Guides to launching tokens on Arc
Arc is a Layer-1 blockchain built by Circle, the issuer of USDC, for stablecoin-native financial applications. Three things set it apart: gas is paid in USDC rather than in a volatile native coin, blocks are final in under a second with no reorganisation risk, and it runs the standard EVM, so wallets, tooling and Solidity contracts work unchanged. Circle announced Arc on 12 August 2025, opened the public testnet on 28 October 2025 and launched the public mainnet on 16 September 2026. This guide collects the facts you need to use it today – chain id, RPC, how USDC gets in, what Arc still lacks – and what changed when the mainnet opened.
Arc at a glance
| Fact | Value (read off the chain 16 September 2026) |
|---|
| Built by | Circle |
| Network | Arc mainnet, public since 16 September 2026. The testnet (5042002) is a separate network and none of its addresses exist here |
| Chain id | 5042 (hex 0x13b2) |
| Gas token | USDC – there is no volatile native token |
| RPC | https://rpc.mainnet.arc.io (WebSocket wss://rpc.mainnet.arc.io); rpc.beamrpc.com answers the same chain |
| Explorer | https://explorer.arc.io – a public Blockscout since 17 September 2026 (the day before, every path on it answered a Circle SSO login) |
| Getting USDC in | No faucet – this is real money. Relay or Circle's own USDC Bridge over CCTP v2, domain 26: arc.openfair.app/bridge |
| Block time and finality | About half a second per block; deterministic, sub-second finality (Malachite BFT, a Tendermint-family protocol) |
| Execution | EVM at the Osaka hard fork, on the Reth client |
| Fee model | EIP-1559 with EWMA smoothing and a base-fee floor of 20 gwei, observed rising to about 31 gwei under launch-day load; block gas limit 30M |
| Validators | Permissioned (proof of authority); deploying contracts is permissionless |
| DEX | Uniswap v3, the canonical Uniswap Labs deployment – factory 0xf0db7b58379503491d857dB50AC9ece64c653918. Pools quote against the USDC face directly; there is no WETH |
Mainnet status – 16 September 2026: live. Circle announced the public Arc mainnet for this date in a blog post and a press release, both dated 5 August 2026, and the network answered on the day: https://rpc.mainnet.arc.io returns chain id 0x13b2, which is 5042, and blocks arrive about every half second. What is live is the chain, CCTP (Arc is domain 26) and Uniswap v3; the public block explorer at explorer.arc.io followed one day later, on 17 September 2026. status.arc.io is where Circle reports outages – what the mainnet changed.
USDC as gas: what it means in practice
On Arc the USDC balance your wallet shows is the balance that pays for gas. Native accounting uses 18 decimals, and the same balance is also exposed as a 6-decimal ERC-20 at 0x3600000000000000000000000000000000000000 – one balance, two interfaces, not two tokens. There is no wrapped USDC from Circle: the native asset already satisfies the ERC-20 interface. Fees follow EIP-1559 with a smoothed base fee and a protocol floor of 20 gwei, so set maxFeePerGas to at least 20 gwei or the mempool drops the transaction – and higher when the chain is busy: the base fee was seen at about 31 gwei under launch-day load. A tip of 0 is accepted; 1 gwei helps inclusion. Blob (type-3) transactions are not supported.
How to bridge USDC to Arc
Circle moves USDC between chains with its Cross-Chain Transfer Protocol (CCTP): USDC is burned on the source chain, Circle attests to the burn, and native USDC is minted on the destination. On Arc the minted USDC lands directly as gas-ready balance – there is no separate native coin to buy first.
Two routes, both live
Circle's own USDC Bridge does the burn-and-mint directly: hold USDC on a chain CCTP already serves – Ethereum, Base, Arbitrum, OP Mainnet, Polygon PoS, Avalanche, Solana, Unichain, Linea and others – pay that chain's gas for the approve-and-burn, wait for Circle's attestation, and receive USDC on Arc that pays for gas immediately. Nobody is in the middle, and nothing is wrapped.
Relay is the other route, and it answers the cases CCTP does not: a source chain CCTP has no domain for, an asset that is not USDC, or a hurry. It is an intent bridge, so a market maker fronts the USDC on Arc and is repaid on the source chain – one fee, one extra counterparty, seconds instead of minutes. Relay's own chain list carries Arc with deposits enabled. Our bridging guide puts both side by side.
Developers integrating CCTP v2 directly need two addresses on Arc: TokenMessengerV2 at 0x28b5a0e9C621a5BadaA536219b3a228C8168cf5d and MessageTransmitterV2 at 0x81D40F21F12A8F0E3252Bccb954D722d4c464B64. Circle's App Kit wraps the same flow – approve, burn, attestation, mint – behind one kit.bridge() call with Arc as the destination chain.
There is no mainnet faucet
USDC on Arc mainnet is real money, so nothing gives it away. The Circle faucet still exists and still serves the Arc testnet (chain id 5042002), which is a different network: an address funded there has no balance here. On mainnet the only ways in are the two bridges above, or an exchange or wallet that lists Arc as a withdrawal network. Because USDC is also the gas token, one transfer is enough to start – you do not buy a second coin for fees. If a transfer does not arrive, check your bridge's history tab first, then status.arc.io.
Add Arc to MetaMask
Open MetaMask, go to Settings, then Networks, then Add network, and choose Add a network manually. Enter exactly:
| Network name | Arc |
| New RPC URL | https://rpc.mainnet.arc.io |
| Chain ID | 5042 |
| Currency symbol | USDC |
| Block explorer URL | https://explorer.arc.io |
Save and switch to Arc. The same values work in Rabby, Coinbase Wallet and Rainbow; Circle's connect page also offers a one-click add button. One caveat from Circle's docs: a wallet that does not support custom gas tokens may label the balance "ETH" – the underlying asset is still USDC, and signing and sending work normally. In code, viem ships the chain as import { arc } from "viem/chains".
Explorer and RPC
Arc mainnet has a public block explorer: https://explorer.arc.io, a Blockscout instance on the host Circle's own docs, Uniswap's chain config and Relay all point at. It opened to anonymous readers on 17 September 2026 – the day before, every path on it, /api/v2 included, answered a Cloudflare Access redirect to Circle's SSO. One caveat for scripts rather than for readers: the /api/ paths sit behind Cloudflare's bot check, so a plain command-line request can get a “Just a moment…” challenge from some networks while the pages themselves load normally. Lookalike domains circulating under similar names are still not mirrors: one returns a 404, one is a parked domain for sale, three do not resolve at all, one sits behind an unclearable challenge, and Routescan answers "chain not supported" for 5042 from its own API. Treat a lookalike domain as a phishing risk. For anything that trades, DexScreener (dexscreener.com/arc/<pair>) and the Uniswap token page remain the better view.
Circle documents https://rpc.mainnet.arc.io as the public RPC, with mirrors at rpc.blockdaemon.mainnet.arc.io, rpc.drpc.mainnet.arc.io and rpc.quicknode.mainnet.arc.io, each with a WebSocket endpoint, plus the independent rpc.beamrpc.com; all five returned chain id 5042 when probed. Whichever you use, eth_chainId must answer 0x13b2 – if it does not, you are not on Arc. Three limits are worth knowing before you write an indexer. eth_getLogs caps a response at 2000 matches (-32602) and names the sub-range to retry; it separately caps the WIDTH of the range, somewhere between 2000 and 10000 blocks, with -32012 “requested range too large” – learn that width once and page at it, because no result-cap retry avoids it; and log history older than about a day is pruned (4444), which no narrower sub-range can recover.
What changed when the mainnet opened
- New network parameters. Chain id 5042 (hex
0x13b2) and https://rpc.mainnet.arc.io replace the testnet pair. Nothing carries over: a testnet address, a testnet contract and a testnet balance all stay on 5042002.
- Real USDC replaces faucet USDC. There is no mainnet faucet. USDC arrives over CCTP from a chain where you already hold it, over Relay from almost anywhere, or from an exchange or wallet that lists Arc.
- Fees are read from the mainnet. The 20 gwei floor held on the day and the base fee rose to about 31 gwei under load; quote gas from
eth_gasPrice rather than from a documented target.
- The explorer arrived a day after the chain. explorer.arc.io opened to anonymous readers on 17 September 2026, so a wallet's explorer field takes
https://explorer.arc.io instead of being left empty.
- Uniswap v3 is deployed. The canonical Uniswap Labs contracts are live and pools quote against the USDC face directly – so a token launched on Arc can list and trade on day one.
- The validator set is permissioned. Circle's announcement names a founding cohort that includes BlackRock, DTCC, Mastercard and Visa.
Launch a token on Arc with openfair
openfair runs on Arc mainnet at arc.openfair.app. A launch is one transaction: pay the 0.5 USDC creation fee and your token deploys as its own immutable contract. A fair launch collects 10000 USDC on a bonding curve and then lists on a Uniswap v3 pool whose liquidity is locked by construction; an instant listing needs no capital at all. Every amount is real USDC – create a token on Arc and read how the launch works.
The dependency that used to block this is resolved: Uniswap Labs' own v3 contracts are deployed on Arc, and because the pools quote against the 6-decimal USDC face rather than a wrapped native coin, openfair runs the same contract lineage here as on Stable. Launches paired with a tokenised asset stay off on Arc: they belong to a contract generation that has not been ported to the 6-decimal face yet. The soft-cap crowd launch is no longer one of them: the stable lineage's own CrowdFactory – a 25-field create with no quote asset at all – was broadcast on Arc on 17 September 2026, and a crowd launch runs here from that date. Contract verification goes to both targets: the Blockscout explorer at explorer.arc.io and Sourcify, which supports chain 5042. Developers can build with the API, SDK and MCP server.
FAQ
What is the Arc blockchain?
A Layer-1 built by Circle for stablecoin-native finance: USDC is the gas token, finality is sub-second and deterministic, and the EVM is standard, so Ethereum tooling works.
What is the Arc chain id?
Arc mainnet is 5042 (hex 0x13b2). The Arc testnet, a separate network, is 5042002 (hex 0x4cef52) – check which one your wallet is on before signing.
Is Arc mainnet live?
Yes, since 16 September 2026. The public RPC answers, blocks arrive roughly every half second, CCTP carries USDC in at domain 26 and Uniswap v3 is deployed. The public block explorer at explorer.arc.io opened a day later, on 17 September 2026.
Does Arc have its own token?
No. Gas is USDC in every Circle document, and the mainnet launched that way. Circle published an ARC whitepaper in May 2026 describing how a token could support staking and governance in a later move to proof of stake, while stating that no Arc token has been launched and no decision on one has been made.
How do I get USDC on Arc?
Bridge it: Circle's own USDC Bridge over CCTP from a chain where you already hold USDC, or Relay from almost any chain and asset. Both are on our bridging page. There is no mainnet faucet, and an exchange that lists Arc as a withdrawal network works too.
Can I launch a token on Arc today?
Yes, on mainnet, for a 0.5 USDC fee, with the curve target at 10000 USDC. Uniswap v3 is deployed on Arc, so a graduated launch lists and trades there.