Dev Proxy v2.1.0 Release Features

Configuration Hot Reload

Dev Proxy v2.1.0 now includes an automatic configuration hot reload feature. The tool watches the configuration file and automatically restarts whenever changes are saved. This functionality replaces the previous requirement to manually stop and restart the proxy when making adjustments, such as modifying failure rates, adding plugins, or changing URL patterns. This feature addresses user feedback dating back to April 2023 and is designed to maintain development flow during iterative testing.

Stdio Traffic Proxying

Support has been added for intercepting, inspecting, and mocking traffic sent via stdin, stdout, and stderr. This feature targets modern AI development workflows, particularly those involving Model Context Protocol (MCP) servers. Users can wrap executables using the command devproxy stdio npx my-mcp-server . This capability allows developers to inspect messages in the Chrome DevTools Network tab, mock responses using the MockStdioResponsePlugin, and simulate latency. It also supports placeholders like @stdin.body.id in mock responses.

Command-Line Port Configuration

A new command-line option, --api-port , allows users to configure the API port directly without altering the configuration file. This is useful for running multiple Dev Proxy instances or when the default port 8897 is required for other applications. Users can execute commands such as devproxy --api-port 9000 to set the port at runtime.

Latency and Plugin Improvements

The LatencyPlugin schema has been updated to remove the artificial limit of 10,000 milliseconds (10 seconds) on the maxMs property. This allows for the simulation of delays of any duration, facilitating testing for timeout handling and slow network conditions. Additionally, CORS support has been enabled for the Dev Proxy web API.

Bug Fixes and Enhancements

Several bug fixes are included in this release. The GenericRandomErrorPlugin now correctly matches all HTTP methods (including POST, PUT, and DELETE) rather than defaulting to GET only. The MockResponsePlugin has been updated to prevent spurious JSON parsing warnings when handling form data or non-JSON content types. Furthermore, changes to CRUD API data files now take effect immediately via hot reload.

Dev Proxy Toolkit 1.12.0

The Dev Proxy Toolkit extension for Visual Studio Code has been updated to version 1.12.0. New features include a devProxyPath setting for specifying custom installation paths and smarter configuration validation against the Dev Proxy schema. The update provides enhanced diagnostics with precise highlighting and documentation links, as well as quick fixes for adding missing plugin sections, updating schema versions, and removing unknown properties.