Developer Tools
Free Online Utilities for Developers
The Stack Overflow 2023 Developer Survey found that 78% of developers use online tools for encoding, decoding, and formatting tasks that do not warrant installing a dedicated application. Format a JSON payload, encode credentials for an Authorization header, generate a batch of UUIDs for a test database, decode a URL query string from a server log, convert a Unix timestamp to a readable date — this collection covers all of it. Everything runs in your browser using standard JavaScript APIs. No installation, no npm package, no Docker container. Your data never touches a server during any operation.
All Developer Tools
Unminify and format minified HTML code for better readability
Unminify and format minified CSS code for better readability
Unminify and format minified JavaScript code for better readability
Format and prettify JSON with 2 or 4-space indentation. RFC 8259 compliant, 100% browser-based
Validate JSON syntax against RFC 8259. Get precise error messages with line and column numbers
Minify JSON by removing all whitespace. Reduce payload size by 30-50% for faster API responses
Encode text to Base64 (RFC 4648). Supports UTF-8 and URL-safe mode. No data uploaded
Decode Base64 strings to plain text. Inspect JWTs, data URIs, and API payloads privately
Percent-encode URLs and URI components per RFC 3986. Handles Unicode and special characters
Decode percent-encoded URLs back to readable text. Debug redirects and query parameters
Generate cryptographically random UUID v4 identifiers (RFC 9562). Bulk generation supported
Generate strong passwords using Web Crypto API. Configurable length, charset, and complexity
Convert Unix timestamps to ISO 8601 dates and back. Supports seconds and milliseconds
Generate QR codes from text or URLs. Customize size, format (PNG/SVG), and error correction level
Generate placeholder Lorem Ipsum text. Choose paragraphs, sentences, or words with custom count
Compare two texts and highlight differences line by line. Unified diff output with context lines
Generate SHA-1, SHA-256, SHA-384, SHA-512 hashes. Output in hex or Base64 format
Minify CSS code by removing whitespace, comments, and redundant rules. See compression stats
Minify HTML by collapsing whitespace, removing comments and redundant attributes
Minify JavaScript code with compression and variable mangling. Powered by Terser
Convert JSON arrays to CSV format. Configure delimiter and header options
Convert CSV data to JSON format. Auto-detect headers and delimiters
Convert YAML to JSON format. Handles nested structures and arrays
Convert JSON to YAML format. Configurable indentation
Convert XML to JSON format. Optional attribute parsing
Convert JSON to XML format. Pretty print with customizable output
Format and indent XML for readability. Configurable indentation
Convert Markdown to HTML. Supports headings, lists, code blocks, and links
Convert HTML to clean Markdown. ATX headings and fenced code blocks
Encode or decode HTML entities. Named references like & <
Test regular expressions with match, replace, and split modes. Real-time results with capture groups
Decode JWT tokens to inspect header, payload, and signature. View claims and expiration
Build cron expressions with an interactive form. Human-readable descriptions included
Format and beautify SQL queries. Supports MySQL, PostgreSQL, SQLite, T-SQL dialects
Convert images to Base64 data URLs. Get HTML img tag and CSS background snippets
Transform text into ASCII art with multiple font styles. Uses FIGlet fonts
JSON Tools
JSON makes up over 90% of REST API traffic (Postman 2023 State of the API). Three dedicated tools cover the complete JSON workflow. The JSON Formatter beautifies any JSON with 2-space or 4-space indentation using the native JSON.stringify engine — paste a minified API response and read it in seconds. The JSON Validator checks RFC 8259 compliance and reports errors with exact line and column numbers, catching the trailing commas, single-quoted strings, and missing colons that account for roughly 15% of API debugging time. The JSON Minifier strips all whitespace to reduce payload size by 30-50%, cutting bandwidth and storage overhead in production. Use the Validator first, then Formatter for development, then Minifier for production deployment.
Encoding and Decoding
The Base64 Encoder and Base64 Decoder handle HTTP Basic Auth encoding, JWT payload inspection, data URI generation, and MIME attachment processing. Both support standard Base64 (RFC 4648 §4) and URL-safe Base64 (RFC 4648 §5) used in JWTs and OAuth tokens. Base64 adds exactly 33% overhead — 3 input bytes become 4 output characters — a trade-off that exists because binary data needs to survive text-only channels. The URL Encoder and URL Decoder apply RFC 3986 percent-encoding for query strings, redirect URL construction, and server log analysis. Both tools support encodeURI mode (preserve URL structure) and encodeURIComponent mode (encode individual parameter values). Never double-encode — if a value already contains %20, encoding it again produces %2520.
Generation and Conversion
The UUID Generator creates cryptographically random v4 UUIDs in bulk using crypto.randomUUID(), producing identifiers with 5.3×1036 possible values per RFC 9562. The Password Generator produces configurable passwords using crypto.getRandomValues() per NIST SP 800-63B — a 16-character password with the full 94-character set has ~105 bits of entropy. The Timestamp Converter translates Unix timestamps (seconds and milliseconds) to ISO 8601 dates and back, supporting both UTC and local time zones. ISO 8601 is the recommended format for API responses and database storage because it is unambiguous and lexicographically sortable. These three tools cover the most common generation and conversion tasks in daily development workflows.
Privacy by Design
All tools process data entirely in the browser. API keys, JWT tokens, database credentials, password hashes, and any other sensitive data you paste into these tools never reach any server. There are no server-side API endpoints, no proxies, and no analytics capturing input values. Open your browser's Developer Tools Network tab while using any tool and you will see zero outbound requests during processing. This makes the tools safe for use in environments with strict data handling requirements.
Frequently Asked Questions
Do I need to install anything to use these developer tools?
No. All tools run directly in your browser using standard JavaScript APIs: JSON.parse, btoa/atob, encodeURIComponent, crypto.randomUUID, Date. Any modern browser — Chrome 90+, Firefox 88+, Safari 15+, Edge 90+ — on desktop or mobile works correctly.
Why are there no login requirements or API rate limits?
All tools run client-side, consuming no server compute resources. There is nothing to rate-limit, no database queries to throttle, and no compute costs to recover. Format thousands of JSON payloads or generate millions of UUIDs without any restrictions.
Are these tools accurate enough for production debugging?
Yes. Each tool uses the browser's native, production-grade JavaScript APIs. JSON tools use JSON.parse and JSON.stringify — the same engine used in Node.js. UUID generation uses crypto.randomUUID(), a W3C Web Cryptography API standard. Timestamp conversion uses the browser's Date object. These are the same APIs you use in production code.
Can I share a link to a specific tool pre-filled with my data?
Individual tools may support URL query parameters for pre-filling input values, enabling shareable links for specific conversions or examples. Because all processing is client-side, sharing a link is safe — the input data in the URL is processed only in the recipient's browser, not on any server.
How do I report a bug or suggest a new developer tool?
Use the feedback link in the page footer to report incorrect output, unexpected behavior, or to suggest new tools. When reporting a bug, include the specific input that produced incorrect output so it can be reproduced and fixed.