All Developer & Code Tools
Tools for developers to test, format, and optimize code.
API Fetch Tester
A simple client to test REST API endpoints.
Chmod Calculator
Calculate file permissions for chmod.
Color Contrast Checker
Check color contrast for WCAG accessibility.
CSS Beautifier
Make your messy CSS readable in seconds.
CSS Gradient Generator
Visually create and customize CSS gradients.
CSS Minifier
Compress CSS code to reduce file size.
HTML Beautifier
Make your messy HTML readable in seconds.
HTML Entity Converter
Convert special characters to HTML entities.
HTML Minifier
Compress HTML code to reduce file size.
JavaScript Beautifier
Clean up messy JavaScript and JSON code effortlessly.
JSON Formatter
Pretty-print and validate JSON.
About Developer & Code Tools
These are the utilities most developers end up Googling individually — a JSON formatter, a CSS minifier, a chmod calculator — collected in one place that loads instantly. Formatting and calculation utilities process input in your browser. API Fetch Tester sends the URL, headers, and body you provide to your chosen endpoint.
Formatting comes in pairs. The CSS beautifier, HTML beautifier and JavaScript beautifier expand compressed source back into something you can read; the CSS minifier and HTML minifier go the other way for production. The JSON formatter validates as well as indents, so an API response that will not parse tells you where it breaks instead of failing silently.
The rest handle the jobs that sit around the code. The API fetch tester fires a request straight from your browser to the endpoint you name — nothing is proxied through ToolsVenue — so you can check a response shape without opening Postman. The HTML entity converter escapes and unescapes markup you need to display rather than render. The chmod calculator turns read/write/execute checkboxes into the octal value you type at a terminal, and back again.
Two are design-side but belong here because they end up in a stylesheet: the colour contrast checker tests a foreground and background pair against the WCAG AA and AAA thresholds before an accessibility audit does it for you, and the CSS gradient generator produces the linear-gradient declaration to paste in.
Further reading: why a JSON formatter belongs in your daily workflow.
Frequently Asked Questions
Does the JSON formatter validate my JSON as well as format it? ▾
Yes. The JSON formatter checks strict JSON syntax and displays the browser parser message when parsing fails; it does not highlight code or check a schema. If your JSON is invalid, the tool shows an error rather than silently producing malformed output.
Is it safe to paste private API keys or code into these tools? ▾
All formatting, minification, and beautification tools run entirely in your browser using JavaScript — nothing is sent to a server. For the API fetch tester, your request goes directly from your browser to the endpoint you specify; it does not pass through ToolsVenue servers. The AI tools in AI and content tools, forward submitted input through ToolsVenue and OpenRouter to a third-party AI provider.
What does the Color Contrast Checker test against? ▾
The colour contrast checker tests foreground/background colour pairs against the WCAG 2.1 AA and AAA contrast ratio thresholds (4.5:1 and 7:1 for normal text, 3:1 and 4.5:1 for large text). The result tells you whether each combination passes or fails each level.
How do I calculate chmod permissions for a file? ▾
Enter the permission bits you want for Owner, Group, and Others (read, write, execute) in the chmod calculator. The tool outputs the numeric octal value (e.g., 755 or 644) and the symbolic notation you can use in a terminal command.
Should I minify CSS and HTML if my server already uses gzip? ▾
The gain is smaller than the tools' own percentage counters suggest. Gzip and Brotli already collapse repeated whitespace very efficiently, so running the CSS minifier or HTML minifier on top of compression typically saves single-digit percentages on the wire rather than the 20–30% the before/after byte count implies. It is still worth doing on files you ship often; it is not worth breaking a build over.
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Over 40 web tools — many process input locally; AI features use third-party services. No ToolsVenue signup.