NKable's code tools validate, format, convert and test: JSON, YAML, CSV, HTML and CSS validators that report errors by line, a multi-language beautifier and minifier, a format converter, and a REST API tester. All run in your browser.

These code tools cover the checks that belong before a commit rather than after a failed deploy. Validating a config file, beautifying a minified bundle to read it, converting between data formats, or firing a request at an endpoint to see what it actually returns.

Each validator reports the line and position of a problem rather than just refusing the input. That is the difference between a useful tool and a red cross — knowing a YAML file is invalid helps far less than knowing which line broke it.

Everything runs in your browser, so config files, API keys in a request header and proprietary source never leave your machine. There is nothing to install, which is the point when you are checking one file on a machine that is not yours.

How to use the Code Tools

Pick a tool. Choose a validator, formatter, converter or the API tester.
Paste your input. Enter the code, data or request details.
Read the result. Errors are reported with line numbers where applicable.
Copy or act on it. Take the formatted output, or fix the reported problem.

Code Tools features

JSON, YAML, CSV, HTML and CSS validation
Errors reported with line and position
Beautifier and minifier for several languages
Format conversion between JSON, YAML, CSV and Base64
REST API testing with custom headers and bodies
Everything runs in your browser

Frequently asked questions

Which languages and formats are covered?

JSON, YAML, CSV, HTML and CSS for validation, plus JavaScript, TypeScript, SQL and XML for formatting.

Do the validators say where the error is?

Yes. Each reports the line and position of the problem rather than only that the input is invalid.

Is my code uploaded?

No. Everything runs in your browser, so config files and proprietary source stay on your machine.

Do I need to install anything?

No. These are browser tools, which is what makes them useful on a machine that is not your own.

Are they free?

Yes, with no account, no rate limit and no paid tier.