Eel is a toolkit for manipulating data in the hadoop ecosystem. By hadoop ecosystem we mean file formats common to the big-data world, such as parquet, orc, csv in locations such as HDFS or Hive tables. In contrast to distributed batch or streaming engines such as Spark or Flink, Eel is an SDK intended to be used directly in process. Eel is a lower level API than higher level engines like Spark and is aimed for those use cases when you want something like a file API. Here are some of our notes comparing eel to other tools that offer functionality similar to eel.