Resonance

A lightweight, local-first, open-source alternative to Postman and Insomnia. No account. No cloud sync. No telemetry. Your collections are plain JSON files on your disk.

Installation · Features · Screenshots · Documentation · Scripting · Contributing

 

Why Resonance?

• Local-first, zero-account — everything works offline, forever. Collections, environments, history, and settings live as human-readable JSON files that you can version, diff, and share with git.
• Genuinely lightweight — built with Tauri and a Rust backend: ~15 MB bundle size, ~50 MB memory footprint.
• Every protocol you need — REST, GraphQL (incl. subscriptions), gRPC (with server reflection), WebSocket, Server-Sent Events, and MQTT in one client.
• Secrets stay secret — credentials and secret variables are stored in your OS keychain (GNOME Keyring / KWallet, macOS Keychain, Windows Credential Manager), never in the collection files you commit.
• Batteries included — OpenAPI & Postman import, mock server, pre-request/test scripting, collection runner, code generation in 9 languages, mTLS.

Features

Protocols

• REST/HTTP — HTTP/1.1 and HTTP/2, all body modes (JSON, form data, URL-encoded, plain text, binary files, multipart file uploads), detailed timing breakdown (DNS, TCP, TLS, TTFB, download), cookie display, configurable timeouts
• GraphQL — dedicated query and variables editors with syntax highlighting, auto-format, and live subscriptions over WebSocket (graphql-transport-ws)
• gRPC — server reflection (v1/v1alpha) with automatic service discovery, all four RPC kinds (unary, server-, client-, and bidirectional streaming), TLS/mTLS options, metadata and trailers display
• WebSocket — persistent connections per tab, handshake headers, transcript-style message display
• Server-Sent Events — automatic reconnection honoring retry, Last-Event-ID resumption, live connection lifecycle status
• MQTT — plaintext and TLS brokers, topic subscribe/publish with wildcards, QoS 0/1/2, retain flag, live connection status

Import, Export & Mocking

• OpenAPI 3.0 import (YAML/JSON) with schema-based example generation, Postman import (v2.0/v2.1 collections and environments), OpenAPI export
• Code generation in 9 languages — cURL, Python, JavaScript (Fetch/Axios), Node.js, Go, PHP, Ruby, Java
• Built-in mock server — generates responses from OpenAPI schemas, custom bodies and delays per endpoint, request logging

Automation & Testing

• Pre-request and test scripts — sandboxed JavaScript (Boa Engine) with request mutation, expect() assertions, environment access, and sendRequest() for request chaining (full scripting docs)
• Collection runner — batch execution with ordering, variable chaining, stop-on-error, delays, and saved configurations
• Environments & variables — {{ variable }} templating, dynamic variables ({{$uuid}}, {{$timestamp}}, random data), quick environment switching, import/export

Security

• Auth methods — Bearer, Basic, API Key, OAuth 2.0, Digest, AWS Signature v4 — configurable at request, folder, or collection level
• Client certificates (mTLS) — per-host PEM certificates with custom CA trust
• Keychain-backed secrets — literal credentials and secret variables are encrypted at rest in the OS credential store and never written to the git-friendly collection files
• Proxy support — HTTP/HTTPS/SOCKS with authentication and bypass lists

Workflow & UX

• Workspace tabs with independent, persistent state; request history with search and replay
• Keyboard shortcuts for everything, platform-aware (Ctrl/⌘)
• 4 themes (light, dark, system, OLED black) with 9 accent colors; 6 languages (English, German, Spanish, French, Italian, Brazilian Portuguese)
• Auto-update for AppImage and direct downloads; package-manager installs defer to their own update mechanism

See the documentation site for detailed guides on every feature.

Installation

Linux

Flathub

flatpak install flathub io.github.db_mobile.resonance

Snap

snap install db-mobile-resonance

To store secrets in the OS keychain (encryption at rest), connect the password-manager interface:

snap connect db-mobile-resonance:password-manager-service

Without this connection the strict snap cannot reach the Secret Service (GNOME Keyring / KWallet), and secrets fall back to unencrypted local storage.

AUR (Arch Linux)

yay -S resonance-bin

AppImage / .deb — download from the latest release.

macOS

brew tap db-mobile/resonance
brew install --cask resonance

Or download the .dmg from the latest release.

Windows

winget install DBMobile.Resonance

Or download the .exe installer from the latest release.

From Source

Requires Node.js v22+, Rust (stable), and Tauri's platform dependencies (Linux: sudo apt install libwebkit2gtk-4.1-dev build-essential curl wget file libssl-dev libayatana-appindicator3-dev librsvg2-dev; macOS: xcode-select --install; Windows: MSVC Build Tools).

git clone https://github.com/db-mobile/resonance.git
cd resonance
npm install
npm run dev          # development mode with hot reload
npm run build:tauri  # production build → src-tauri/target/release/bundle/

Screenshots

Environment management	Mock server

Settings

Documentation

User documentation lives on the Resonance website — guides for every protocol, the mock server, collection runner, scripting, and more.

• Documentation site — environments, variables, auth, mTLS, mock server, GraphQL, per-protocol guides
• Scripting Reference — pre-request/test script API with examples (also on the website)
• Architecture — project structure and technology stack for contributors

Roadmap

• Response comparison and diff view
• Git integration for collections (versioning & sync)
• Team collaboration features

Completed milestones

• OpenAPI 3.0 import with schema-based generation
• Postman collection import (v2.0 & v2.1)
• Postman environment import
• Multi-language code generation (9 languages)
• Workspace tabs for concurrent requests
• Performance metrics and timing breakdown
• Cookie management and display
• Proxy support with authentication (HTTP/HTTPS/SOCKS)
• Variable templating system with environment support
• Dynamic variables (UUID, timestamps, random values)
• Multi-theme support (4 themes with 9 accent colors)
• Internationalization (6 languages)
• Authentication support (Bearer, Basic, API Key, OAuth2, Digest)
• Client certificates / mTLS with per-host configuration and custom CA trust
• Request history with search and replay
• Environment management (Dev, Staging, Production, custom)
• Keyboard shortcuts for all major actions
• Mock server with custom responses and delays
• Collection export (OpenAPI format)
• Pre-request and test scripts with JavaScript execution (Boa Engine)
• Automated testing framework with rich assertion API
• Request chaining with environment variable integration
• GraphQL support with dedicated query and variables editors
• GraphQL subscriptions over WebSocket (graphql-transport-ws)
• Tauri v2 migration for smaller bundle and better performance
• gRPC support with server reflection and all four RPC kinds (unary, server/client/bidirectional streaming)
• WebSocket support with native backend transport and handshake headers
• Server-Sent Events (SSE) support with automatic reconnection and Last-Event-ID resumption
• MQTT support with topic subscribe/publish, QoS levels, retain, and TLS brokers
• Collection runner for batch request execution with variable chaining
• File uploads: multipart form-data file parts and binary request bodies

Contributing

Contributions are welcome!

1. Fork the repository and create a feature branch: git checkout -b feature/amazing-feature
2. Follow the existing patterns and conventions (see Architecture)
3. Run npm run lint and npm test before committing
4. Open a Pull Request

Found a bug or have a feature request? Open an issue — please check existing issues first and include as much detail as possible.

License

This project is licensed under the MIT License — see the LICENSE file for details.