OnlineDeveloperTool
14 tools

JSON Tools Online

JSON is the default format for APIs, config files and logs, and most of the time the problem is the same: the JSON is on one line, or it will not parse. These tools cover the everyday jobs. Format or beautify a payload so you can read it, validate it to find the syntax error, or minify it for a request body or environment variable.

When you start from a sample response, the converters write a first draft of a class or type in C#, TypeScript, Java, Python, Go, PHP or Kotlin. For data moving in and out of spreadsheets and config files there are JSON to CSV, CSV to JSON and YAML to JSON converters.

Which json tools tool do you need?

  • The JSON is one unreadable line: JSON Formatter. Format it with indentation. The beautifier does the same job with wording aimed at minified input.
  • JSON.parse is throwing an error: JSON Validator. Find out whether it parses and read the parser message. Trailing commas, single quotes and unquoted keys are the usual causes.
  • You need the smallest possible JSON: JSON Minifier. Strip whitespace without changing the data.
  • You need a model class from a response: JSON to C#. Generate a first draft in C#, then see the TypeScript, Java, Python, Go, PHP and Kotlin converters in the list below.
  • The data lives in a spreadsheet or a YAML file: JSON to CSV. Move between JSON and CSV, or turn YAML into JSON with the YAML to JSON converter.

All json tools

More developer tool categories

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.

Three steps: paste your input, click the tool, copy the result, all inside your browser
Popular developer utilities: JWT decoder, UUID generator, Base64 decoder, SHA-256 hash, regex tester and timestamp converter

What you can do here

  • JSON Tools

    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.

  • Encoders & Decoders

    URL, Base64 and HTML encoding and decoding, plus a JWT decoder for reading token claims.

  • Generators & Hashes

    Generate UUIDs and JWTs, validate UUIDs, and create MD5, SHA-256 and SHA-512 hashes.

  • Web Tools

    Timestamps, color codes, query strings and cron expressions - the small things web work keeps throwing at you.

  • Text & Data

    Format XML and YAML, count text, change case, make slugs, test regex, diff two texts and convert number bases.

  • Website Checking

    Check whether a website or URL is reachable from your browser.

Quick developer reference

  • JSON

    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 JSON

  • JWT

    A 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 JWT

  • Base64

    Base64 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 Base64

  • UUID

    A 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 UUID

  • Timestamps

    A Unix timestamp counts time since 1 January 1970 UTC. Ten digits usually means seconds and thirteen digits usually means milliseconds.

    Convert a timestamp

  • Hashes

    MD5 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 hash

Missing 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.