Developer Tools
Format JSON, decode JWTs, test regex, build cron expressions, minify code.
JSON Formatter & Validator
Pretty-print, minify and validate JSON with line-accurate error messages.
JWT Decoder
Decode a JWT token to view its header, payload and expiry — client-side only.
Regex Tester
Test regular expressions with live match highlighting and group capture.
Cron Expression Builder
Build cron expressions for Unix, Kubernetes, AWS EventBridge and Quartz — with a human-readable description and the next 5 run times.
AWS EventBridge Cron Generator
Generate 6-field AWS EventBridge cron expressions, see the next UTC run times, and copy ready-to-paste CloudFormation, Terraform and CLI snippets.
Kubernetes CronJob Schedule Generator
Build Kubernetes CronJob schedule strings, preview the next runs, and copy a complete CronJob YAML manifest.
HTML / CSS / JS Minifier
Minify HTML, CSS and JavaScript to reduce file size for production.
What are you debugging?
If an API response will not parse, the JSON Formatter & Validator pretty-prints valid JSON and reports the position of the failure when it is not. If a request is being rejected as unauthorised, the JWT Decoder shows the header, payload and expiry so you can see whether the token is malformed, expired or simply missing a claim. If a pattern is matching too much or too little, the Regex Tester highlights matches and capture groups live rather than making you redeploy to find out. If a scheduled job is running at the wrong time — or not at all — the Cron Expression Builder explains a schedule in plain English, with dedicated generators for AWS EventBridge and Kubernetes CronJob, whose field counts and day-of-week numbering differ from standard Unix cron in ways that quietly break schedules. And the HTML / CSS / JS Minifier strips bytes when you need a smaller payload without a build step.
The mistakes these tools exist to catch
JSON is stricter than JavaScript: no trailing commas, no comments, no single quotes, and keys must be double-quoted. A JWT is signed, not encrypted, so anyone holding the token can read its payload — never put a secret in a claim. Regular expressions are greedy by default and will happily match far more than intended across a line. Cron is where the sharpest edges are: Sunday is 0 in Unix but 1 in AWS, EventBridge takes six fields and requires a ? in one of the day positions, standard cron has no seconds field at all, and almost every platform defaults to UTC rather than your local time.
Safe to paste production data into
A JWT is a live credential and an API response often contains customer records, internal hostnames or keys. Pasting either into a website that round-trips it through a server is a genuine disclosure. Everything here executes in your browser — no request is made, so there is nothing to log, retain or leak.