Zorvik is a free, open-source desktop application, version 0.2.1, built publicly by the LibreGuild community and licensed under MIT or Apache-2.0. It is aimed at developers who need to build, test, mock, and load test APIs over multiple network protocols, as well as people who need to test and mock the MCP servers used by AI agents. The application is local-first, supports Windows, macOS, and Linux; there are no paid plans, no accounts, no cloud sync, and no tracking, and it can work offline, with the only self-initiated connection being to GitHub to check for updates.
Purpose and main capabilities Zorvik combines multiple protocol clients, testing, mocking, load testing, and network tools into one workbench, replacing multiple tools with a single application, and sharing the same set of files and engine. Supported protocols include HTTP, GraphQL, gRPC, WebSocket, Socket.IO, SSE, MQTT, TCP, UDP, and DNS. GraphQL supports subscriptions; Socket.IO supports versions 3 and 4; Server-Sent Events are supported; DNS supports over UDP, TCP, TLS, and HTTPS. Every request shows where the time went, the certificate that responded, the redirect path, and the headers that actually left the local machine.
MCP testing and mocking AI applications and agents access tools through MCP servers, and models trust the descriptions, schemas, and responses of those tools. Zorvik can show what agents actually see: connect to any MCP server, call its tools with your own parameters, observe every JSON-RPC message, and verify responses in CI. It supports Streamable HTTP, HTTP+SSE, and stdio programs such as npx, supports authentication and OAuth 2.0, and allows viewing tools, schemas, resources, templates, and prompts. When building agents, you can provide an MCP server where you control the tools, failures, and latency.
How to use it In the desktop application, each protocol uses a unified editor, including parameters, authentication, scripts, and responses with timing, TLS, and real request headers. Test scripts are written in an English-like way, are compatible with Postman scripts, and imported collections can run as-is. You can create routes with parameters and templates, delays, failures, CORS, and forwarding rules. Load tests can run on a laptop, support virtual users or arrival rates, and thresholds such as "p95 below 200 milliseconds."Built-in network inspection tools, including a TLS inspector, DNS lookup, port check, ping, HTTP/3 check, and encoders such as Base64, JWT, and hashes. Requests imported from OpenAPI documents are contract-checked against the document on every send, and existing edits are preserved when updating to a new version.
Coding agent integration Coding agents such as Claude Code, Codex, Gemini CLI, and Cursor can connect with a single command and drive Zorvik via MCP. Agents can turn APIs in code into requests, send requests, write tests, run collections, build and start mock servers, run load tests, and read traffic, all observable in Zorvik. 38 tools are provided, covering requests, environments, runs, servers, load tests, history, and code export. Risky operations such as deletion, load testing, servers, and external hosts require user confirmation; secrets are masked in what agents can see.
Command line and pipelines The command line ships with the application. zorvik run can run collections and folders and data files, generate JUnit and JSON reports, and exits with code 1 when tests fail; zorvik load runs saved load tests and their thresholds and generates an HTML report; zorvik serve runs saved mocks or servers headlessly, with traffic output as JSON lines; zorvik mcp is the MCP server that AI agents start to collaborate with Zorvik.
Workspace and security A workspace is a folder containing readable YAML that can be committed, reviewed in pull requests, and shared, with Git serving as the means for synchronization, history, and review. Secret values, cookies, and tokens are kept locally and are not written to workspace files. System or manual proxies, the operating system certificate store, custom CAs, and client certificates are supported.
Learning features The app includes a Training Bootcamp course, from "what is a network" to mocking and load testing, with short illustrated readings and labs in a real workbench. Practice servers start locally on 127.0.0.1, and lab guides are checked off automatically when steps are correct. Progressive hints from a prompt to specific clicks are provided, along with a "do it for me" option, including experience points, levels, streaks, and a Zorvik Bootcamp graduation certificate, and it can run offline.
Downloads and platforms Installers are provided (Windows 10/11, no administrator privileges required, 28.2 MB), a portable version (extract and run, 39.0 MB), a macOS disk image (macOS 11+, Apple silicon and Intel, 70.9 MB), .deb (Ubuntu 22.04+, Debian 12+, 38.0 MB), .rpm (Fedora, RHEL, openSUSE, 38.0 MB), AppImage (any x86-64 Linux, 109 MB), and a command-line-only standalone version for CI machines, servers, and containers. The app reads the latest release from the GitHub releases page to update itself and does not send any user information.
Limitations The material does not provide information about mobile support, scale limits for concurrent load testing, details of the supported MCP protocol version, whether it is compatible with other testing tool formats (besides Postman collections), or specific minimum system requirements. The builds are not yet code-signed: on Windows you need to choose "More info → Run anyway," and on macOS you need to allow it in "System Settings → Privacy & Security." For the latest changes, you can try nightly builds or build from source.
