> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blockscout.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 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

```bash theme={null}
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):**

```bash theme={null}
curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&apikey=YOUR_KEY"
```

**Example (transaction):**

```bash theme={null}
curl "https://api.blockscout.com/multichain/api/v1/clusters/multichain/search:quick?q=0x4b03d69654a965de6a2fe907856a0e39a51a8ae25d9ddb8d97aa16ba5c1835e1&apikey=YOUR_KEY"
```

## Minimal flow

1. fetch supported chains

```bash theme={null}
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

```ts theme={null}
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:

```bash theme={null}
GET https://api.blockscout.com/multichain/api/v1/clusters/multichain/chains
```

***