freesabaiFree · no sign-up · what you paste stays on your device
Developer tools
The small tools developers reach for every day: format JSON, convert data, encode, hash, decode a JWT, generate UUIDs, test a regex, convert times. Every one runs in your browser. The text, files and tokens you paste are not sent anywhere.
All developer tools
Most used
- JSON formatter and validatorFormat, minify and validate JSON, find the error, fold it into levels
- Base64 encode and decodeBase64 for text (Thai and UTF-8), URL-safe, and files to and from Base64
- UUID generatorMake UUID v4 and v7, many at once, copy them all
- Password generatorMake strong random passwords, choose length and characters, made on your device
- Unix timestamp converterConvert a timestamp (seconds or milliseconds) to a date and back, with time zones
- Regex testerTry a regular expression, see matches and groups, protected from regexes that never finish
JSON and data
- JSON formatter and validatorFormat, minify and validate JSON, find the error, fold it into levels
- JSON to YAML converterTurn JSON into YAML, key order kept, nothing leaves your device
- YAML to JSON converterTurn YAML into JSON, and find the line where the YAML is wrong
- JSON to CSV converterTurn a JSON list into CSV for Excel, Thai text included
- CSV to JSON converterTurn CSV into JSON, any separator, quoted fields handled
- CSV viewerOpen a CSV file as a table, sort a column, search, no spreadsheet needed
- Text and JSON diff checkerSee what changed between two texts, side by side or unified, with word highlights
Encoding, hashes and tokens
- Base64 encode and decodeBase64 for text (Thai and UTF-8), URL-safe, and files to and from Base64
- Hash generator: MD5, SHA-256, HMACHash text or files with MD5, SHA-1, SHA-256, SHA-512 and HMAC, and verify a checksum
- JWT decoderRead the header and payload of a JWT, with times you can read (decode only, no signature check)
- URL encode and decodePercent-encode or decode a link, Thai in URLs included, and take a URL apart
- HTML entities encode and decodeTurn special characters into & < > " and back
Generators
Time, numbers and colour
- Unix timestamp converterConvert a timestamp (seconds or milliseconds) to a date and back, with time zones
- Cron expression explainerRead a cron expression in plain words and see its next 5 runs
- Number base converterConvert between binary, octal, decimal and hex, and do bitwise AND, OR, XOR and shifts
- Colour converter: HEX, RGB, HSLConvert a colour between HEX, RGB and HSL, or pick one by eye
- Colour contrast checker (WCAG)Check the contrast between text and background colours for WCAG AA and AAA
Text and code
- Regex testerTry a regular expression, see matches and groups, protected from regexes that never finish
- Markdown previewType Markdown and see it rendered at once, safely, with embedded scripts never run
- Character, word and line counterCount characters, words (Thai too), lines, sentences, paragraphs and reading time
What you paste stays here
Every tool on this page runs entirely in your browser. The JSON, text, tokens, passwords and files you paste or open are not uploaded to freesabai's servers or anyone else's, and are not kept in the browser: close the page and they are gone. The site only counts how many times a page was opened and how many times someone copied or saved a result, without what was pasted or the result, and you can switch the counting off in the footer (see the privacy policy).
Even so, we advise not pasting a real password or a live system's token into any online tool, ours included: browser extensions and programs on your computer can read what is on a page.
Report a problem or suggest an idea
Found a bug, want a tool to do more, or want another tool? Tell us on the feedback page. No sign-up.