Development Tools
Development tools for the small utilities that show up on every engineer's desktop and never feel important enough to install an app for: a strong password generator, a JSON validator and formatter with sane error messages, a JSON schema stripper for trimming a schema down to fit a model context window, a tokenizer for cost-estimating LLM prompts, a screen resolution simulator, a What-Is-My-IP analyzer, and a prompt chain tool for building multi-step model interactions. Everything runs client-side so the values you paste are not transmitted, which is the right answer for anything that contains keys, tokens, internal endpoints, or proprietary prompts. The common mistake when working with model context windows is counting words instead of tokens; the ratio differs by language and prompt style, and a long technical document can use 30 to 50 percent more tokens than its word count suggests, which is why the token tools here report per-model counts rather than a single average. If you are new to the category, start with the JSON validators for any malformed payload you need to debug, the credential generators for any new secret, and the token counters before sending a prompt that approaches a model's context limit. The prompt tools are the right place to start when you are decomposing a single large prompt into a more reliable multi-step sequence.
33 tools available
BBCode to HTML Converter
Convert BBCode markup to clean HTML output or reverse the process by transforming HTML back into BBCode.
Basic Color Contrast and Font Size Legibility Checker
Evaluate foreground and background color pairs against WCAG 2.
Basic Formatting to Raw HTML Converter
Convert bold, italic, heading, link, and list patterns from plain or Markdown-style text into clean, semantic HTML markup.
Credit Card Generator
Luhn-valid test card numbers built from real IIN prefixes and lengths for Visa, Mastercard, American Express, Discover, JCB, Diners Club, and UnionPay.
Extract Text From Tool
Strip markup and data formatting from HTML, BBCode, JSON, CSV, XML, Markdown, and YAML to produce clean plain text with character, word...
HTML to PHP Converter
Convert raw HTML markup into PHP echo, print, heredoc, or concatenation statements with configurable quote styles and variable names.
HTML to YAML Converter
Convert HTML markup into structured YAML output by parsing elements, attributes, and text nodes into a hierarchical key-value representation.
JSON Converter
Convert structured data between JSON, TSV, and XML formats with automatic type detection and bidirectional transformation.
JSON Schema Stripper
Walks a JSON tree and drops null, empty-string, empty-array, or empty-object leaves under independent toggles.
JSON Validator and Formatter
Validates JSON and either pretty-prints with two-space indentation or compresses to a single line.
JSON Viewer
Parse, format, and explore JSON data through a collapsible tree view with expand and collapse controls at every nesting level.
JSON to One Line Formatter
Condense multi-line JSON into a single compact line by stripping whitespace, newlines, and indentation while preserving structure.
JSONPath Tester
Evaluate JSONPath expressions against any JSON document and inspect every matching node alongside its full path in the data tree.
Java Viewer
Paste Java source code and view it with syntax highlighting, line numbering, and code statistics such as comment density.
JavaScript Tester
Run JavaScript code snippets directly in the browser and capture console output, return values, and runtime errors without any server or build...
Javascript Obfuscator
Obfuscate JavaScript by renaming variables, encoding strings as hex escape sequences, and replacing numeric constants with arithmetic expressions.
Markdown Table Generator
Build pipe-delimited markdown tables by entering headers, choosing per-column alignment, and filling data rows through an interactive grid.
OPML to JSON Converter
Convert OPML outline documents into structured JSON, preserving attributes, nested hierarchies, and head metadata from version 1.
PHP Formatter
Format and beautify raw or minified PHP code with configurable indentation depth, brace placement style, and operator spacing rules applied in a...
Password Generator
Random password generator with selectable length (4 to 128 characters) and character classes (upper, lower, digits, symbols, or a custom set).
Prompt Chain Tool
Build and manage AI prompts visually by structuring reusable phrase pills with drag-and-drop editing, validation, and export features to improve productivity and...
Regex Tester
Test and debug regular expressions against a test string, listing each match with its index, capture groups, and an optional replacement preview.
Ruby Formatter Beautifier
Format and beautify raw or minified Ruby code with configurable indentation depth, blank-line handling, and operator spacing applied in a single pass.
SHA Hash Generator
Generate SHA hashes from text input across 13 algorithms in the SHA-1, SHA-2, and SHA-3 families.
Sass Converter
Convert stylesheet code between SCSS, Less, Sass (indented syntax), and Stylus formats with a bidirectional swap for round-trip verification.
Screen Resolution Simulator
Reports the browser's screen size, viewport size, device pixel ratio, and color depth on load and on every resize.
Secrets Redactor
Scan and redact API keys, tokens, passwords, private keys, and other credentials from pasted text before sharing code snippets or providing context...
Structured Text to Markdown Converter
This tool formats basic structured text blocks from a Word document into clean, consistent Markdown based on a predefined schema.
Text From Regex Generator
Generate random strings that match a regular expression, with support for character classes, quantifiers, alternation, groups, and anchors.
Text Skip-Grams Generator
Extract skip-grams from any text by specifying the n-gram size and maximum skip distance between selected tokens.
Token Calculator
Counts tokens in pasted text with OpenAI's o200k_base byte-pair tokenizer, exact for GPT-4o and newer and approximate for other providers.
UUID Generator
Generate universally unique identifiers (UUIDs) in v1, v4, and v7 formats with batch output up to 1000 at a time.
XML Formatter
Format and beautify raw XML with customizable indentation levels from 1 to 16 spaces and optional alphabetical attribute sorting.