Developer Tools
Free browser-based utilities for encoding, formatting, generating, and debugging. No sign-up, no data sent to servers.
Developer tools — what they do and when to use them
JSON is the dominant data format on the web, used in REST APIs, configuration files, and data storage. It looks simple but has strict rules that catch developers out: all keys must be double-quoted strings, trailing commas after the last item are not allowed, and values can only be strings, numbers, booleans, null, arrays, or objects. The JSON formatter uses the native JSON.parse() API to validate your input and JSON.stringify() to re-format it with consistent indentation, showing the exact line and character of any error. Base64 encoding is not encryption — it is a binary-to-text encoding scheme used to safely transmit binary data (images, files, tokens) through text-only channels like HTTP headers and HTML. The btoa() and atob() browser APIs handle it natively. UUID v4 identifiers use crypto.randomUUID() — a cryptographically secure source of randomness — to generate 128-bit identifiers with 5.3 × 10^36 possible values, making collisions statistically impossible in any realistic system.
URL encoding converts characters that have special meaning in URLs (spaces, &, =, ?) into percent-encoded sequences using encodeURIComponent(). This is required when passing user input as query parameters to prevent ambiguity in URL parsing. The regex tester lets you write and test regular expressions against sample text, with real-time match highlighting — essential for validating email patterns, parsing structured strings, or writing search-and-replace rules. JWT (JSON Web Token) is a three-part base64-encoded structure: header, payload, and signature. The JWT decoder base64-decodes the first two parts to reveal the algorithm and claims without verifying the signature, which is useful for debugging authentication flows. The cron parser translates cryptic five-field cron expressions (minute, hour, day, month, weekday) into plain-English descriptions, making it easy to verify scheduled job timings before deploying.
All tools run entirely in your browser — no data is sent to any server. Browse all free tools at toolsmithpro.com.
About these developer tools
All tools run entirely in your browser using native Web APIs: JSON.parse for formatting, btoa/atob for Base64, crypto.randomUUID() for UUIDs, encodeURIComponent for URL encoding, the RegExp constructor for regex testing, and base64 decoding for JWT inspection. Nothing is sent to a server. Developer tools are the highest-CPM category on the site — bookmark this page.