developer 8 min read

Developer Tools: Client-Side Debugging

JSON formatting, Base64 encoding, URL encoding, regex testing, and diff checking — all in your browser.

Key Takeaways

Validate and format JSON payloads with syntax error line pointers
Inspect and decode JWT tokens without exposing API credentials to third parties
Test complex Regular Expressions with real-time capture group visualization
Perform side-by-side text diffing with character-level change highlighting

1. Secure API Token Inspection

Pasting JSON Web Tokens (JWT) into unverified online web decoders risks leaking sensitive session tokens, user IDs, and claims to third-party server logs. Our JWT Decoder parses header, payload, and signatures completely in-memory, allowing safe debugging of expiration times and issuer claims.

2. Regular Expression Debugging Workflow

Use the Regex Tester with global (`g`), case-insensitive (`i`), and multiline (`m`) flags. The engine executes natively against JavaScript's V8 regex engine, rendering instant highlight matches, capturing groups, and execution benchmarks.

Recommended Tools for this Guide

JSON Formatter

Format, validate, and minify JSON

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JWT Decoder

Decode and inspect tokens safely

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Regex Tester

Test regular expressions with flags

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Diff Checker

Compare two blocks of code

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