The Dev Proxy team has released Dev Proxy version 2.1, introducing new features aimed at improving developer productivity and simplifying local testing workflows. This release focuses on faster iteration, better support for modern development tools, and several refinements across the proxy and its related tooling.
One of the main additions in Dev Proxy v2.1 is configuration hot reload. The proxy now watches the configuration file and automatically restarts when changes are saved. This removes the need for manual restarts during development. According to the maintainers, this feature addresses a long-standing request from the community and is intended to make it easier to adjust settings such as mock responses, error rates, plugins, or URL patterns while keeping the development flow uninterrupted.
Another key feature in this release is stdio traffic proxying. Dev Proxy can now intercept, inspect, and mock standard input, output, and error streams. This capability is designed to support tools that communicate over stdio, including Model Context Protocol (MCP) servers and similar utilities. By wrapping an executable with Dev Proxy, developers can view stdio traffic in familiar browser tooling, simulate latency, and return mocked responses. This expands the scope of Dev Proxy beyond HTTP-based scenarios and enables testing and debugging of a wider range of applications.
Dev Proxy v2.1 also introduces a new command-line option for configuring the API port. As explained, developers can now set the port directly when starting the proxy, which simplifies running multiple instances or avoiding port conflicts. In addition, the LatencyPlugin has been updated to allow delays longer than ten seconds, making it possible to test long-running requests and timeout handling more realistically. The web API now supports cross-origin requests, enabling browser-based tools to interact with the proxy without CORS issues.
The release includes several bug fixes and smaller improvements. These address issues in environment variable handling, API key validation, HTTP method matching, content type processing, and data file reload behavior.
Alongside the core proxy, Dev Proxy Toolkit version 1.12 is also available, bringing better configuration validation, clearer diagnostics, improved quick fixes, and enhanced plugin support in Visual Studio Code.
As a side note, Dev Proxy version 2.0 was released earlier with a major version update due to small but important breaking changes. That release introduced support for .NET 10, improved AI telemetry with better token tracking, and adjustments to date formatting and telemetry behavior to improve accuracy and reliability. It also included general fixes and refinements to API simulation behavior.
With version 2.1, the Dev Proxy team highlights faster iteration, improved support for AI and stdio-based tools, and a cleaner overall development experience. For interested readers, full release notes and detailed change logs are available in the official documentation and project repositories.
