Current privacy posture
No account. No database. Current tools are designed to run in your browser, and optional pageview analytics are disabled by default.
A quiet toolbox for everyday text and data.
Small tools for Japanese forms, writing cleanup, dates, Markdown, and developer snippets.
Quick tools
A few practical entry points before the full directory.
Text tools
Environment-dependent / Machine-dependent Character Checker
Check Japanese compatibility characters before email, forms, or submission.
Conversion tools
Unix Timestamp Converter
Convert Unix timestamps and date/time values.
Developer tools
CIDR / Subnet Calculator
Calculate IPv4 CIDR ranges, usable IPs, and overlap checks.
Long-weekend guides
Check confirmed holidays and useful leave dates by year.
Japanese text & forms
Practical helpers for Japanese forms, dates, character width, and copied text cleanup.
Age Calculator
Calculate age, school years, and resume education-year hints.
Japanese Era Converter
Convert dates between Gregorian years and Japanese eras.
Paid Leave & Long Weekend Planner
Find long weekends using confirmed Japanese holidays and up to ten paid leave days.
Full-width / Half-width Converter
Convert Japanese full-width and half-width text.
Kana Converter
Convert hiragana, katakana, and half-width kana.
Environment-dependent / Machine-dependent Character Checker
Check Japanese compatibility characters before email, forms, or submission.
Line Break and Space Cleaner
Clean line breaks, spaces, tabs, and blank lines from copied text.
Writing & Markdown
For notes, docs, tables, and text length checks.
Images & files
Prepare images for web layouts, cards, forms, and handoff.
Developer cleanup
Format, decode, and review small technical snippets.
JSON Formatter
Format, validate, and beautify JSON.
SQL Formatter
Format SQL queries for review and sharing.
URL Encode / Decode
Encode and decode URL components for query strings and copied links.
Base64 Encode / Decode
Encode and decode Base64 text, including Unicode characters.
JSON / CSV Converter
Convert between JSON and CSV, including nested JSON columns.
Developer quick checks
Small helpers for timestamps, tokens, ARNs, CIDR, identifiers, and checksums.
Unix Timestamp Converter
Convert Unix timestamps and date/time values.
JWT / OIDC Token Decoder
Decode JWT header and payload claims for debugging.
AWS ARN Parser
Split AWS ARNs into service, region, account, and resource parts.
CIDR / Subnet Calculator
Calculate IPv4 CIDR ranges, usable IPs, and overlap checks.
UUID Generator
Generate UUID v4 values.
Hash Generator
Generate SHA hashes for text.
Small break
A calm practice corner when you want one minute away from formatting work.
Open tool data
Open tool data is available through tools.json and llms.txt.