Free online developer tools

Escapes or unescapes special characters in JSON strings in the browser.

Points at a remote MCP endpoint to browse the capabilities it exposes and try calling one with your own arguments.

Beautifies XML and flags syntax errors immediately, processing the text locally.

Checks XML for malformed tags, nesting and attribute errors and reports document statistics locally.

Vector search over documents using a Postgres running in WebAssembly (PGlite) inside the browser.

Crunches 50,000 log lines either on the main thread or in a Web Worker, so you can feel the difference in UI blocking.

Renders exported Claude widgets and artifacts offline with the missing theme styles restored, and stores them in the browser.

Side-by-side comparison and merging of text, code, Word, PowerPoint and PDF files, running offline, with extra text clean-up commands.

Runs Python in the browser through Pyodide WebAssembly, with a code editor, .py load and save, and micropip packages.

A click-to-edit visual editor for HTML pages made by AI tools, with text, color and font changes and clean HTML export.

Escapes quotes and special characters so JSON can sit safely inside a string.

Compares two JSON documents and shows how they differ.

Strips whitespace from JSON to shrink it.

Picks random network port numbers for local development.

Sorts the keys of a JSON object alphabetically.

Turns JSON into a single quoted string value.

Runs prompts against the language model built into Chrome, downloading it on first use.

Boots a small Linux image through the v86 x86 emulator so you can run shell commands in a tab.

Lets you pick a local folder and browse and search its file tree in the browser.

Renders Mermaid flowcharts and sequence diagrams as Unicode box-drawing text using a WebAssembly library.

Renders Mermaid flowchart and sequence diagrams as terminal-style Unicode box art in the browser.

Runs MicroPython in WebAssembly and stores the code in the URL so snippets are easy to share.

Executes ES5-style JavaScript in a small WebAssembly engine and keeps the code in the page address.

Removes comments from Python code using the real tokenizer on Pyodide, leaving strings and docstrings intact.