> For the complete documentation index, see [llms.txt](https://docs.unstable.run/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.unstable.run/overview/stable-chain.md).

# About Stable chain

Stable is an EVM Layer-1 built specifically for **stablecoin payments**. The novel bit: it uses **USDT0** — the canonical Tether representation on the chain — as its **native gas token**.

That single design choice ripples into every UX decision Unstable makes.

## Key facts

|                     |                                                            |
| ------------------- | ---------------------------------------------------------- |
| **Chain name**      | Stable                                                     |
| **Chain ID**        | `988`                                                      |
| **Native currency** | USDT0 (18 decimals when used as gas, 6 decimals as ERC-20) |
| **Public RPC**      | `https://rpc.stable.xyz`                                   |
| **Explorer**        | [stablescan.xyz](https://stablescan.xyz)                   |
| **Finality**        | Sub-second                                                 |
| **Typical tx cost** | \~$0.002 USDT                                              |
| **Uniswap V3**      | Canonical (recognised by Uniswap Governance)               |

## Why USDT-as-gas matters

Every EVM chain has a native token — ETH on mainnet, MATIC on Polygon, BNB on BSC. That token pays for gas. It's also volatile, so:

* You need to hold two assets: the thing you're trading + the volatile gas token.
* Your gas costs bounce around in dollar terms every hour.
* Fresh users can't onboard without buying gas first, which is a whole side-quest.

Stable removes all of that. **You hold USDT0. You pay gas in USDT0. Every price you see is a real dollar.**

## The USDT0 dual interface

USDT0 shows up twice in the chain:

1. **As the native currency** — 18 decimals, spent via `msg.value`, paid as gas.
2. **As an ERC-20** at `0x779Ded0c9e1022225f8E0630b35a9b54bE713736` — 6 decimals, transferable, approvable, permit-signable.

Both interfaces access the same underlying balance. When Unstable's contracts move USDT0 around, they use the ERC-20 side (because that's what Uniswap V3 speaks). Your wallet balance is the same either way.

{% hint style="info" %}
Coming from a chain like Ethereum? Think of USDT0 the way you think of ETH — except priced $1, always.
{% endhint %}

## Uniswap V3 on Stable

Uniswap V3 is deployed as the canonical DEX on Stable, maintained by Protofire. Same contracts, same interfaces, same tooling — the only meaningful difference is that pools are quoted in USDT0 instead of WETH.

Unstable uses these canonical V3 contracts directly:

| Contract                          | Address                                      |
| --------------------------------- | -------------------------------------------- |
| V3 Factory                        | `0x88F0a512eF09175D456bc9547f914f48C013E4aA` |
| NonfungiblePositionManager (NFPM) | `0x3BdC3437405f7D801b6036532713fc1F179136a6` |
| SwapRouter02                      | `0x32eaf9B5d5F2CD7361c5012890C943D7de84C22a` |
| QuoterV2                          | `0xb070179E7032CdA868b53e6C1742F80c9e940d1A` |

That's it — no forked routers, no proprietary AMM. If your bot or wallet already speaks Uniswap V3, it already speaks Unstable.

## Next

* [Getting USDT0](/for-users/get-usdt0.md) — how to top up
* [Connecting your wallet](/for-users/connect-wallet.md) — supported wallets & chain-add flow


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