TOOLBOX / 50 TOOLS
Small tools. Clear answers.
50 tools for encoding, networking, writing and development. No sign-up; input stays in this browser.
JSON formatter & validator
Validate standard JSON and indent with two spaces. Use double-quoted keys and strings; comments are unsupported.
JSON minifier
Minify valid JSON into one line while preserving its parsed data structure.
Base64 encoder / decoder
Encode or decode UTF-8 text with standard Base64, including emoji. Base64 is not encryption.
URL encoder / decoder
Encode or decode a URL parameter value with encodeURIComponent, including spaces and Unicode.
HTML escape tool
Escape ampersands, angle brackets and quotes, or decode amp, lt, gt, quot and #39 entities.
Unicode escape tool
Encode text as UTF-16 \uXXXX sequences or decode them. Emoji use surrogate pairs.
SHA-256 hash generator
Compute a SHA-256 digest of UTF-8 text. Spaces, newlines and letter case affect the result.
MD5 hash generator
Compute an MD5 digest for legacy content comparisons. MD5 is unsuitable for passwords or security signatures.
Secure password generator
Enter a length from 8 to 128 to generate a password with letters, digits and symbols using cryptographic randomness.
UUID generator
Generate a new UUID v4 for test data and resource identifiers. No input is required.
Random string generator
Enter a length from 8 to 128 to generate a random string with letters, digits and symbols.
JWT decoder
Decode a JWT header and payload to inspect claims and algorithms. Signatures are not verified.
Regular expression tester
Put a JavaScript regex on line one without slash delimiters, then the test text. Long-running matches are stopped.
Unix timestamp converter
Convert Unix seconds, milliseconds and ISO dates. Select numeric units; dates require Z or a timezone offset.
Date difference calculator
Enter two YYYY-MM-DD dates on separate lines. Calculate the second minus the first at UTC midnight.
Timezone offset checker
Enter an IANA timezone such as Asia/Shanghai to compare its current time with UTC.
Cron expression helper
Explain the minute, hour, day, month and weekday fields of a five-field Cron. Execution times are not calculated.
Percentage calculator
Enter a base value on line one and percentage on line two to calculate a fraction, increase and decrease.
Ratio calculator
Enter a width-to-height ratio such as 16:9 on line one and width on line two to calculate height.
Average calculator
Separate numbers with commas, spaces or newlines to find count, sum, average, minimum and maximum.
Length unit converter
Enter a number and mm, cm, m or km, such as 12 cm, to convert lengths. The default unit is metres.
Bytes converter
Convert a non-negative byte count into decimal KB/MB and binary KiB/MiB units.
Color format converter
Normalize an opaque HEX, RGB or named CSS color into HEX and RGB representations.
Color contrast checker
Enter two opaque colors on separate lines to calculate contrast and check WCAG AA/AAA thresholds.
CSS gradient generator
Enter a direction and stops, such as 135deg, #3366ff 0%, #7c3aed 100%, to generate a CSS linear gradient.
CSS box-shadow generator
Enter shadow offsets, blur and color, such as 0 12px 30px rgba(0,0,0,.2), to validate and generate CSS.
Markdown preview helper
Preview # and ## headings and paragraphs. Raw HTML stays as text; full Markdown extensions are unsupported.
Slug generator
Turn a title into a lowercase hyphenated slug while preserving Unicode letters.
Word & character counter
Count characters, non-whitespace, Han characters, word groups and UTF-8 bytes. Word groups are not linguistic segmentation.
Line counter
Count all lines and lines with non-whitespace content. A trailing newline creates an empty line.
Text case converter
Produce uppercase and lowercase versions while preserving spaces and newlines.
Duplicate line remover
Remove identical duplicate lines while keeping first occurrences. Case and surrounding spaces affect equality.
Sort text lines
Sort one item per line with locale-aware comparison. Browser locale can affect the order.
Whitespace cleaner
Trim surrounding whitespace and collapse spaces, tabs and newlines into single spaces.
IPv4 to integer converter
Convert a four-octet IPv4 address into an unsigned integer in network byte order.
CIDR subnet calculator
Enter IPv4/prefix, such as 192.168.1.10/24, to calculate network, broadcast, mask and address counts.
IPv6 compressor
Expand and compress IPv6 zero groups. Omit ports, zone identifiers and CIDR suffixes.
Domain parser
Inspect an HTTP/HTTPS URL’s protocol, host, port, path and fragment without requesting the target.
Query string parser
Enter a full URL to decode query keys and values while preserving duplicates and their order.
User-agent inspector
Inspect this browser’s User-Agent, language, timezone and viewport size. No input is needed.
MIME type lookup
Look up a common extension or MIME type, such as jpg or application/json. File contents are not inspected.
HTTP status reference
Look up a common three-digit HTTP status code such as 404. No network request is sent.
Port reference
Look up a port such as 443 in a common TCP/UDP reference. This does not prove a service is running.
Color name lookup
Convert an opaque CSS color name such as rebeccapurple into HEX and RGB, not a nearest-name match.
Aspect ratio calculator
Reduce two positive dimensions separated by x, × or :, such as 1920x1080, to their simplest ratio.
Data URI helper
Encode UTF-8 plain text as a Base64 data URI with MIME text/plain; this is not an image converter.
HTML to Markdown helper
Convert HTML headings, list items and paragraphs into basic Markdown. Scripts, styles and layout are removed.
SQL formatter
Format common clauses in simple SQL with line breaks and uppercase keywords. No dialect validation or query execution.
YAML indentation checker
Check YAML indentation for tabs and common colon spacing. This is not complete syntax, type or anchor validation.
Log prettifier
Pretty-print one JSON object per line. Non-JSON log lines remain unchanged.