What is a .arrow file?
Apache Arrow IPC File · Data · Apache Software Foundation · 2016
Apache Arrow is an in-memory columnar data format, and its file form (also known as Feather) stores that layout on disk. It lets tools share tabular data with zero copying, so reads are extremely fast.
What is a .arrow file used for?
An Arrow IPC file starts and ends with the magic ARROW1 around a columnar record batch. Because the on-disk layout matches the in-memory one, loading is nearly instant with no parsing, unlike CSV.
It is the backbone of the modern data stack (pandas, Polars, DuckDB, Spark). The .feather extension is the same format under an older name, favoured for fast local caching of data frames.
How to open a .arrow file
The .arrow format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .arrow file.
Windows
- Python (pyarrow, pandas)
- R (arrow)
- Polars
macOS
- Python (pyarrow, pandas)
- R (arrow)
- Polars
Linux
- Python (pyarrow, pandas)
- DuckDB
- Polars
How to convert a .arrow file
You can convert a .arrow file to parquet, csv, json using a conversion tool or the export menu of an app that opens it.
.arrow file signature (magic bytes)
Programs recognise a .arrow file by the bytes at the start of the file, not by its name. These are the signatures for Arrow. For a full breakdown, see the Arrow file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 41 52 52 4F 57 31 | 0 | 'ARROW1' |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .arrow file?
Apache Arrow is an in-memory columnar data format, and its file form (also known as Feather) stores that layout on disk. It lets tools share tabular data with zero copying, so reads are extremely fast.
What is the difference between Arrow and Parquet?
Arrow is a fast in-memory and IPC format for moving data between tools. Parquet is a compressed on-disk format for long-term columnar storage. They are complementary and interoperate.
Is Feather the same as Arrow?
Yes. Feather is the file form of the Apache Arrow format; a .feather file is an Arrow IPC file, popular for fast caching of data frames.
How do I open an .arrow file?
Read it with pyarrow or pandas in Python, the arrow package in R, or Polars. There is no document viewer; it is tabular data for code.
Related formats
Sources
Details on this page were checked against authoritative references: