Data & Indexing

Nethereum provides a complete pipeline for crawling blockchain data, persisting it to relational databases, indexing token activity, and exploring the results through a Blazor UI. The stack is modular — use the processing engine alone for custom ETL, add database storage for persistence, layer on token indexing for ERC-20/721/1155 tracking, and embed the explorer for a ready-made UI.

What Can I Do?

I want to...	Guide	Packages
Crawl blocks and process transactions	Blockchain Processing	Nethereum.BlockchainProcessing
Process typed event logs from contracts	Blockchain Processing	Nethereum.BlockchainProcessing
Track progress and resume after restart	Blockchain Processing	Nethereum.BlockchainProcessing
Handle chain reorganisations	Blockchain Processing	Nethereum.BlockchainProcessing
Persist blocks/txs/logs to PostgreSQL	Database Storage	BlockchainStore.Postgres + Processors.Postgres
Persist to SQL Server or SQLite	Database Storage	BlockchainStore.SqlServer/Sqlite + Processors
Run indexing as a hosted service	Database Storage	BlockchainStorage.Processors.*
Index internal transactions (traces)	Database Storage	Processors.* + debug RPC
Index ERC-20 token transfers	Token Indexing	BlockchainStorage.Token.Postgres
Index ERC-721 NFT ownership	Token Indexing	BlockchainStorage.Token.Postgres
Index ERC-1155 multi-token balances	Token Indexing	BlockchainStorage.Token.Postgres
Build a blockchain explorer	Explorer	Nethereum.Explorer
Interact with contracts via ABI-decoded UI	Explorer	Nethereum.Explorer + DataServices
Debug EVM execution step-by-step	Explorer	Nethereum.Explorer
Browse MUD World tables in a UI	Explorer	Nethereum.Explorer + Mud.Repositories.Postgres

Quick Start — Process Event Logs

var processor = web3.Processing.Logs.CreateProcessor<TransferEventDTO>(
    action: log =>
    {
        Console.WriteLine($"Transfer: {log.Event.From} -> {log.Event.To}, Amount: {log.Event.Value}");
        return Task.CompletedTask;
    },
    minimumBlockConfirmations: 12,
    contractAddresses: new[] { contractAddress }
);

await processor.ExecuteAsync(
    startAtBlockNumberIfNotProcessed: 18000000,
    cancellationToken: cancellationToken.Token
);

Quick Start — Aspire Template (Recommended)

The fastest way to get a running indexer + explorer is the Aspire template:

dotnet new install Nethereum.Aspire.TemplatePack
dotnet new nethereum-devchain -n MyExplorer
cd MyExplorer
dotnet run --project AppHost

This gives you DevChain + Indexer + Explorer + PostgreSQL, all orchestrated by .NET Aspire with service discovery. Open the Aspire dashboard to see all services running. See the Explorer guide for details.

Quick Start — Manual Setup (Indexer + Explorer)

var builder = WebApplication.CreateBuilder(args);
var conn = "Host=localhost;Database=blockchain;Username=postgres;Password=secret";

// Index blocks, transactions, logs
builder.Services.AddPostgresBlockchainProcessor(builder.Configuration, conn);
builder.Services.AddPostgresInternalTransactionProcessor();

// Index ERC-20/721/1155 tokens
builder.Services.AddTokenLogPostgresProcessing(builder.Configuration, conn);
builder.Services.AddTokenDenormalizerProcessing(builder.Configuration, conn);
builder.Services.AddTokenBalanceAggregationProcessing(builder.Configuration, conn);

// Blazor explorer UI
builder.Services.AddExplorerServices(builder.Configuration);

var app = builder.Build();
app.MapRazorComponents<App>().AddInteractiveServerRenderMode();
app.Run();

Architecture

BlockchainProcessing (pipeline engine)
├── BlockCrawlOrchestrator — block-by-block with txs, receipts, logs
├── LogOrchestrator — batch eth_getLogs across large ranges
└── InternalTransactionOrchestrator — debug_traceTransaction

BlockchainStore.EFCore (storage abstraction)
├── BlockchainDbContextBase — entity models, indexes
├── Repository interfaces — IBlockRepository, ITransactionRepository, etc.
└── Provider implementations — Postgres, SqlServer, Sqlite

BlockchainStorage.Processors (hosted services)
├── BlockchainProcessingHostedService — indexes blocks/txs/logs
└── InternalTransactionProcessingHostedService — indexes call traces

BlockchainStorage.Token.Postgres (token pipeline)
├── TokenLogPostgresProcessingService — capture Transfer events
├── TokenDenormalizerService — decode into typed records
└── TokenBalanceRpcAggregationService — aggregate balances via RPC

Nethereum.Explorer (Blazor UI)
├── Block/transaction/account/contract browsing
├── ABI-decoded contract interaction
├── Token balances, NFT inventory, transfers
├── EVM debugger with Solidity source mapping
└── MUD World browser

Database Providers

Package	Provider
Nethereum.BlockchainStore.Postgres	PostgreSQL
Nethereum.BlockchainStore.SqlServer	SQL Server
Nethereum.BlockchainStore.Sqlite	SQLite

Guides

• Blockchain Processing — Crawl blocks, transactions, and event logs with progress tracking
• Database Storage — Persist to PostgreSQL, SQL Server, or SQLite with hosted services
• Token Indexing — Index ERC-20/721/1155 transfers and aggregate balances
• Explorer — Embed a full-featured Blazor blockchain explorer