Common use cases
- Convert a CSV export to JSON
- Format and validate JSON payloads
- Test a regular expression against sample text
- Preview README markdown before publishing
CSV ⇄ JSON Converter
Convert CSV and JSON locally in your browser with paste, preview, copy and download — no uploads.
JSON Formatter
Format, validate, and inspect JSON for APIs, web apps, and debugging.
URL Encoder / Decoder
Encode or decode URLs and query-string values using encodeURIComponent or encodeURI. Instantly shows both encoded and decoded output.
URL Parameter Builder
Build, edit, and clean URL query parameters. Add UTM tracking, strip tracking params, and preview the before/after URL.
Regex Tester
Write a regular expression and see live match highlighting with match count, index positions, and capture groups.
Text Diff
Paste two blocks of text to see what changed — added lines highlighted green, removed lines in red.
File Viewer
Drop any file to view it: images, audio, video, PDF, text, code, JSON, CSV, HTML — or a hex dump for binary files. Edit text and download.
Meta Tag Previewer
Create, preview and copy SEO, Open Graph and Twitter meta tags locally in your browser — no uploads.
Markdown Previewer
Write Markdown and preview formatted output instantly in your browser without uploads.
Frequently asked questions
Can I paste production data into these tools?
These tools run locally, but avoid pasting secrets, credentials, or personal data into any online utility — including this one.