Debug an API response
Paste the raw JSON to format and validate it. If the response contains Base64-encoded fields, decode them. If query parameters look wrong, use the URL parser to inspect them.
Free Developer Tools – JSON Formatter, Base64, URL Encoder, Password Generator & More
Format code, encode data, generate passwords, and solve small developer tasks from the browser.
Developer tools on ToolMint are built for the small, immediate tasks that come up during development, testing, debugging, and support: formatting a JSON payload, encoding a URL parameter, decoding a Base64 string from an API response, generating a secure password for a new service, or testing a front-end snippet without spinning up a project. Each tool runs entirely in the browser — nothing is sent to any server.
The tools here are useful not just for engineers but for QA analysts, support agents, SEO specialists, and students who need a quick technical utility without installing anything.
JSON Formatter
Beautify, validate, minify, and convert JSON to XML, CSV, or YAML — with inline error location on parse failure.
Code Snippet Playground
Write HTML, CSS, and JavaScript in split editors with a sandboxed live preview that updates as you type.
Python Code Editor
Run Python code directly in your browser using Pyodide (WebAssembly CPython) — no install, stdin simulation included.
Base64 Encoder/Decoder
Encode text or files (images, PDFs, binary) to Base64 and decode Base64 strings back to plain text — UTF-8 safe.
URL Encoder/Decoder
Encode URLs with 4 percent-encoding methods, decode with 3 methods, and parse any URL into its components.
Password Generator
Generate cryptographically secure passwords (up to 128 chars) or passphrases with entropy score using Web Crypto API.
Popular Workflow Paths
Set up a new project or account
Generate a strong password for the new service, then use the JSON formatter to clean up any config files you copy in.
Learn or prototype without setup
Write and run Python directly in the browser for quick experiments, or use the HTML/CSS/JS playground to prototype a UI component without creating a project.
What You Can Do In This Category
JSON Workspace
Beautify, validate, minify, and convert JSON to XML, CSV, or YAML — with exact line-number error location on parse failure.
Encoding Utilities
Handle Base64 encoding/decoding for text and files, and URL percent-encoding with the correct method for query params vs full URLs.
Code Playgrounds
Live HTML/CSS/JS preview with sandboxed iframe isolation, and a full Python environment powered by Pyodide WebAssembly — no install needed.
Security Tools
Generate cryptographically secure passwords and passphrases using the Web Crypto API with entropy scoring in bits.
Frequently Asked Questions
- Why use browser-based developer tools instead of local scripts?
- For small immediate tasks — formatting one JSON response, decoding one Base64 string — opening a browser tab is faster than switching to a terminal, writing a script, and running it. These tools are optimized for that use case: paste input, get output, move on.
- Are these tools safe to use with sensitive data?
- Yes. All processing runs in your browser. No JSON, Base64, URL, or password data is ever sent to any server. Your data stays on your device.
- Who else besides developers uses these tools?
- QA testers debugging API responses, support engineers reading encoded tokens, SEO specialists parsing URLs, students learning to code, and anyone who needs a quick encoding or formatting task done without installing a tool.