Free Developer Tools for JSON, Regex, JWT, CSV, XML, URLs, and Code
Format JSON, inspect XML, test regex, decode JWTs, compare data, clean CSV, and debug small code or API problems.
All Developer Tools
10 ToolsURL Encoder / Decoder
Open URL Encoder / Decoder when your URL text needs one clear change. The tool keeps the process short and the encoded or decoded text easy to inspect.
HTML Formatter
Use HTML Formatter when you need to make messy code or data easier to read. Add the code or data, choose the option that matters, and review the formatted output.
CSS Formatter
Use CSS Formatter when you need to make messy code or data easier to read. Add the code or data, choose the option that matters, and review the formatted output.
JS / TS Formatter
Use JS / TS Formatter when you need to make messy code or data easier to read. Add the code or data, choose the option that matters, and review the formatted output.
Regex Tester
Regex Tester helps when the next step is simple: run a pattern against sample text and see what matches. It is built for quick fixes, checks, and downloads.
UUID / GUID Generator
UUID / GUID Generator helps when the next step is simple: create a ready-to-use output from selected settings. It is built for quick fixes, checks, and downloads.
Hash Generator
Open Hash Generator when your settings needs one clear change. The tool keeps the process short and the generated result easy to inspect.
XML Viewer / Formatter
Open XML Viewer / Formatter when your code or data needs one clear change. The tool keeps the process short and the formatted output easy to inspect.
JSON Diff Checker
Open JSON Diff Checker when your two JSON inputs needs one clear change. The tool keeps the process short and the difference report easy to inspect.
SQL Formatter & Validator
Open SQL Formatter & Validator when your code or data needs one clear change. The tool keeps the process short and the formatted output easy to inspect.
Start with the smallest code check
Developer tools are best for quick checks: make code readable, catch syntax mistakes, or compare two versions.
Checked by Tooliofy Team · June 22, 2026
Format
The code or JSON is valid but hard to read.
The problem is broken logic or missing data.
Validate
You need to catch syntax errors, bad JSON, or invalid markup.
You need to confirm the data is correct for your app.
Compare
Two versions look almost the same and you need the exact difference.
The text contains secrets, tokens, or private config.
Debug Small Data Problems Faster
- Step 1
Paste only the relevant snippet
Use the smallest JSON, token, regex, or data sample that reproduces the problem.
- Step 2
Format or decode it
Make the structure readable before changing anything.
- Step 3
Fix and test
Adjust the data, pattern, or structure, then test against a few realistic cases.
- Step 4
Move the result back to code
Copy the cleaned output into your editor, test suite, API client, or documentation.
Which developer tool should you open?
Use the tool that answers the immediate question.
JSON hard to read?
Format it first, then validate it.
Two payloads changed?
Use a diff before guessing.
Regex too broad?
Test it against real examples.
Token looks wrong?
Decode it, then verify trust inside your app.
Developer tool limits
A formatter does not fix broken logic.
A decoded JWT is not automatically trusted.
A valid payload can still be wrong for your API.
Use sample data when possible.
Developer tools should answer small questions quickly
Sometimes you do not need a full project open. You just need to know if JSON is valid, why a regex matches too much, what is inside a token, or how two data blocks differ.
Format before debugging
Minified JSON, XML, CSS, or JavaScript can hide obvious mistakes. Formatting first makes missing commas, broken nesting, and wrong values easier to spot.
Validation is not business logic
A validator can tell you if JSON or XML is well formed. It cannot tell you if the data is correct for your app, customer, or API contract.
JWT decoding is not verification
A JWT decoder makes the header and payload readable. It does not prove the token is trusted. Signature, issuer, audience, and expiry still need to be checked by your application.
Regex should be tested with real samples
A pattern that works on one line may fail on real logs, names, URLs, or multiline text. Test a few examples before using it in production.
Keep private data out of quick tests when possible
Use sample data for debugging. If you must inspect real data, remove secrets, tokens, and customer details first.
Example: API response is unreadable
If an API response is minified into one long line, format it first. You may spot a missing field or wrong value without opening a debugger.
Formatter vs validator
A formatter makes code readable. A validator checks if the structure is legal. A file can be formatted nicely and still be wrong for your app.
JWT decoder limit
Decoding a token only shows its contents. It does not verify the signature or prove the token should be trusted.
Regex needs real examples
Test regex patterns against real strings, not only perfect samples. Logs, names, URLs, and multiline text often reveal problems.
Use fake data when possible
When testing formatters, decoders, or converters, use sample values instead of real passwords, tokens, customer data, or private payloads.
Common developer tasks
Format a JSON API response.
Decode a JWT while testing login.
Test a regex before adding it to code.
Convert CSV to JSON for a small import.
Compare two JSON blocks to find a changed value.
Developer Tool Questions
Practical notes about JSON, JWTs, regex, formatters, converters, and safe debugging.
Can a JSON formatter fix invalid JSON automatically?
Is decoding a JWT enough to verify it?
Why does my regex work in one tool but not in my app?
Should I paste production API keys into a formatter?
What should I check before converting CSV to JSON?
Are beautifiers safe for minified code?
Developer tools are most useful when they answer one question quickly. Format, compare, decode, or test the input, then verify the result in your real project.
Explore Other Categories
19 ToolsPDF & Documents
Explore our pdf & documents and start processing your files securely.
5 ToolsAI Tools
Explore our ai tools and start processing your files securely.
58 ToolsImage Tools
Explore our image tools and start processing your files securely.
24 ToolsText Utilities
Explore our text utilities and start processing your files securely.