Free Developer Tools
Format JSON, convert Unix timestamps, encode Base64, decode JSON Web Tokens, diff text, test regular expressions and send REST API requests — fast, private browser tools. Everything runs locally, nothing is uploaded, and there is no sign-up.
JSON Formatter
Format, validate, beautify and minify JSON with clear error messages and a collapsible tree view. Paste, fix and copy in seconds.
Open JSONJSON Minify
Compress JSON to its smallest valid form, stripping every unnecessary space and newline. See the exact bytes saved. Fully client-side.
Open JSONJSON Diff
Compare two JSON objects structurally — added, removed and changed values by path, with key order and formatting ignored. Nothing uploaded.
Open JSONJSON Escape / Unescape
Escape any text into a valid JSON string, or unescape a JSON string back to raw text. Handles quotes, backslashes and newlines. Client-side.
Open TimeEpoch & Unix Timestamp Converter
Convert a Unix timestamp to ISO 8601, UTC, local and relative time — seconds to nanoseconds auto-detected — or a date to epoch. Live current epoch with copy.
Open SQLSQL Formatter & Minifier
Beautify or minify SQL for PostgreSQL, MySQL, SQLite, BigQuery, T-SQL and more — with keyword casing and indent control. Fully client-side.
Open XMLXML Formatter
Beautify and pretty-print XML with clean indentation, or minify it to one line — validated in your browser. Nothing uploaded.
Open HTMLHTML Formatter
Beautify and pretty-print HTML with clean indentation, or minify it — pre, script and style left intact. Runs entirely in your browser.
Open ReferenceASCII Table
The full ASCII table — decimal, hex, octal, binary, HTML entity and character for all 128 codes. Searchable, click to copy.
Open ReferenceHTTP Status Codes
Every HTTP status code — 200, 301, 404, 500 and more — with its name and meaning, grouped 1xx to 5xx. Search by number or name.
Open ReferenceChmod Calculator
Tick read, write and execute for owner, group and other to get the octal (755) and symbolic (rwxr-xr-x) permissions and command.
Open MinifyCSS Minifier
Compress CSS by stripping comments and whitespace to the smallest form. See the bytes saved. Runs entirely in your browser.
Open MinifyJS Minifier
Shrink JavaScript by removing comments and whitespace — string- and regex-aware, so your code keeps working. In your browser.
Open TimeCron Expression Generator
Describe any cron schedule in plain English and see the next run times. Presets for the common schedules.
Open AuthJWT Encoder
Build a JSON Web Token from a payload and sign it with HS256/384/512 using Web Crypto — your secret never leaves the page.
Open MarkdownMarkdown Viewer & Preview
Live Markdown-to-HTML preview with tables, code blocks and syntax highlighting — plus print-to-PDF. Runs entirely in your browser.
Open EncodingBase64 Encoder & Decoder
Convert text to Base64 and back — UTF-8 safe (emoji included), with a URL-safe option. Runs entirely in your browser, nothing uploaded.
Open EncodingURL Encoder & Decoder
Percent-encode and decode URLs and query strings — UTF-8 safe, with an HTML-entity mode. Everything runs in your browser, nothing uploaded.
Open AuthJWT Decoder
Decode a JSON Web Token's header and payload with human-readable expiry. Decode-only — your token never leaves the browser.
Open CompareText Diff
Compare two blocks of text line by line and see exactly what was added or removed, with counts. Instant and fully client-side.
Open RegexRegex Tester
Test a regular expression against your text live — matches highlighted and counted, with captured groups. Uses the JavaScript engine.
Open HTTPAPI Tester
Send HTTP requests to any REST API and inspect the status, timing, headers and body. Works with public endpoints and localhost.
OpenFrequently Asked Questions
What are the LK Forge Developer Tools?
A free suite of browser-based developer utilities covering JSON (formatter, minify, diff, escape/unescape), encoding (Base64), auth (JWT decoder), time (epoch/Unix timestamp converter), SQL formatting, text diff, regex testing and REST API testing. Everything runs in your browser — nothing you paste is uploaded or stored — and there is no sign-up. Each tool is a single-purpose page that works the same way: paste your input, press the action button, and copy the result, with no install, build step or configuration.
Are the developer tools free and private?
Yes — the developer tools cost nothing and keep your data private. Every tool is completely free with no account and no usage cap. All work runs client-side in JavaScript, so nothing you paste leaves your device, and each tool keeps working offline once loaded.
Does the JWT Decoder verify the signature?
No — the JWT Decoder does not verify the signature. The decoder is decode-only: it reads and displays the header and payload so you can inspect a token's claims and expiry, but it never checks the signature and never sends the token anywhere. Verifying a signature requires the issuer's secret or public key, so it belongs in your backend rather than in a browser page.
Do the developer tools work offline?
Once a developer tool page has loaded, it keeps working offline, because the work happens in your browser rather than on a server. The one exception is the API Tester, which by design sends an HTTP request to whatever endpoint you name, so it needs a network route to that host. Everything else — the JSON formatter, minifier, diff and escaper, Base64, the JWT decoder, the epoch converter, the SQL formatter, the text diff and the regex tester — runs entirely on your device.