Popular Developer Tools

Free browser-based tools for API development, data formatting, testing, and productivity.

JSON Formatter

Format, validate, and beautify JSON instantly for debugging and development.

API Request Tester

Send HTTP requests, inspect responses, and test REST APIs directly in your browser.

Mock API Generator

Create mock API endpoints for frontend development and integration testing.

PDF Tools

Merge, split, and convert PDF files without installing additional software.

Everything you need for modern development

From API testing and JSON formatting to security utilities and file conversion tools.

API Tools

2 Tools

• API Request Tester
• Mock API Generator

Encoders & Security

4 Tools

• Base64 Encoder & Decoder
• URL Encoder & Decoder
• JWT Decoder
• Regex Playground

Formatters & Data

3 Tools

• JSON Formatter
• JSON to CSV
• SQL Formatter

File & PDF Tools

4 Tools

• Merge Tool
• Split Tool
• PDF Organizer
• PDF & Image Converter

See how MCYG tools work

Explore the most-used developer workflows, from API testing and mock data generation to JSON formatting and debugging.

1

Test APIs

Send HTTP requests, inspect responses, and debug REST endpoints directly from your browser.

2

Generate Mock APIs

Create fake endpoints and realistic JSON responses for frontend development and testing.

3

Format JSON

Beautify, validate, and inspect JSON data with a clean developer-friendly interface.

Questions before using MCYG?

Everything you need to know about our tools, privacy, and platform access.

Data Formatters & Privacy

Data structure validation and client-side safety.

Encoders & Security Decoders

Secure data encoding and token verification.

API Testing & File Management

Local request execution and document processing.

Is it safe to format and validate JSON online?

Yes. This safe JSON validator online processes data entirely in your browser using client-side JavaScript. Your sensitive production data is never sent to an external server, logged, or exposed, ensuring 100% data privacy.

What is the difference between formatting, beautifying, and pretty printing JSON?

There is no functional difference. Developers use a beautify JSON tool to turn minified, single-line data into an unminified, readable layout. All terms mean adding clear indentations and line breaks.

Can this JSON to CSV converter handle deeply nested arrays?

Yes. When you convert JSON to CSV online, this utility flattens flat structures seamlessly. For deeply nested arrays, it serializes sub-objects into readable strings to preserve layout integrity inside Excel sheets.

Does this SQL Formatter support custom syntax capitalization rules?

Yes. This SQL formatter pretty print engine handles MySQL and PostgreSQL structures. You can enforce capitalization rules for commands like SELECT or WHERE and set custom tab indentation parameters.

Can an online JWT decoder steal or read my secret key?

No. To decode JWT token online, the browser only parses the payload claims, which are public Base64Url strings. Because execution happens locally inside your machine, your private signature keys remain secure.

Why does Base64 encoding sometimes add equals (=) signs at the end?

The trailing equals signs are padding. A Base64 encoder decoder tool splits characters into 3-byte blocks. If your raw text length isn't a multiple of three, padding characters are appended.

What is the difference between standard Base64 and URL encoding?

Standard Base64 outputs characters like + and / which break web paths. This online URL encoder decoder converts unsafe characters into percent-encoded fragments like %2B for safe HTTP transmissions.

Which engine does this online Regex Playground use to test patterns?

This regex tester online natively runs the ECMAScript JavaScript pattern matching engine. It provides lightning-fast matching feedback for global, case-insensitive, and multiline expression flags directly in your browser.

Can this browser-based API Tester send requests to localhost?

Yes. This free online API tester executes network calls directly from your local browser engine. This lets you debug internal network servers and localhost configurations without exposing endpoints to cloud servers.

Does the Mock API Generator support custom HTTP status codes?

Yes. The mock API generator online can be configured to simulate network states. You can test client-side handlers against custom HTTP status codes like 200 OK, 404 Missing, or 500 Failure.

Is there a file size limit for the online merge and split tools?

No. You can merge large files online or split text documents without payload caps. Processing is handled using your device's memory pool, bypassing restrictive web server upload limitations completely.

Does converting a PDF to an image reduce text quality?

No. To convert PDF to image high resolution, our converter turns documents into crystal-clear vector PNG or JPEG assets. Text, geometry, and layout typography lines stay sharp across mobile and desktop displays.