API & Web Tools

API development and web debugging require a range of tools for testing endpoints, inspecting request/response headers, parsing user agents, and encoding URLs. Whether you're building a REST API, debugging WebSocket connections, or analyzing HTTP traffic, these tools help you understand and troubleshoot web communication at every layer.

Why Use These Tools?

Modern web applications depend on complex API interactions. Understanding HTTP headers, properly encoding URLs, and identifying client capabilities through user agent strings are essential skills. These tools give you instant insight into web communication without installing heavyweight desktop applications.

All api & web tools on Devkitr are completely free and run 100% in your browser. Your data never leaves your device — there are no server-side requests, no data logging, and no sign-up required.

Best Practices

• Always URL-encode query parameters to prevent injection vulnerabilities and broken requests
• Parse user agent strings server-side to serve appropriate content for different devices
• Test API endpoints with different HTTP methods and headers before integrating them into your app
• Use proper content-type headers (application/json, multipart/form-data) to ensure correct data handling

Privacy & Security

Every tool in this category processes your data entirely in your browser using JavaScript. We never transmit, store, or log any data you input. You can verify this by opening your browser's Developer Tools and monitoring the Network tab while using any tool — you'll see zero data requests related to your input.

Available Tools

• URL Encoder/Decoder – Encode or decode URLs and query parameters for safe transmission.
• User Agent Parser – Parse user agent strings to identify browser, OS, and device information.
• DNS Lookup Tool – Query DNS records — A, AAAA, CNAME, MX, TXT, NS, and SOA records for any domain.
• API Request Tester – Free online API tester — send HTTP requests and test REST APIs in your browser.
• WebSocket Tester – Connect to WebSocket endpoints, send/receive messages, and inspect real-time traffic.
• GraphQL Playground – Write and execute GraphQL queries with variables, headers, and response viewer.
• OpenAPI / Swagger Viewer – Free online Swagger editor and OpenAPI viewer — paste Swagger YAML/JSON and render interactive Swagger UI API documentation instantly.
• CORS Checker – Test if a URL returns proper CORS headers and diagnose cross-origin issues.
• Webhook Tester – Test webhooks online — generate a temporary webhook URL to capture, inspect, and debug incoming webhook payloads and requests.