dev-sidecar

dev-sidecar (often shortened to "ds" in its own README) is a desktop tool aimed at Chinese developers who struggle to reach GitHub and other developer resources because their connection to those sites is slow, unstable, or sometimes blocked outright. The repository's description, in Chinese, lists the problems it tries to solve: GitHub being unreachable, git clone being slow, GitHub release downloads being slow, and Stack Overflow being slow. It is presented not as a VPN but as a "sidecar" — a helper tool that sits next to your normal setup and quietly accelerates traffic to a handful of developer-focused destinations. The way it works is that, once installed and started, dev-sidecar sets itself as the system's local HTTPS proxy. It then applies a few techniques per destination: DNS preference (asking DNS for the IP list for a domain and probing each one to pick the fastest), request interception (forwarding GitHub clone, release, source-zip, raw, blame, gist, and avatar traffic through configurable mirror sites with automatic failover to a backup when one mirror is slow or down), an SNI-based trick to connect directly to GitHub (credited in the README to the FastGithub project), Stack Overflow acceleration (proxying ajax.googleapis.com to a CDN and speeding up the reCAPTCHA images), and an npm acceleration mode that switches between the official and the Taobao npm registries. Because it intercepts HTTPS, it generates a local root certificate that the user installs once. Two modes are provided: a Safe mode that only does DNS preference and speed testing without installing a certificate, and a Default mode that turns on the full interception set. You would use this if you are a developer in mainland China and find that GitHub repositories, releases, gists, README images, or Stack Overflow assets either fail to load or are too slow to be usable. The application is built with Electron and is available as a desktop installer for Windows, macOS, and Debian/Ubuntu Linux from the GitHub releases page.