Knowledge Base

• Is Arc a rollup? What is it built from?Arc is Circle's standalone layer-1 blockchain, with its own validator set: Malachite BFT consensus over a Reth execution layer, settling in USDC. It is not a rollup and does not post to another chain.
• How many confirmations should I wait for?None. Arc commits a block once more than two thirds of the validator set has precommitted it; that block can never be reorganised. There is no confirmation count, no reorg risk, and every page keyed to a block height is permanent.

• Why does the same USDC balance appear with 18 decimals and with 6?Arc pays gas in USDC. The native balance carries 18 decimals and the ERC-20 face at 0x3600…0000 carries 6; a precompile holds them at parity, so the two figures are one balance and differ by exactly 10^12.

• Where is the pending transactions page? My transaction isn't showing up.Arc exposes no public mempool: pending-transaction subscriptions and txpool methods are disabled, and blocks land twice a second. Arcscan therefore has no pending feed and no pending state — a transaction is either in a block or unknown.
• Why does Arcscan not have the page I expected from another explorer?A list of the explorer features Arc makes meaningless — pending transactions, confirmations, uncles, blobs, fiat conversion — and the ones that are genuinely not built yet.

These articles cover the chain, not general blockchain concepts — there are better explainers of what a hash is than anything Arcscan would write. For the API contract see the API reference; for how current our view of the chain is, see network status; for anything else, the contact routes are listed.