Free Developer Tools Online - JSON, CSV, Regex & Encoding

Developer tools for everyday formatting and conversion

Developers spend surprising amounts of time reformatting data. These tools handle the usual suspects without installing anything or pasting sensitive payloads into a server.

JSON. Invalid JSON is almost always a trailing comma, a single-quoted string or an unescaped quote. The formatter points to the error and can minify the result for production. When converting JSON to CSV, remember the input must be an array of objects; nested objects are not flattened automatically.

Encoding. Base64 is an encoding, not encryption: anyone can reverse it. URL encoding replaces unsafe characters with percent codes so values survive inside links. HTML entity encoding stops user text from being interpreted as markup.

Time and IDs. Unix timestamps count seconds since 1 January 1970 UTC; 13-digit values are milliseconds. UUID v4 values are random 128-bit identifiers that are, for practical purposes, unique.

Regex. Test a pattern on realistic sample text, including the cases that should not match, before putting it into code.

Avoid pasting production secrets into any website. These tools run locally, but good habits cost nothing.