The latest articles on DEV Community by pepe (@pepe8173bbb). https://dev.to/pepe8173bbb https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4085950%2F48fb5204-7be5-4f13-843a-c4cdd52ada79.jpg https://dev.to/pepe8173bbb en pepe Thu, 20 Aug 2026 19:47:31 +0000 https://dev.to/pepe8173bbb/i-built-devtolkit-a-privacy-first-100-offline-swiss-army-knife-for-developers-33gl https://dev.to/pepe8173bbb/i-built-devtolkit-a-privacy-first-100-offline-swiss-army-knife-for-developers-33gl <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fp77besfuxz05k1bgcnh8.png" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fp77besfuxz05k1bgcnh8.png" alt="ui demo" width="800" height="549"></a></p> <h2> The Problem </h2> <p>We've all been there. You're debugging an API response, need to format some JSON, or quickly convert a YAML config file. You open a random online tool, paste your data, and... <em>boom</em>.</p> <p>You just sent your production API keys, database credentials, or customer PII to an unknown third-party server.</p> <p>I got tired of that risk. I also got tired of having 15 tabs open just to format JSON, test a regex, compare two files, or generate a hash.</p> <h2> The Solution: DevTolkit </h2> <p>I built <strong>DevTolkit</strong> — a clean, modern, <strong>offline-first</strong> Swiss Army knife for developers. </p> <p><strong>Everything runs 100% in your browser. Zero data ever leaves your machine.</strong></p> <h3> 🔧 What's inside? </h3> <div class="table-wrapper-paragraph"><table> <thead> <tr> <th>Tool</th> <th>What it does</th> </tr> </thead> <tbody> <tr> <td><strong>JSON Formatter</strong></td> <td>Validate, format, and minify JSON with syntax highlighting</td> </tr> <tr> <td><strong>YAML ↔ JSON</strong></td> <td>Convert YAML to JSON and vice versa (perfect for K8s configs)</td> </tr> <tr> <td><strong>CSV Converter</strong></td> <td>Convert CSV to JSON and JSON to CSV</td> </tr> <tr> <td><strong>Base64</strong></td> <td>Encode and decode Base64 strings</td> </tr> <tr> <td><strong>URL Encoder</strong></td> <td>Encode/decode URL parameters</td> </tr> <tr> <td><strong>Crypto Hashes</strong></td> <td>Generate MD5, SHA-1, SHA-256, SHA-512 hashes</td> </tr> <tr> <td><strong>Visual Diff</strong></td> <td>Compare two texts side-by-side with color-coded differences</td> </tr> <tr> <td><strong>JSONPath</strong></td> <td>Query and test JSONPath expressions on your JSON data</td> </tr> <tr> <td><strong>Regex Tester</strong></td> <td>Test regular expressions with real-time matches and groups</td> </tr> <tr> <td><strong>Dark / Light Themes</strong></td> <td>Multiple themes and accent colors for your eyes</td> </tr> </tbody> </table></div> <h3> 🚀 Why it's different </h3> <ul> <li> <strong>🔒 Privacy-first</strong> – Your data never touches a server. Not even mine.</li> <li> <strong>📡 Works offline</strong> – It's a Progressive Web App (PWA). Install it and use it anywhere.</li> <li> <strong>🎨 Modern UX</strong> – No clutter, no ads, no sign-ups. Just open and work.</li> <li> <strong>💻 Open Source</strong> – All code is on GitHub. Audit it, fork it, contribute.</li> </ul> <h3> 🛠️ Tech Stack </h3> <ul> <li>Vanilla JavaScript (no frameworks, no bloat)</li> <li>CSS3 with CSS variables for theming</li> <li>Service Workers for offline support</li> <li>Web Workers for heavy processing (so your UI never freezes)</li> </ul> <h2> 🙋 Who is this for? </h2> <ul> <li> <strong>Backend / DevOps engineers</strong> – Safe handling of configs and secrets.</li> <li> <strong>Frontend developers</strong> – Quick API debugging and JSON manipulation.</li> <li> <strong>Students / Juniors</strong> – Learn about JSON, YAML, regex, and hashing with a visual tool.</li> <li> <strong>Freelancers</strong> – A reliable toolbox when you're offline at a coffee shop.</li> </ul> <h2> 🔗 Try it now </h2> <p>👉 <strong>Live demo:</strong> <a href="https://pepe8173bbb.github.io/DevTolkit/" rel="noopener noreferrer">https://pepe8173bbb.github.io/DevTolkit/</a></p> <p>👉 <strong>Source code:</strong> <a href="https://github.com/pepe8173bbb/DevTolkit" rel="noopener noreferrer">https://github.com/pepe8173bbb/DevTolkit</a></p> <h2> 🤔 What's next? </h2> <p>I'm actively working on:</p> <ul> <li>Support for larger files (streaming)</li> <li>JWT Debugger</li> <li>SQL Formatter</li> </ul> <h2> 💬 I'd love your feedback </h2> <ul> <li>What feature do you use the most?</li> <li>What tool am I missing?</li> <li>Does the Diff visualizer feel intuitive?</li> </ul> <p>Drop a comment below or open an issue on GitHub. If you like it, please give it a ⭐ star — it really helps!</p> <p>Thanks for reading! 🙌</p> webdev javascript opensource devtools