Blockchain Explorer

Blockchain Explorer

Nethereum.Explorer is a Blazor Server Razor Class Library (RCL) that provides a complete blockchain explorer for Ethereum-compatible chains. It renders blocks, transactions, accounts, contracts, tokens, NFTs, internal transactions, event logs, an EVM debugger, and a MUD World browser — all with ABI decoding and wallet integration via EIP-6963.

NuGet: Nethereum.Explorer

dotnet add package Nethereum.Explorer

DI Setup

Register explorer services in Program.cs:

using Nethereum.Explorer.Services;
using Nethereum.BlockchainStore.Postgres;
using Nethereum.BlockchainStorage.Token.Postgres;

var builder = WebApplication.CreateBuilder(args);

// Core explorer services (required)
builder.Services.AddExplorerServices(builder.Configuration);

// Blockchain storage — provides block/transaction/contract repositories
var connString = builder.Configuration.GetConnectionString("PostgresConnection")!;
builder.Services.AddPostgresBlockchainStorage(connString);

// Token storage — provides token balances, NFT inventory, transfer logs, metadata
builder.Services.AddTokenPostgresRepositories(connString);

var app = builder.Build();

// Map API endpoints
app.MapTokenApiEndpoints();
app.MapContractApiEndpoints();
app.UseRateLimiter();

app.Run();

Without AddPostgresBlockchainStorage, the explorer falls back to direct RPC queries. Without AddTokenPostgresRepositories, token pages show a "Token indexing not configured" message via NullTokenExplorerService.

Configuration

All options are bound from appsettings.json section Explorer:

{
  "Explorer": {
    "RpcUrl": "http://localhost:8545",
    "ChainName": "DevChain",
    "ChainId": 31337,
    "CurrencySymbol": "ETH",
    "CurrencyName": "Ether",
    "CurrencyDecimals": 18,
    "BlockExplorerUrl": null,

    "ExplorerTitle": "Nethereum Explorer",
    "ExplorerBrandName": "Nethereum",
    "ExplorerBrandSuffix": "Explorer",
    "LogoUrl": null,
    "FaviconUrl": null,

    "ApiKey": null,

    "EnableMud": true,
    "EnableTokens": true,
    "EnableTracing": true,
    "EnableInternalTransactions": true,
    "EnablePendingTransactions": false,
    "EnableEvmDebugger": true,

    "RpcRequestTimeoutSeconds": 30,

    "AbiSources": {
      "SourcifyEnabled": true,
      "FourByteEnabled": false,
      "EtherscanEnabled": false,
      "EtherscanApiKey": null,
      "LocalStorageEnabled": false,
      "LocalStoragePath": null,
      "SourceBasePath": null
    }
  }
}

ExplorerOptions Properties

AbiSourceOptions

ABI sources are chained as a composite: in-memory cache is checked first, then each enabled source in order (local -> Sourcify -> Etherscan -> 4Byte).

Features

• Block browsing — paginated block list, block detail with transactions
• Transaction browsing — paginated transaction list, full transaction detail with decoded input data, event logs, gas breakdown, state diffs, blob data, authorization lists
• Pending transactions — live pending transaction feed (when enabled)
• Account pages — balance, transaction history with direction filtering, internal transactions, token holdings, NFT inventory
• Contract interaction — ABI-decoded read/write functions, event log decoding, contract detail with source metadata
• Token pages — ERC-20 balances, ERC-721/ERC-1155 NFT inventory, transfer history per address or contract
• Internal transactions — decoded internal calls with method signatures
• EVM step debugger — opcode-level transaction trace with stack, memory, and storage inspection
• MUD World browser — list MUD worlds, browse tables, view decoded records, query normalised tables with filters
• Global search — resolves addresses, transaction hashes, block numbers, ENS names
• Recent searches — client-side search history
• CSV export — export transaction and token data
• QR codes — address QR code display
• Wallet integration — EIP-6963 wallet discovery, authentication state, send transactions from contract interaction UI
• Localization — English and Spanish translations
• Rate limiting — built-in fixed-window rate limiter on API endpoints (100 req/min)
• Toast notifications — success/error feedback

Pages Reference

API Endpoints

Token API (/api/tokens)

Contract API (/api/contracts)

Upload ABI example:

curl -X POST http://localhost:5000/api/contracts/0x1234.../abi \
  -H "Content-Type: application/json" \
  -H "X-Api-Key: your-key" \
  -d '{"abi": "[{\"type\":\"function\",...}]", "name": "MyContract"}'

Batch upload:

curl -X POST http://localhost:5000/api/contracts/batch \
  -H "Content-Type: application/json" \
  -H "X-Api-Key: your-key" \
  -d '{"contracts": [{"address": "0x...", "abi": "[...]", "name": "Token"}, ...]}'

Branding Customization

Set branding via ExplorerOptions:

{
  "Explorer": {
    "ExplorerTitle": "My Chain Explorer",
    "ExplorerBrandName": "MyChain",
    "ExplorerBrandSuffix": "Explorer",
    "LogoUrl": "/images/logo.svg",
    "FaviconUrl": "/images/favicon.ico",
    "CurrencySymbol": "MYC",
    "CurrencyName": "MyCoin",
    "ChainName": "MyChain Mainnet"
  }
}

MUD Browser Setup

The MUD browser requires MUD Entity Framework repositories. Register them alongside the explorer:

using Nethereum.Mud.Repositories.EntityFramework;

builder.Services.AddMudPostgresRepositories(connString);

The explorer's IMudExplorerService automatically detects whether MUD repositories are available. When EnableMud is true and repositories are registered, the MUD nav items and pages appear. The browser supports:

• Listing all MUD World contract addresses
• Browsing tables per World with key/value field schemas
• Viewing raw and decoded records
• Querying normalised tables with field-level filter conditions (equals, greater than, less than, contains)
• Schema introspection via on-chain getSchema calls

Core Services

All query services are registered as scoped. ABI storage uses a singleton composite chain with in-memory cache.

Minimal Standalone Example

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddRazorComponents().AddInteractiveServerComponents();
builder.Services.AddExplorerServices(builder.Configuration);

var app = builder.Build();
app.UseStaticFiles();
app.UseAntiforgery();
app.UseRateLimiter();
app.MapTokenApiEndpoints();
app.MapContractApiEndpoints();
app.MapRazorComponents<App>().AddInteractiveServerRenderMode();
app.Run();

With appsettings.json:

{
  "Explorer": {
    "RpcUrl": "http://localhost:8545",
    "ChainName": "Local DevChain",
    "ChainId": 31337
  }
}

This gives a fully functional explorer against a local dev chain with Sourcify ABI resolution, no database required. Add AddPostgresBlockchainStorage and AddTokenPostgresRepositories for indexed data.