A block explorer for two chains at once.

Explorer is a block explorer that reads two chains as one system. A rollup is two consensus machines pretending to be one: blocks land on the L2, settlement lands on the host, and a single order can start on one side and finish on the other. Most explorers show you half of that.

The real problem is ordering. An intent order gets indexed before the fill that satisfies it exists, so the index cannot just sort by timestamp. It has to hold A open until B arrives: A after B, even when A came in first. Once you can do that, any action spread across two systems collapses into one event you can query. A fill, a bridge, any distributed action becomes a market event with atomicity: either both sides happened or the event does not exist.

I built it on the Signet testnets because they had real activity worth watching: intent orders under ERC-7521, builders producing blocks, fillers competing for flow, lending protocols on top. The questions were all relational. Who filled this order. Which builder made this block. What the MEV exposure is once you add both chains together.

The two views run side by side with live polling. Orders get attributed to the fillers and solvers that touched them, each transaction gets an MEV risk score, and the canonical network token stays visually separate from whatever a community deployed on a Tuesday.

React 19 and TanStack, live at explorer.testnet.build. A sibling at open-explorer.testnet.build runs the same shell across five OP Stack testnets with a chain-aware search layer that keeps cached results from leaking between networks. The honest limit: this is testnet tooling. The activity is rehearsal activity, and nothing here has been tested against mainnet volume or real money.