SmartQueryTools

Arrow Viewer Online

View and inspect Arrow files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.

About the Arrow viewer

Arrow IPC files, also saved as .feather or .ipc, come from pyarrow, pandas.to_feather, polars, R's arrow package and many query engines. They are binary and cannot be inspected in a text editor. The Arrow viewer reads the file in the browser and shows the schema, the total row count and the first 500 rows. It is a quick check on what a notebook or service wrote out.

Both Arrow framings are accepted: the file format, which starts with the ARROW1 marker and is also Feather version 2, and the streaming format. Types in the schema panel are shown using SQL names, so Int64 appears as BIGINT, Utf8 as VARCHAR and Float64 as DOUBLE. Dictionary-encoded columns, such as pandas categoricals, show as their value type. Old Feather version 1 files from before 2020 use a different layout and do not open. Files with several record batches are combined into one table.

What to check when you open a Arrow file

  • The file opens at all. An error often means Feather version 1 or a file that was only partly written.
  • Categorical columns show their text values, not integer codes.
  • Integer columns that contained missing values in pandas are integers, not DOUBLE.
  • Timestamp columns are TIMESTAMP with the precision you expect.
  • The row count matches the length of the DataFrame or table that wrote the file.

Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.

Frequently Asked Questions

Can the Arrow viewer open Feather files?

Yes, Feather version 2 files, which is what pandas and pyarrow have written by default since 2020. LZ4 and Zstandard compressed files open too. The file picker lists .arrow, .arrows, .ipc and .feather files. Feather version 1 files are not supported.

Why are the types shown as BIGINT and VARCHAR instead of Int64 and Utf8?

The file is loaded into a SQL table for display, and the schema panel shows the SQL names. Int64 maps to BIGINT, Float64 to DOUBLE, Utf8 to VARCHAR and Bool to BOOLEAN. The Arrow file itself is not changed.

Does the viewer read Arrow streaming files?

Yes. Both the IPC file format and the IPC stream format are accepted, including multiple record batches. The batches are combined into one table.

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