Developer Tools
32 free online tools
About Developer Tools
Developers spend a surprising amount of time on small data chores — pretty-printing a JSON blob, decoding a token, testing a regex, encoding a string, formatting a query. ToolForge gathers those utilities in one place: format and validate JSON and explore it by path, encode and decode Base64 and URLs, test and explain regular expressions, generate UUIDs, decode JWTs, format SQL, convert and diff text, minify code, and more.
Crucially, these all run client-side in your browser, so the code, tokens, and API payloads you paste never travel to a server — a real concern when you are debugging with production data. There is no sign-up and no rate limit, so they fit naturally into a debugging session whether you are building an API, integrating a third-party service, or just trying to read a minified response.
Popular Developer Tools
Related Categories
JSON Formatter
Format, validate, and beautify JSON online
Base64 Encoder / Decoder
Encode and decode text, files, and images to Base64
URL Encoder / Decoder
Encode and decode URL strings
JSON to CSV Converter
Convert JSON data to CSV format
JSON Diff Comparator
Compare two JSON files and find differences
JSON Path Finder
Find and extract values from JSON using JSONPath
JSON Escape / Unescape
Escape and unescape JSON strings
JSON Stringify Tool
Convert JavaScript objects to JSON strings
JSON Parse Tool
Parse JSON strings into JavaScript objects
JSON Filter Tool
Filter JSON data by keys and values
JSON Schema Visualizer
Visualize JSON Schema structure and validation
Regex Tester
Test regular expressions with real-time matching
Regex Explainer
Explain regular expressions in plain English
UUID Generator
Generate UUID v4 and other UUID versions
JWT Decoder
Decode and verify JSON Web Tokens
String Converter
Convert between string formats (camelCase, snake_case, etc.)
SQL Formatter
Format and beautify SQL queries
Markdown to HTML
Convert Markdown to HTML
Text Diff Checker
Compare two text blocks and find differences
HTML Viewer & Live Preview
View and preview HTML code in real time
Code Minifier
Minify JavaScript, CSS, and HTML code
Cron Expression Builder
Build and test cron expressions visually
CSS Grid Generator
Generate CSS Grid layouts visually
HAR Viewer
View and analyze HTTP Archive (HAR) files
Unix Timestamp Converter
Convert epoch timestamps to dates and back in real time
CSV to JSON Converter
Convert CSV data to JSON arrays instantly in your browser
XML to JSON Converter
Parse XML strings to clean JSON objects in your browser
YAML ↔ JSON Converter
Bidirectional YAML and JSON conversion with error reporting
HTML Entity Encoder / Decoder
Encode and decode HTML entities and special characters
CSV Diff Viewer
Compare two CSV files and highlight row and cell differences
ROT13 / Caesar Cipher
Encode and decode ROT13 and any Caesar cipher shift 1–25
Security Header Analyzer
Analyze HTTP security headers
Frequently Asked Questions
Is it safe to paste sensitive data like tokens into these tools?
These developer tools process everything locally in your browser, so the data you paste is not uploaded. That said, on a shared or untrusted computer, treat any secret with caution as a general practice, and remember that decoding a token does not make it less valid.
Why is my JSON showing as invalid?
The usual culprits are trailing commas, single quotes instead of double quotes, unquoted keys, or an unclosed bracket — JSON is stricter than JavaScript object syntax. The JSON formatter and parser report the exact error so you can find and fix it.
Do these tools work without an internet connection or account?
No account is ever required, and because the logic runs in your browser, most will keep working even offline once the page has loaded. A few — such as DNS or header lookups in the network section — do call external services, but the core developer utilities are fully local.
Which JSON tool should I use?
Use the formatter to pretty-print and validate, the parser to clean a minified string, the path finder to extract a specific value, the filter to narrow an array, and the diff to compare two documents. Each focuses on one job so the right tool is quick to reach for.
