstoppability comes from its architecture:

1. **Immutable inbox**: The `0xface7` address has no known private key and no smart contract code - it can never be changed or disabled
2. **No admin keys**: No multisig controls any part of the core protocol
3. **Native gas token**: FCT can't be frozen by bridge admins since there is no bridge
4. **Fork-based upgrades**: Protocol changes require deploying a new system, not upgrading the existing one

As long as Ethereum is running and you can send transactions to it, Facet will continue operating. No group of people, no matter how powerful, can stop it.

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