Resonance

Resonance is a local-first, zero-account API client application designed to provide an excellent user experience for testing and interacting with web services. It offers a modern and intuitive interface for developers with powerful features for API development and testing.

Key Features:

• Import collections from OpenAPI 3.0 specifications and Postman collections
• Environment management with variable templating for different deployment contexts
• Multiple authentication methods including Bearer tokens, Basic Auth, API keys, OAuth 2.0, Digest and AWS Signature authentication
• Generate code snippets in 9 languages: cURL, Python, JavaScript (Fetch), JavaScript (Axios), Node.js, Go, PHP, Ruby, and Java
• GraphQL support with dedicated query editor and syntax highlighting
• gRPC support for exploring and testing gRPC services
• WebSocket support with persistent connections and handshake headers
• Server-Sent Events (SSE) support with automatic reconnection
• MQTT support with topic subscribe/publish, QoS levels, and TLS brokers
• Collection runner for batch request execution with variable chaining between requests
• Built-in mock server for testing without a backend, with custom responses and configurable delays
• Workspace tabs for managing multiple concurrent requests with independent state
• Request history with search and replay capability for easy debugging
• Performance metrics showing detailed timing breakdown including DNS, TCP, TLS, and download times
• Cookie management with full attribute display
• HTTP proxy support with authentication and bypass lists
• Protocol version control supporting HTTP/1.1, HTTP/2, and HTTP/3
• Comprehensive keyboard shortcuts for efficient workflow
• Four theme options: light, dark, system-adaptive, and black (OLED)
• Available in English, German, Spanish, French, Italian and Portuguese (BR)