Multichain Service

The Multichain service aggregates hashes and entities from multiple chains behind one endpoint.

• single search across chains
• token discovery without chain selection
• unified UX for hashes

Handle	What it gives you	Why it is useful
GET https://api.blockscout.com/multichain/api/v1/clusters/multichain/chains	List of chains supported by Multichain service	Required to know which chains are indexed in multichain
GET https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q={query}&apikey=YOUR_KEY	Multichain search results for addresses, blocks, transactions, tokens, NFTs, domains, and dapps	One search box across all supported chains

Examples

Multichain token search

Use for:

• token discovery across all supported chains
• resolving multiple deployments (e.g. USDC on Ethereum, Arbitrum, Base)
• showing correct contract per chain

curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q=usdc&apikey=YOUR_KEY"

Multichain address / tx lookup

Use for:

• detecting which chain an address or transaction belongs to
• building a universal search bar
• avoiding chain selection UX

Example (address):

curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&apikey=YOUR_KEY"

Example (transaction):

curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q=0x4b03d69654a965de6a2fe907856a0e39a51a8ae25d9ddb8d97aa16ba5c1835e1&apikey=YOUR_KEY"

Minimal flow

1. fetch supported chains

curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/chains?apikey=YOUR_KEY"

2. user inputs query
3. call search:quick
4. render results grouped by type + chain

TypeScript example

const API_KEY = process.env.BLOCKSCOUT_API_KEY ?? "YOUR_KEY";
const QUERY = process.argv[2] ?? "usdc";

const base = "https://api.blockscout.com/multichain/api/v1/clusters/multichain";

async function getJson(url: string) {
  const res = await fetch(url);
  return res.json();
}

async function main() {
  const chains = await getJson(`${base}/chains?apikey=${API_KEY}`);
  console.log("Supported chains:", Object.keys(chains).length);

  const searchUrl =
    `${base}/search:quick?q=${encodeURIComponent(QUERY)}&apikey=${API_KEY}`;

  const data = await getJson(searchUrl);

  console.log(`\nQuery: ${QUERY}\n`);

  for (const token of data.tokens ?? []) {
    const chains = Object.keys(token.chain_infos ?? {});
    console.log(`${token.symbol} | ${token.address_hash}`);
    console.log(`chains: ${chains.join(", ")}`);
  }

  console.log("\nAddresses:", (data.addresses ?? []).length);
  console.log("Transactions:", (data.transactions ?? []).length);
}

main();

Supported chains

Fetch dynamically:

GET https://api.blockscout.com/multichain/api/v1/clusters/multichain/chains

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