Developer Tools

Free, privacy‑friendly utilities for engineers and analysts. Convert data formats, validate payloads, and speed up daily tasks — all running locally in your browser so your data never leaves your device.

Open ConverterJSON ↔ YAML ↔ XML ↔ CSV ↔ Excel
18 / 18 tools
  • Universal Converter

    Convert JSON ↔ YAML ↔ XML ↔ CSV ↔ Excel in your browser.

  • Case Converter

    Convert text between camelCase, PascalCase, snake_case, SCREAMING_SNAKE_CASE, kebab-case, Title Case, and sentence case.

  • Meta Tag Generator

    Generate SEO meta tags, Open Graph, and Twitter cards with live previews and copy/download.

  • Sitemap Generator

    Create valid XML sitemaps by crawling a site or pasting URLs, with changefreq, priority, and lastmod options.

  • Robots.txt Generator

    Generate robots.txt with allow/disallow rules, user-agents, crawl-delay, and sitemap.

  • CSV to JSON Converter

    Convert CSV files to JSON in your browser with upload, copy and download.

  • JSON to CSV Converter

    Convert JSON arrays into CSV in your browser with upload, copy and download.

  • CSV to Excel Converter

    Convert CSV to Excel (.xlsx) instantly and download the file.

  • CSV Merge Tool

    Upload multiple CSV files and merge them into one download.

  • CSV Splitter

    Split a large CSV into multiple files by row count.

  • CSV Duplicate Remover

    Remove duplicate rows by entire row or a specific column.

  • JSON Formatter & Validator

    Format, validate, and minify JSON with a raw and tree view.

  • CSV Validator

    Validate CSV files for malformed rows, duplicate headers, and delimiter issues.

  • CSV to Chart Visualizer

    Render bar, line, or pie charts from CSV data.

  • CSV Cleaner

    Fix BOMs, normalize quotes, trim fields, and standardize delimiters.

  • Base64 Encoder / Decoder

    Encode/decode text, files, and images to/from Base64 with copy/download and image preview.

  • JWT Decoder

    Decode JWT header, payload, and signature fully client-side, with formatted JSON and copy/download.

  • Keyword Density Checker

    Analyze keyword frequency and density from text; copy or download CSV/Excel.

Frequently Asked Questions

Do these tools send my data to a server?

No. Everything runs in your browser using Web APIs and open‑source libraries. Nothing is uploaded.

Can I convert Excel files with multiple sheets?

Currently the first sheet is used. Multi‑sheet selection is planned.

Is this suitable for large files?

Yes within browser memory limits. For very large datasets we recommend chunking.