Which protobuf files does this accept?

Protobuf messages serialized with the standard protobuf JSON mapping (protojson) — for example a `to_json()` dump of a message, or a JSON array produced by protobuf tooling. Files up to 5 MB.

Will a binary .pb wire-format file work?

No. Binary protobuf cannot be decoded without the message schema and a protobuf compiler, so this converter reads protobuf data that has already been serialized to the JSON mapping. Most protobuf libraries can produce that with one call.

How are nested messages and repeated fields handled?

Records — top-level messages or elements of a repeated field — become rows. Their scalar fields become columns. Nested messages and repeated scalar fields stay intact as JSON text inside the cell.

What happens when a record is missing a field?

Missing fields become empty cells. Columns are collected from every record in the file, so nothing is silently dropped.

Convert protobuf data to CSV online

Need a spreadsheet of protobuf records without writing a parser? This page turns record-oriented protobuf data into CSV with one upload.

How to convert protobuf data

Upload a file with protobuf messages serialized as JSON (protojson), up to 5 MB.
Press Convert file.
Copy or download the CSV result.

What you get

A ready-to-use CSV table with a header row:

Each record becomes one row.
Each field becomes one column.
Commas, quotes, and newlines inside values are escaped per standard CSV rules.
Nested messages and arrays appear as compact JSON text in their cell.
Missing fields become empty cells instead of shifting columns.

When this helps

You have a dump of protobuf messages and want to open it in a spreadsheet
You need to feed protobuf records into analytics or a database import
You want a quick text preview of a record-oriented protobuf dataset