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Free developer tools

Small tasks. Clear results.

Format JSON, compare text, test regex, encode URLs and convert timestamps. Fast browser tools with clear results and nothing to install.

Open JSON formatter ↓

Your everyday developer toolkit

JSON Formatter & ValidatorFormat, validate or minify JSON in your browser. Choose indentation, inspect syntax errors, copy the result or download a local JSON file.Text Diff Checker — Compare Two TextsCompare original and changed text line by line. Inspect additions, removals, line numbers and unchanged content, then copy or download the comparison.JavaScript Regex Tester — Matches & Capture GroupsTest JavaScript regular expressions against text. Inspect match positions, numbered and named capture groups, with worker isolation and a timeout.URL Encoder & Decoder — Components & Query StringsEncode URL components, decode percent escapes, or parse and build query strings while preserving duplicate keys and empty values.Unix Timestamp Converter — Seconds, Milliseconds & ISOConvert Unix seconds or milliseconds to UTC and a selected timezone, or turn an explicit ISO date with timezone into Unix time.
◈ Processed in your browser · inputs are not saved

JSON uses JavaScript number precision; duplicate keys keep their last value.

Inputs stay in page memory. Only your theme preference is saved.

How it works

DevKit brings five everyday development tasks into one place. Paste a JSON response to inspect its structure, compare a changed configuration, test a JavaScript pattern, check a query parameter or convert a Unix timestamp. Tools run on your device, and pasted inputs are not stored by the app or sent to a processing service. Only the display theme is remembered. Each page includes a worked example, operation limits and the assumptions that affect the result. Copy the output or download a local file when you are finished. Changing language navigates to the same tool, but deliberately does not carry your pasted code into the next page.

Limits and behavior

Start with Load example to see the expected input shape. Replace the example with your own text and choose the relevant operation. Editing an input invalidates the previous output so an old result cannot be copied as if it were current. Copy and download buttons become available after a successful run. Clear removes the visible inputs and output from the page. Limits keep small development tasks responsive; use a local editor or dedicated command-line utility for very large files. A successful transformation does not validate your application logic or make untrusted data safe to execute.

Frequently asked questions

Are pasted inputs saved or uploaded?

No. These tools process input in page memory. Only the selected display theme is stored. Reloading or changing language resets inputs. Your browser may independently offer form restoration.

Can I use the tools without signing in?

Yes. No account, API key or installation is required. JavaScript must be enabled. Each tool provides example input and a local output download.

Why did my previous output disappear?

Editing an input marks the old result as stale. Run the tool again before copying or downloading. This avoids mixing an earlier result with changed input.