Essential Developer Utilities
JSON formatting, JWT inspection, regex testing, UUID, hash, and timestamp conversion. Pages labelled local processing keep pasted text in the tab.
All Developer Tools
Formatters and testers with documented limits. JWT decoding is not verification.
Code to Image
Create beautiful code screenshots.
cURL Converter
Convert cURL commands into Fetch, Axios, and Python snippets.
GitHub Graph Simulator
Visualize merge, rebase, and git flow.
Hash Generator
Generate SHA hashes for text or files using Web Crypto APIs.
JSON Diff Checker
Compare two JSON payloads and inspect exact field-level changes.
JSON Formatter
Formats, validates, and minifies JSON, and can emit YAML or TypeScript.
JWT Decoder
Decode, verify and inspect JSON Web Tokens securely.
Open Graph Preview
Preview pages on social media.
Password Generator
Builds a password with Math.random from the selected sets. The default length is 16.
RegExp Tester
Test and debug Regular Expressions with live highlighting.
Schema Markup Generator
Builds FAQ, HowTo, or Product JSON-LD. A schema.org validator is not run.
SQL Formatter
Beautify and debug SQL queries.
SQL Query Generator
Visually build SQL queries.
Timestamp Converter
Convert Unix seconds, milliseconds, and date strings instantly.
UTM Builder
Adds utm_source, utm_medium, and utm_campaign to an absolute URL with URLSearchParams. Term and content are optional.
YAML ↔ JSON
Converts YAML to JSON with yaml.load, or JSON to YAML with yaml.dump. A parse error is shown.
Barcode Generator
Create custom barcodes (EAN, UPC, etc).
Base64 Converter
Encode and decode strings to and from Base64 format.
Bcrypt Generator
Generate and verify Bcrypt password hashes securely.
chmod Calculator
Turns read, write, and execute checkboxes into a 3-digit octal mode and an rwx string. The command has no filename.
Cron Generator
Generate, parse and explain cron expression schedules.
CSS Minifier
Compress CSS to reduce file size.
CSV ↔ JSON
Converts a headered CSV to JSON objects, or an array of objects to CSV. Cell values stay strings.
CSV to KML
Converts tabular spreadsheet coordinates (latitude, longitude, name) into Google Earth KML placemarks.
CSV to Markdown
Converts CSV or tab-separated data into aligned GitHub-flavored Markdown tables. Kept 100% in your browser.
Diff Checker
Compare two texts and find differences.
GeoJSON to KML
Converts GeoJSON features (Points, LineStrings, Polygons) to Google Earth KML placemarks client-side.
GPX ↔ KML
Converts GPS tracks and waypoints between GPX and Google Earth KML format with zero server uploads.
Hreflang Generator
Writes one alternate link tag per language and URL pair. It does not add the reverse tags.
HTML Encode / Decode
Encodes &, <, >, and quotes. Decoding also accepts numeric character references. The text stays in the page.
HTML Minifier
Optimize HTML structure.
HTTP Status Lookup
Search common HTTP response codes by number, name, category, or meaning.
JS Minifier
Minify and clean JavaScript code.
JSON Schema Validator
Checks JSON data with AJV against a JSON Schema and lists each error path and message.
JSON to TypeScript
Generates clean TypeScript interfaces and type definitions from JSON data. Processed client-side.
Meta Tag Generator
Creates title, description, and social meta tags for a page.
MIME Type Lookup
Find common MIME media types from a file extension or content type.
NDJSON to CSV
Converts newline-delimited JSON (NDJSON / JSONL) files into clean tabular CSV with automatic header detection.
Robots.txt Generator
Writes a robots.txt with a user-agent, Allow and Disallow lines, and an optional sitemap URL.
Slug Generator
Turn a title into a lowercase hyphenated URL slug, stripping accents and punctuation.
Snowflake Parser
Shifts a Discord snowflake 22 bits and adds the 2015 Discord epoch. The id is not sent to Discord.
SRT ↔ VTT
Converts between SubRip (.srt) and WebVTT (.vtt) caption formats instantly in your browser with zero uploads.
Subtitle Time Shift
Sync out-of-time subtitles by adding or subtracting milliseconds and adjusting frame rates (23.976, 24, 25, 29.97 fps).
Subtitle to Text
Extracts clean dialogue and plain text transcripts from SRT or VTT subtitle files, stripping timestamps and formatting tags.
URL Encoder
Encode and decode URLs or URI components instantly.
UUID Generator
Generate secure v4 UUIDs in bulk effortlessly.
XML Formatter
Formats XML with DOMParser and shows the browser parsererror text when the markup is invalid.
XML to CSV
Flattens XML elements and repeating record trees into tabular CSV format for spreadsheets. 100% private in-browser.
Developer Tutorials & References
How to format JSON and fix parse errors
Trailing commas, quotes, and the first error position the formatter reports.
How to Decode & Inspect JWT Tokens Safely
Decoding is not verification. Read claims, then verify in a trusted environment.
Regex tester notes
JavaScript regex is not PCRE. Flags and backtracking are documented on the tool page.
What these developer tools do
The listed utilities format JSON, decode JWTs, test regular expressions, hash strings, generate UUIDs, and convert timestamps. They are editors and inspectors, not hosted APIs. When a page is labelled local processing, the payload stays in the browser tab. JWT decoding still requires care: a decoded token is not a verified token, and secrets should not be pasted into any web page. The JSON parse guide and JWT inspection guide explain the common failure cases.