Everyday developer problems solved in your browser
DevSandbox is a unified suite of fast, lightweight developer utilities designed for daily programming workflows. Every utility is engineered to execute client-side using browser-native APIs like WebCrypto, TextEncoder, and Intl, with zero server uploads.
Why client-side processing matters
In November 2025, watchTowr Labs disclosed that popular online formatters had exposed more than 80,000 saved pastes (over 5 GB of private data) through unauthenticated public endpoints. The leak included live AWS root credentials, Active Directory passwords, private API keys, and corporate database connection strings.
DevSandbox eliminates this threat entirely: the browser's Content-Security-Policy (CSP) forbids the page from making unauthorized outbound network requests. You can verify this anytime by opening your browser's Developer Tools and inspecting the Network tab.
Tool categories
| Category | Included Utilities | Primary Use Cases |
|---|---|---|
| Data & JSON | JSON Formatter, JSONPath Tester, YAML ↔ JSON Converter | API debugging, formatting payloads, query evaluation, configuration management. |
| Encoding & Crypto | Base64 & Base64URL, URL Encoder/Decoder, Hex Converter | Token debugging, query parameter inspection, data serialization. |
| Time & Scheduling | Unix Timestamp Converter, Cron Expression Builder | Epoch time inspection, scheduling validation, countdowns, timezone math. |
| Code & Text | Diff Checker, Regex Tester & Explainer | Patience file comparison, pattern debugging, git patch generation. |
| Security & Tokens | JWT Decoder & Verifier, Secret Scanner | Claims inspection, expiration checks, signature verification with WebCrypto. |
How to use the smart paste entry point
- Paste any developer snippet directly into the box at the top of the homepage.
- DevSandbox's deterministic detector immediately classifies the format (JSON, JWT, URL, Unix timestamp, Base64, Cron, or Regex).
- Click the suggested action chip to jump straight into the specialized tool with your data preloaded via a private URL fragment.
Frequently asked questions
What is DevSandbox?
DevSandbox is a fast, privacy-first collection of developer utilities that execute entirely client-side in your browser. Tools include JSON formatting, JSONPath evaluation, YAML-JSON conversion, Base64 encoding, URL parsing, timestamp conversion, cron building, regex testing, diff checking, and JWT verification.
Is my data uploaded to any server?
No. All tools execute locally in your web browser using JavaScript and browser-native WebCrypto and TextEncoder APIs. The strict Content-Security-Policy prohibits unauthorized outbound network requests.
Do I need to sign up or create an account?
No account, signup, or API key is required. You open any tool and start working immediately with zero tracking.