NBatch

A lightweight batch processing framework for .NET, inspired by Spring Batch.

📖 Full Documentation — guides, API reference, and examples.

NBatch gives you a declarative, step-based pipeline for ETL jobs, data migrations, and scheduled tasks. Wire up readers, processors, and writers — NBatch handles chunking, error skipping, progress tracking, and restart-from-failure.

Packages

Package	Description
NBatch	Core framework — interfaces, chunking, skip policies, CsvReader, DbReader/DbWriter, DI, hosted service
NBatch.EntityFrameworkCore	EF Core job store for restart-from-failure (SQL Server, PostgreSQL, SQLite, MySQL/MariaDB)

dotnet add package NBatch dotnet add package NBatch.EntityFrameworkCore # only if you need persistent job tracking

Examples

var job = Job.CreateBuilder("ETL") .AddStep("extract-transform", step => step .ReadFrom(new CsvReader<Order>(...)) .WriteTo(new DbWriter<Order>(...)) .WithChunkSize(100)) .AddStep("notify", step => step .Execute(() => SendEmail())) .Build();

With SQL-backed job store for restart-from-failure

var job = Job.CreateBuilder("csv-import") .UseJobStore(connStr, DatabaseProvider.SqlServer) // optional — enables restart-from-failure .AddStep("import", step => step .ReadFrom(new CsvReader<Product>("data.csv", mapFn) .ProcessWith(p => new Product { Name = p.Name.ToUpper(), Price = p.Price }) .WriteTo(new DbWriter<Product>(dbContext)) .WithSkipPolicy(SkipPolicy.For<FormatException>(maxSkips: 5)) .WithChunkSize(100)) .AddStep("notify", step => step .Execute(() => SendEmail())) .Build(); await job.RunAsync();

With Dependency Injection & Hosted Service

builder.Services.AddNBatch(nbatch => { nbatch.AddJob("csv-import", (sp, job) => job .AddStep("import", step => step .ReadFrom(new CsvReader<Product>("data.csv", mapFn)) .WriteTo(new DbWriter<Product>(sp.GetRequiredService<AppDbContext>())) .WithChunkSize(100))) .RunEvery(TimeSpan.FromHours(1)); });

Highlights

• Chunk-oriented processing — read, transform, and write in configurable batches
• Skip policies — skip malformed records instead of aborting the job
• Restart from failure — SQL-backed job store resumes where a crashed job left off
• Tasklet steps — fire-and-forget work (send an email, call an API, run a stored proc)
• Lambda-friendly — processors and writers can be plain lambdas; no extra classes needed
• DI & hosted service — AddNBatch(), RunOnce(), RunEvery() for background jobs
• Multi-target — .NET 8, .NET 9, and .NET 10
• Provider-agnostic — SQL Server, PostgreSQL, SQLite, or MySQL for the job store; any EF Core provider for your data

Documentation

See the full documentation for guides, API reference, and examples:

• Core concepts — jobs, steps, readers, writers, processors
• Readers & writers — CsvReader, DbReader, DbWriter, FlatFileItemWriter
• Skip policies — error handling and skip limits
• Job store — persistent tracking and restart-from-failure
• DI & hosted service — AddNBatch(), IJobRunner, RunOnce(), RunEvery()
• Listeners — job and step lifecycle hooks
• API reference — all public types and methods
• Examples — CSV-to-DB, DB-to-file, multi-step, DI, hosted service

Running locally

# Start the test database (SQL Server via Docker) cd src && docker compose up -d # Build & run the demo console app dotnet build dotnet run --project NBatch.ConsoleApp # Run tests dotnet test

Contributing

1. Fork the repo
2. Create a feature branch: git checkout -b my-feature
3. Commit your changes: git commit -m "Add my feature"
4. Push: git push origin my-feature
5. Open a pull request

License

See LICENSE for details.