Developer tools
Open Developer tools on Happytails.ai. This view has the same page content and links, with explicit tool capabilities. Read the processing notes before using a tool.
Page guide
Find the right tool and get straight to your task.
No account needed.JSON formatter
Turn dense JSON into readable, properly indented data.
Base64 encoder decoder
Encode text as Base64, or turn Base64 back into readable text.
Binary to text
Decode binary byte values into UTF-8 text.
Unix timestamp converter
Turn a Unix timestamp into a readable date, or convert a date back.
JSON validator
Find the syntax errors keeping your JSON from parsing.
XML formatter
Format XML for reading or minify it for a compact result.
Regex tester
Try a JavaScript regular expression and see what it matches.
URL encoder decoder
Encode a URL component or make its encoded characters readable again.
UUID generator
Generate UUIDs when you need fresh identifiers.
JWT decoder
Read a JWT's header and payload without verifying its signature.
SQL formatter
Lay out your SQL queries so they are easier to follow.
HTML formatter
Make your HTML source easier to read.
JSON diff
Find added, removed and changed values between two JSON documents.
JSON to schema
Create a starting JSON Schema from sample data.
Token counter
Estimate token usage with the selected tokenizer.
XML validator
Check whether your XML is well formed.
YAML validator
Find syntax errors that stop your YAML from parsing.
Hex to text
Decode hexadecimal byte values into UTF-8 text.
Number base converter
Move a number between binary, octal, decimal and hexadecimal.
Javascript minifier
Reduce JavaScript file size without running the code.
YAML formatter
Give your YAML consistent, readable formatting.
Chmod calculator
Translate numeric Unix permissions into readable rwx flags.
Javascript formatter
Make JavaScript easier to read without running it.
JSON schema validator
Check JSON against a schema and find the values that do not fit.
All tools (129)
About developer tools
These free developer tools handle the small jobs that interrupt real work. The JSON formatter and JSON validator clean up and check API responses, the Base64 encoder decoder and URL encoder decoder handle encoding, and the Unix timestamp converter turns epoch values into readable dates. You can also test patterns in the Regex tester, inspect tokens with the JWT decoder, format SQL or XML, generate UUIDs and read cron schedules with the Cron parser.
Choose the narrowest tool for the job. A validator tells you where input breaks, while a formatter only rearranges it. For secrets such as JWTs or private keys, use a tool that runs in your browser and avoid pasting live production credentials into any website.
Popular developer tools
- JSON formatter
- Base64 encoder decoder
- Unix timestamp converter
- Regex tester
- URL encoder decoder
- JSON validator
Common questions
Is it safe to paste tokens or API responses here?
The JSON formatter, JSON validator, Base64 encoder decoder, URL encoder decoder and Regex tester run in your browser, so input is not sent to our server. Even so, treat live credentials with care and rotate any secret you suspect was exposed.
Which regex flavor does the Regex tester use?
The Regex tester uses the JavaScript regular expression engine built into your browser. Most common syntax matches other languages, but features such as lookbehind support or named group syntax can differ. Test against the engine you will run in production as well.
Why does Base64 output look different from another tool?
Differences usually come from text encoding, line breaks or the URL safe alphabet, which swaps two characters and may drop padding. Check that both tools use UTF-8 and the same alphabet before comparing results.