Data Visualization Toolkit

BY TOOLS.FUN  ·  MARCH 28, 2026  ·  5 min read

Data visualization professionals transform raw numbers into compelling visual stories. Whether you are building dashboards in Tableau, creating D3.js visualizations, or designing reports in Looker, you constantly need to convert colors, format data, and prepare assets. These free, browser-based tools handle the supporting tasks so you can focus on making data beautiful and understandable.

Color Converter

Convert colors between HEX, RGB, HSL, and other formats instantly. Match brand guidelines to chart palettes, translate Figma design tokens to D3.js color scales, and verify accessibility contrast ratios.

Best for: building custom chart color palettes, translating brand colors to code, verifying WCAG contrast ratios for accessible charts.

JSON Formatter & Validator

Pretty-print JSON data feeds that power your visualizations. Validate the structure of API responses, Vega-Lite specs, and D3.js data files before rendering. The formatted view reveals data shape issues that break charts.

Code to Image

Turn D3.js, Python, or R visualization code into clean, shareable images for presentations, blog posts, and documentation. Syntax-highlighted snippets look professional in slide decks.

JSON to YAML Converter

Convert JSON chart configurations to YAML for dashboard-as-code workflows, Grafana provisioning, and CI/CD-managed visualization deployments.

Code Diff Tool

Compare chart configurations, dashboard exports, and visualization code before and after changes. Essential for reviewing updates to shared dashboards and catching unintended modifications.

Best for: reviewing Grafana dashboard JSON changes, comparing Tableau workbook exports, tracking D3.js code modifications.

RegExp Tester

Build regex patterns for data label formatting, axis tick customization, and text extraction from datasets. Test patterns before embedding them in visualization code.

JS Beautifier

Unminify D3.js code, Observable notebooks, or embedded chart scripts. When you inherit someone else's visualization code, this tool makes it readable again in seconds.

Timestamp Converter

Convert Unix epoch timestamps to human-readable dates for time-series chart axis labels. Debug timezone issues in temporal visualizations across different locales.

Base64 Encoder / Decoder

Encode images as Base64 for embedding in SVG visualizations, data URIs in CSS backgrounds, or inline chart assets. Decode Base64-encoded data from APIs before visualization.

QR Code Generator

Generate QR codes linking to interactive dashboards, published reports, or data portals. Perfect for printed reports, conference posters, and executive summaries that link to live data.

Character Counter

Check label lengths for chart axes, legend entries, and tooltip text. Ensure text fits within the visual space constraints of your chart layout.

Duplicate Line Remover

Clean up data labels, category lists, and dimension values before feeding them into visualizations. Duplicate entries create confusing chart legends and incorrect aggregations.

Best for: cleaning dimension values before charting, deduplicating exported category lists, preparing legend entries.
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