Have a question, feedback, or suggestion for a new developer tool? We would love to hear from you!
You can reach our team directly via email at: contact@onlinedevelopertool.com
Please note that because our tools run entirely client-side without a backend database, we cannot recover or access any code or data you paste into the utilities.
onlinedevelopertool.com is a collection of 54 free, browser-based utilities for the small jobs that interrupt real work: formatting a JSON response, decoding a token, converting a timestamp, generating a UUID or checking a hash. Each tool has its own page with a short explanation, a worked example and answers to common questions, so you can use it and learn what it does at the same time.
There is no account to create and nothing to install. Tools run in your browser, so the text you paste is processed on your own device. The one exception is the Website Status Checker, which sends a request from your browser to the address you enter.
Format, validate, beautify and minify JSON, generate C#, TypeScript, Java, Python, Go, PHP and Kotlin models from it, or convert between JSON, YAML and CSV.
URL, Base64 and HTML encoding and decoding, plus a JWT decoder for reading token claims.
Generate UUIDs and JWTs, validate UUIDs, and create MD5, SHA-256 and SHA-512 hashes.
Timestamps, color codes, query strings and cron expressions - the small things web work keeps throwing at you.
Format XML and YAML, count text, change case, make slugs, test regex, diff two texts and convert number bases.
Check whether a website or URL is reachable from your browser.
Keys and strings must use double quotes, and trailing commas and comments are not allowed. Those are the three most common reasons a payload fails to parse.
Validate JSONA JSON Web Token is three Base64URL parts joined by dots: header, payload and signature. Decoding shows the claims but does not prove the token is genuine; only signature verification does.
Decode a JWTBase64 is an encoding, not encryption. Anyone can reverse it, and it makes data roughly one third larger, so never use it to hide secrets.
Decode Base64A version 4 UUID is made of random bits and written as 8-4-4-4-12 hexadecimal characters. Collisions are astronomically unlikely, which is why they work well as identifiers.
Generate a UUIDA Unix timestamp counts time since 1 January 1970 UTC. Ten digits usually means seconds and thirteen digits usually means milliseconds.
Convert a timestampMD5 is fine for quick checksums but is not safe for security. Prefer SHA-256 or SHA-512, and remember that hashing is one-way and is not encryption.
Create a SHA-256 hashMissing a tool you need? Visit the contact page and tell us what you reach for most often. You can also browse every tool or read the About page to see how the site is built and what it does with your data.