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)

Resonance

Install on Linux