Top 7 C# ETL Projects

LINQ to DB

7 2,558 8.7 C#

Linq to database provider.

Project mention: LiteDB: A .NET embedded NoSQL database | news.ycombinator.com | 2022-11-08

Before checking this out, people might want to take a look through the issues and pull requests of which there are 500+ and 50+ respectively [1]. I was really optimistic about this project and it was headed in a great direction, but it's not in a production ready state, and it seems that the main guy behind it has decided to move onto other things. It's been about a year since there was any significant activity.
I just mention this because a lot of these little issues might only become more apparent after integrating the db into your project and so it can be a bit annoying. I ended up swapping to Linq2DB [1]. It's something, more or less, similar offering an ORM/LINQ type system as well as the ability to also use direct SQL if desired. But the neat thing is that it also uses a standardized API for the LINQ query language, so you can do things like swap from SQLite to PostgreSQL in one* line of code, so long as you're not using any provider specific extensions.
[1] - https://github.com/mbdavid/LiteDB
[2] - https://github.com/linq2db/linq2db
Cinchoo ETL

0 636 4.8 C#

ETL framework for .NET (Parser / Writer for CSV, Flat, Xml, JSON, Key-Value, Parquet, Yaml, Avro formatted files)
SonarQube

www.sonarqube.org
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SmartCode

0 545 3.1 C#

SmartCode = IDataSource -> IBuildTask -> IOutput => Build Everything!!!
bulk-writer

0 229 2.1 C#

Provides guidance for fast ETL jobs, an IDataReader implementation for SqlBulkCopy (or the MySql or Oracle equivalents) that wraps an IEnumerable, and libraries for mapping entites to table columns.
Reactive ETL

0 67 6.2 C#

Reactive ETL is a rewrite of Rhino ETL using the reactive extensions for .Net.
postgresql-to-mssql

1 7 10.0 C#

Migrate postgresql data to sql server on the fly!

Project mention: SQL server to postgreSQL migration | reddit.com/r/dotnet | 2023-02-23

I've created a tool if you want to migrate from PostgreSQL to SQL Server instead: https://github.com/sanamhub/postgresql-to-mssql
DataPowerTools

1 6 10.0 C#

Bridging the gap between IEnumerable and IDataReader, plus fast ETL.

Project mention: What do you use for Data Wrangling / ETL? | reddit.com/r/dotnet | 2022-12-02

I created a lib https://github.com/nh43de/DataPowerTools for this purpose (basically a lot of extensions around IDataReader), but I haven't had the time to really maintain or document it properly. Basically, there are readers: ExcelReader, CsvReader, etc. that implement IDataReader, a standard ADO.NET interface, and then extension methods can be called on IDataReader to add/modify/transform/lookup columns. Once the (possibly transformed) IDataReader is obtained it can then be used to write the data somewhere else, or analyzed further e.g. to create a table to fit the transformed data. Currently supported destinations are Excel, Sql Server, SqlLite, Csv, or any destination that takes in an IDataReader. It's highly performant and in production in a lot of places.
InfluxDB

www.influxdata.com
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NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020). The latest post mention was on 2023-02-23.