💻 Developer tools

Developer tools collection

From the JSON formatter and viewer to Base64 encoding/decoding, base conversion, the HTML color code chart, and the live editor, we have gathered in one place utilities often used in web development. Markdown to HTML conversion, AI API cost calculation, and password strength checking are provided as well, so you can quickly finish formatting, encoding, conversion, and checking. Every tool runs right in the browser with no installation or sign-up, and the code and data you enter are processed only on the device and are not sent to a server.

HTML live editorCode writing and preview Free Markdown to HTML conversionReal-time Markdown to HTML conversion Free JSON formatter & viewerFormat, minify, and check syntax errors Free Base64 encoding/decodingUTF-8 text conversion Free Number base converterConvert number bases with prefixes, bits, and worked steps Free HTML color code chart & color pickerColor code chart · HEX↔RGB↔HSL conversion · contrast Free AI API cost calculatorCompare token cost by model Free Password strength checkerEntropy, pattern, and 4-type crack time analysis Free

Which tool should you use?

If you choose the situation first, you can go straight to the matching tool.

When an API response is crammed into one line and is hard to read JSON formatter & viewer It expands the structure with indentation and a tree view and points out syntax errors.

When you need to send an image or a file carried as text Base64 encoding and decoding converter It converts text and files in both directions and creates a Data URI.

When checking a base 16 color value or a Unicode code point in base 10 Number base converter It converts base 2, base 8, base 10, and base 16 numbers to each other on one screen.

When you need to move a document you wrote into HTML Markdown to HTML converter It converts Markdown syntax to HTML and lets you check the result right away.

When choosing a UI color value and checking the contrast HTML color code chart & color picker It provides HEX, RGB, and HSL conversion together with a WCAG contrast determination.

When you want to see the render result immediately while fixing HTML HTML live editor It lets you check editing and the preview in real time on one screen.

Tools to use together

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Frequently asked questions

Is the code or data you enter sent to the server?

No. All processing, such as JSON formatting, Base64 encoding, and base conversion, runs only inside the browser. The code or text you enter is not sent to a server or stored, and login and installation are not required either.

Which tool should you use, and when?

To tidy an API response so it is easy to read, use the JSON formatter, use Base64 for data encoding, and use the base converter for radix calculation. The HTML color code chart is suitable for UI work, Markdown to HTML conversion is suitable for writing documents, and the password strength checker is suitable for a security check.

Is everything really free?

Yes. Every developer tool can be used for free with no sign-up or payment. There is no limit on the number of uses, and there is no feature lock caused by ads.