This desk expands the reference’s Circle/Arc page to include EURC, Circle’s euro-denominated stablecoin. USDC is dollar-denominated. EURC is the issuer ticker intended here; there is no separate ERUC asset in this guide.
Stablecoins, tokenized Bitcoin and proof-of-work native coins are different instruments. Their issuers, redemption terms, host chains and consensus assumptions belong beside their symbols.
The notebook / 01
Arc: current documentation, distinct consensus
Arc’s connection documentation currently lists mainnet chain ID 5042. Arc is EVM-compatible and uses USDC as its native gas asset. Its consensus documentation describes permissioned Proof-of-Authority validators and Tendermint-style BFT voting through Malachite; it is not Bitcoin proof of work.
This is a current documentation check, not an independent uptime, throughput or finality measurement. The older reference’s August 2025 product-vision description remains historical and is not used to infer today’s status.
Arc: network connection reference ↗Arc: consensus and validator model ↗
The notebook / 02
One USDC balance, two interfaces
Arc exposes a single USDC balance through an 18-decimal native interface and a 6-decimal ERC-20 interface. These are two views of one balance, not two spendable reserves. EURC is a separate euro-denominated ERC-20 asset, not Arc’s native gas asset.
The notebook / 03
USDC and EURC: backing is an issuer claim
Circle describes reserve assets and publishes periodic assurance reports. USDC reserve reporting covers cash and short-duration US government instruments; EURC reserve reporting concerns euro deposits. The issuer’s backing disclosure is distinct from an exchange price, a DeFi pool balance or guaranteed redemption access.
Direct issuer services have eligibility and supported-network requirements. A bridged representation should not be assumed interchangeable with a native issuer token.
Circle: reserve transparency and reports ↗Circle Mint: supported chains and currencies ↗
The notebook / 04
Use the current contract registry
Circle’s current contract and Mint registries include Arc and Base for USDC/EURC. A shorter marketing network list should not override the dated registry used for a technical identity check. Mainnet and testnet entries are separate; a test token is not a claim on real currency.
Arc, Base, CCTP transport and a Morpho deployment each have their own support matrix. A documented stablecoin on a chain does not prove a specific collateral market exists there.
Circle: USDC contract registry ↗Circle: EURC contract registry ↗Circle Mint: supported chains and currencies ↗
The notebook / 05
The policy conversation has its own date
Circle published its response to the European Commission’s MiCA review consultation on October 1, 2026. It is the issuer’s policy position, not an adopted regulation or a statement that every token or service is available in every jurisdiction. Read that dated submission alongside the official legislative record.
Circle: response to the MiCA review consultation · October 1, 2026 ↗