TrueTool
📦 Parquet, CSV & JSON Viewer & Converter
🔒 No Signup · No Upload · 100% Local Processing
Open, inspect, query and convert .parquet, .csv and .json files with this free online Parquet viewer — everything runs right in your browser. Powered by DuckDB compiled to WebAssembly, so you can view a 100 MB analytical file, and even run SQL against it, without installing Python, Spark or Java. Your data never leaves your device.
Click to upload or drag & drop a file here
Supports .parquet, .csv, .tsv, .json, .jsonl, .ndjson — parsed locally, never uploaded.
What Is a Parquet File?
Parquet is a columnar storage format designed for large analytical datasets. Instead of storing rows one after another (like CSV), it stores each column separately and compresses it. That makes Parquet files dramatically smaller than CSV and much faster to query — which is why it is the default format for DuckDB, Apache Spark, pandas and Apache Arrow, and a first-class citizen in data warehouses and data lakes.
The trade-off is that Parquet is not human-readable: you can't open it in a text editor the way you can a CSV. That's what this page is for — it lets you open, read and view Parquet files online, right in your browser, and shows the metadata and rows as a normal table, with export options to get back to CSV, JSON or Excel. The same viewer also opens CSV and JSON files, so it works as a general-purpose file explorer for tabular data.
What Is a CSV File?
A CSV (comma-separated values) file is a plain-text table where each line is one row and columns are separated by commas. It is the most widely supported data format — Excel, Google Sheets, databases and analytics tools all read and write it — but it carries no type information and is not compressed, so very large CSVs become slow to open in a spreadsheet.
This CSV viewer opens .csv and .tsv files directly in your browser. It auto-detects the delimiter and header row, shows the data as a sortable, filterable table, and exports it back to CSV, JSON or Excel in one click.
What Is a JSON File?
JSON (JavaScript Object Notation) is the standard format for exchanging data over the web — it is what most APIs return. A JSON file is usually an array of objects, or a newline-delimited stream of objects (.jsonl / .ndjson), and it is not meant to be read by hand.
This JSON viewer opens .json, .jsonl and .ndjson files, automatically detects whether they contain an array or newline-delimited records, and displays them as a normal table. You can query them with SQL or export them to CSV, JSON or Excel.
How to Use
- Upload or paste a URL — drop a
.parquet,.csvor.jsonfile into the zone, click to browse, or paste a public URL (GitHub raw, S3, etc.). - Browse the data — the tool shows the schema (columns + types), the row count and the detected format, then renders the rows in a table. Click a column header to sort, use the search box to filter, and paginate through the results.
- Run SQL (optional) — switch to the SQL tab and query the file as a table named
data. - Export — download the (optionally filtered and sorted) result as CSV, JSON or XLSX in one click.
How to Convert Parquet to CSV, JSON or Excel
This free online Parquet converter works in three steps: load the file (upload it or paste a URL), optionally filter and sort the rows, then click one of the Export buttons. CSV and JSON exports are streamed straight from DuckDB, so they stay fast even on 100 MB files; XLSX (Excel) is generated locally for opening in a spreadsheet.
- Parquet to CSV — click Export CSV for a comma-separated file that opens in Excel or Google Sheets.
- Parquet to Excel (XLSX) — click Export XLSX for a native spreadsheet, with numeric and boolean columns kept as real cells.
- Parquet to JSON — click Export JSON for an array of objects, or run a custom query in the SQL tab and export that result instead.
- CSV / JSON to CSV / JSON / Excel — the same buttons work for CSV and JSON files, so the page doubles as a CSV-to-JSON or JSON-to-CSV converter.
Everything runs locally in your browser — the file is never uploaded, and no signup is required.
Features
- Multiple formats — Parquet (
.parquet), CSV (.csv,.tsv) and JSON (.json,.jsonl,.ndjson), auto-detected. - 100% local & private — DuckDB-WASM parses and queries the file in your browser; nothing is uploaded.
- All Parquet compression codecs — snappy, gzip, zstd and lz4 all load correctly.
- Interactive table — column sorting, full-text filtering and pagination for large files.
- Built-in SQL — query the file with DuckDB SQL, run multiple statements, and inspect the schema.
- One-click export — CSV, JSON and Excel (XLSX) for both the main table and every SQL result.
Frequently Asked Questions
What is a Parquet file?
Parquet is a columnar file format used for large analytical datasets. It compresses data column-by-column, which makes it small on disk and fast to query, and it is the default storage format in tools like DuckDB, Spark, pandas and Arrow.
Is there a free online Parquet viewer?
Yes — this page is one. It opens Parquet files entirely in your browser: no signup, no installation, and no upload. Drop a file in to view the rows, check the schema, run SQL, and export the result.
What file formats can I open?
This viewer reads Parquet (.parquet), CSV (.csv, .tsv) and JSON (.json, .jsonl, .ndjson) files. The format is detected automatically from the file extension or its content.
How do I read a Snappy-compressed Parquet file?
Open it like any other Parquet file. Snappy, gzip, zstd and lz4 compression are all decompressed automatically in your browser — there is nothing to install and no separate conversion step.
How do I open a Parquet, CSV or JSON file online without installing Python or Spark?
Open this page and drop your file into the upload zone. It is parsed locally in your browser with DuckDB compiled to WebAssembly, so you don't need Python, Spark, Java or any other tool installed.
Can I run SQL queries against my file?
Yes. The loaded file is available as a table named data in the SQL tab. You can filter, aggregate and join it with regular DuckDB SQL — all executed locally in your browser.
Can I view Parquet schema and metadata online?
Yes. As soon as a file loads, the viewer shows the detected format, the row count and the column schema — every column name and its type. All of it is read from the file itself, locally in your browser.
Is my data uploaded to a server?
No. The file is read and queried entirely inside your browser. Your data never leaves your device and is never sent to any server.
How do I convert Parquet, CSV or JSON to CSV, JSON or Excel?
Load your file, then use the Export buttons to download it as CSV, JSON or XLSX (Excel). The conversion runs locally in your browser — no upload and no server round-trip.
What is the maximum file size I can open?
There is no hard limit — the tool reads files directly in your browser's memory, so the practical limit is your device's available RAM and browser. Files of 100 MB and more typically load fine on a modern machine.