5 free tools
Developer tools built for real work
Fast browser utilities for everyday data and encoding tasks. Every tool is designed to expose its inputs and outputs clearly instead of hiding the logic behind a vague score.
</>JSON Formatter & ValidatorValidate, pretty-print and minify JSON locally in your browser.→</>Base64 Encoder & DecoderEncode or decode UTF-8 text as Base64 locally without uploading it.→</>JSON Diff CheckerCompare two JSON documents locally and list added, removed and changed paths.→</>Unix Timestamp ConverterConvert epoch values in seconds or milliseconds to readable UTC/local dates, or turn a date into Unix time without sending data anywhere.→</>YAML ↔ JSON ConverterConvert common YAML configuration data to JSON or turn JSON into readable YAML. Parsing happens locally in your browser.→
Why ToolboxKart Developer tools?
Fast interfaces, plain-language explanations, mobile-friendly layouts and no unnecessary account wall for the utilities in this release.
Tool first
The working interface appears before long-form SEO content, so you can finish the task quickly.
Transparent logic
Calculators disclose formulas or assumptions where they matter, and analyzers avoid pretending subjective checks are scientific facts.
Reusable results
Copyable output and clean formatting are included where they improve the workflow.