Data Visualizer
Upload CSV, JSON, or Parquet files and build interactive charts instantly. Bar, line, area, pie, and scatter — with aggregations, top-N filtering, and multi-dataset support.
100% In-Browser Processing. Your files never leave your device.
Build charts from your data
Drop one or more data files to instantly create bar, line, area, pie, and scatter charts.
or drag & drop files here · Multiple files supported
What is Data Visualizer?
The Data Visualizer is a browser-based business intelligence (BI) tool that lets you load data files and immediately build charts without any server, database, or BI platform required. It supports CSV, JSON, and Parquet files — the most common formats in data engineering, analytics, and reporting workflows. You can load multiple files simultaneously, switch between datasets, and build multiple charts on the same dashboard.
How to Use Data Visualizer
- Drop one or more CSV, JSON, or Parquet files onto the upload zone, or click "Browse files" to select them.
- The dataset bar at the top shows all loaded files with their row counts. Click a tab to make it the active dataset for the Data Preview.
- In the Chart Builder panel, select a chart type: Bar, Line, Area, Pie, or Scatter.
- Choose the X axis field (the category or dimension to group by) and the Y axis field (the value to measure).
- Select an aggregation: Count, Sum, Average, Min, or Max. Use "Top N" to limit how many groups are shown.
- Optionally enter a custom chart title, then click "Add Chart" to add it to the dashboard.
- Switch to the "Data Preview" tab at any time to inspect the raw rows of the active dataset.
Common Use Cases
- Quickly visualising a CSV export from a database to spot trends before importing into a BI tool.
- Checking data quality in a Parquet file by plotting value distributions as a bar chart.
- Comparing sales by region or category from a spreadsheet export without needing Excel.
- Exploring a JSON API response or log export to understand frequency distributions.
- Building ad-hoc charts from multiple datasets side-by-side during data analysis.
Why Use an In-Browser Tool?
All data processing and chart rendering happens entirely in your browser. Your files — which may contain sensitive business data, customer records, or financial metrics — are never uploaded to any server. The tool uses JavaScript to parse files and Recharts to render visualisations locally on your device.
Frequently Asked Questions
What file formats are supported?
CSV, JSON (array of objects or columnar format), and Parquet. JSON arrays are automatically flattened up to 3 levels deep. For very large files, parsing may take a few seconds — everything runs in your browser tab.
Can I load multiple files at once?
Yes — drop or select multiple files at once. Each file becomes a separate dataset tab. You can switch between them in the dataset bar and build charts from any dataset in the builder.
What does the aggregation setting do?
For bar, line, area, and pie charts, the tool groups rows by the X axis field and computes an aggregate value for each group. Count returns the number of rows per group. Sum, Average, Min, and Max operate on the numeric values in the Y axis field.
Why is my chart showing unexpected results?
Check the detected column types shown in the column dropdowns. If a numeric column is detected as "string" (common with formatted numbers like "1,234"), the aggregation may not work as expected. For best results, use clean numeric values without formatting in the Y axis column.