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

# FAQ

> Get quick answers to common onboarding questions: what Stable is, how to start, what differs from Ethereum, and where to find deeper docs.

## Getting started

**What is Stable?**

A Layer 1 where USDT0 is the native gas token and settlement asset. Standard EVM tooling works unchanged.

**Who is Stable for?**

Three builder profiles: payment and wallet teams moving USDT0, smart contract developers deploying to an EVM, and infrastructure teams running nodes or RPC. The [Learn overview](/en/explanation/learn-overview) has a card per path.

**Where should I start: Payments, Contracts, AI/Agents, or Infrastructure?**

* Moving USDT0 or building payment flows → [Payments](/en/explanation/payments-overview).
* Deploying contracts → [Contracts](/en/explanation/contracts-overview).
* Wiring AI editors or building agent-paid services → [AI/Agents](/en/explanation/ai-agents-overview).
* Running nodes or covering gas for users → [Infrastructure](/en/explanation/integrate-overview).

If you haven't connected to testnet yet, start with [Quick start](/en/tutorial/quick-start).

## Technical

**Is Stable EVM-compatible?**

Yes. Solidity, Vyper, Foundry, Hardhat, ethers, viem, and the `eth_*` JSON-RPC methods all work unchanged. Four behaviors differ from Ethereum — see [Differences from Ethereum](/en/explanation/ethereum-comparison).

**Why is USDT0 the gas token?**

So you pay fees in the asset you're already transacting in. No second token to fund, and fees stay denominated in a stablecoin. The protocol also optimizes USDT0-heavy workloads through guaranteed blockspace and transfer aggregation; see [Core concepts](/en/explanation/core-concepts).

**How do I get USDT0?**

* **Testnet:** use the faucet at [faucet.stable.xyz](https://faucet.stable.xyz), or bridge Test USDT from Ethereum Sepolia. Walkthrough in [Get testnet USDT0](/en/how-to/use-faucet).
* **Mainnet:** bridge USDT0 from another chain via LayerZero, or acquire through an exchange or custodian.

**What changes when I port a contract from Ethereum?**

Most contracts deploy unchanged. Three things to fix if they apply:

* Don't mirror native balance in internal variables. `transferFrom` can drain native without calling the contract.
* Don't transfer to `address(0)`. Both native and ERC-20 transfers to zero revert.
* Don't rely on `EXTCODEHASH` for address-reuse detection. Permit-based approvals change native balance without a nonce increment.

Full checklist: [USDT0 behavior on Stable](/en/explanation/usdt0-behavior).

## Resources

**Where do I find tokenomics, roadmap, and architecture?**

* [Tokenomics](/en/reference/tokenomics): STABLE supply, allocation, and vesting.
* [Technical roadmap](/en/explanation/technical-roadmap): phased optimization plan.
* [Tech overview](/en/explanation/tech-overview): StableBFT, Stable EVM, StableDB, and RPC design.
* [USDT-specific features](/en/explanation/usdt-features-overview): detail on gas, blockspace, aggregation, and confidential transfer.

**Where do I go for help?**

* [Developer assistance](/en/reference/developer-assistance): FAQ and reference pointers.
* [Discord](https://discord.gg/stablexyz): community support and protocol updates.
* `bizdev@stable.xyz`: partnership and integration conversations.

## Next recommended

<CardGroup cols={2}>
  <Card title="Quick start" icon="rocket" href="/en/tutorial/quick-start">
    Send a first transaction on testnet.
  </Card>

  <Card title="Core concepts" icon="book-open" href="/en/explanation/core-concepts">
    Learn the four core concepts you need before you build.
  </Card>

  <Card title="Learn overview" icon="route" href="/en/explanation/learn-overview">
    Pick the docs path that fits what you're building.
  </Card>

  <Card title="Production readiness" icon="shield-check" href="/en/how-to/production-readiness">
    Validate an integration before shipping to mainnet.
  </Card>
</CardGroup>