JWT Generator
Generate JSON Web Tokens with multiple algorithm support and custom claims
api-toolsAPI Tools
API development utilities including JWT, curl, OpenAPI, and HTTP header tools
Available Tools
JWT Signature Verifier
Verify JWT token signatures with key validation and expiration checking
api-toolsCurl Command Builder
Build curl commands with a visual interface for HTTP requests
api-toolsCurl to Fetch Converter
Convert curl commands to JavaScript fetch() and vice versa
api-toolsOpenAPI Viewer
View and explore OpenAPI 3.x specifications with interactive documentation
api-toolsHTTP Header Inspector
Parse and analyze HTTP headers with explanations for common headers
api-toolsAbout API Tools
API development requires specialized tools for authentication, testing, and documentation. Our API tools streamline the entire API development workflow - from generating and verifying JWT tokens to building curl commands, converting between request formats, and exploring OpenAPI specifications.
Whether you're debugging authentication issues, converting curl commands to fetch calls, or inspecting HTTP headers, these tools provide instant results with complete privacy. All processing happens in your browser, so your API keys and sensitive data never leave your device.
Frequently Asked Questions
What API development tasks can these tools help with?
Our API tools cover authentication (JWT generation and verification), request building (curl command builder), format conversion (curl to fetch), API documentation (OpenAPI viewer), and debugging (HTTP header inspector). Together, they handle the most common API development and testing scenarios.
Are JWT tokens and API keys safe to use in these tools?
Yes. All tools process data entirely in your browser with no server communication. Your JWT tokens, API keys, and secrets never leave your device. This makes our tools safe for working with production credentials and sensitive authentication data.
What JWT algorithms are supported?
The JWT Generator and Verifier support both HMAC algorithms (HS256, HS384, HS512) and RSA algorithms (RS256, RS384, RS512). You can generate tokens with custom claims including expiration, issuer, audience, and subject fields.
Can I convert curl commands from API documentation?
Yes. The Curl to Fetch converter parses curl commands and generates equivalent JavaScript fetch() code. This is perfect for converting API documentation examples into code you can use in your application. It handles headers, authentication, request bodies, and different HTTP methods.
What is OpenAPI and why would I use the viewer?
OpenAPI (formerly Swagger) is a standard format for describing REST APIs. The OpenAPI Viewer parses these specifications and displays them as interactive documentation, showing all endpoints, parameters, request/response schemas, and authentication requirements. It uses Web Workers for large specifications to keep your browser responsive.