Start VS Code proxy troubleshooting by identifying the failing process: the editor, Marketplace, an extension, the CLI, or a command in the integrated terminal. They can use different configuration paths. Verify the failed operation itself after changing its setting; a successful terminal request does not prove Marketplace connectivity.
Reviewed: October 12, 2026. The installed Windows CLI reported VS Code 1.141.0, x64. We queried its version but did not run an editor network test, install an extension, or alter VS Code settings. Terminal observations below came from separate native command-line tests and are labeled accordingly.
Map the operation to its network owner
| Operation | What to investigate | Useful success observation |
|---|---|---|
| Marketplace search or install | Editor network path, proxy authentication and required hosts | That exact search or installation completes |
| Extension API request | Extension documentation and local/remote execution context | Extension request reaches its destination |
| code CLI operation | CLI-specific support for your version | The requested CLI operation completes |
| Integrated terminal curl/Python | Shell environment and the invoked client | Destination records the intended route |
| WSL or remote extension | Environment of the remote process | Observation from the remote client |
Record the error, operation, VS Code version, extension version and execution location. Avoid placing credentials or authorization headers in an issue report. An extension can have its own network stack or configuration; success elsewhere in the editor does not establish its route.
Configure the editor using its supported path
Current VS Code network documentation describes Chromium-based system proxy support, explicit proxy/PAC command-line controls, and legacy http.proxy settings for paths such as extensions and CLI. Start with the system policy or your organization’s supported configuration, then apply the documented control for the specific failing operation.
A scoped launch for an unauthenticated diagnostic endpoint can use the following syntax. The hostname is a placeholder, and the launch command was not executed as an editor network test here.
code --proxy-server="http://proxy.example:8080"Close and relaunch the intended test instance as required by your platform and version so an existing process does not obscure the configuration. Do not embed proxy passwords in command-line arguments or synchronized workspace settings. Record the previous configuration before changing anything, then restore it when the diagnostic ends.
Check Marketplace access independently
Search for a known extension first; then, if your policy allows it, test an installation. These are separate operations with potentially different destination hosts. Use the current official hostname list and proxy logs to identify the refused request rather than guessing a broad firewall exception. Keep installation within your organization’s extension policy. See Extension Marketplace documentation.
If search succeeds and an extension’s API fails, investigate that extension’s own execution environment and endpoint. A remote workspace can put part of the extension on another host. Read the extension host explanation and Remote Development FAQ when local and remote observations diverge.
Resolve authentication and certificate trust
The editor’s documented HTTP proxy support includes several authentication mechanisms; native authenticated SOCKS5 is a documented limitation. Do not assume an HTTPX SOCKS example transfers to the editor. For an authentication failure, confirm proxy policy and approved login flow. For a TLS failure, verify the issuer, hostname, clock and approved trust chain with your administrator. Keep certificate validation enabled.
Installing a corporate root certificate changes trust and should follow your organization’s process. It is a separate configuration decision from selecting a proxy host. Capture the error class and relevant certificate metadata without publishing private keys or credentials. Use the proxy error checklist for a sanitized record.
Test the integrated terminal as its own client
curl.exe --version
curl.exe --silent --show-error --fail --max-time 8 $env:CHECK_URLThis Windows example assumes CHECK_URL and any intended proxy variables were supplied in that terminal. It prints the endpoint body, so use a trusted response that is safe to inspect locally and redact before sharing. Query the executable version and compare the direct and proxied route from that executable. VS Code’s terminal documentation explains its shell context; the shell command remains a separate network client.
Our native Windows curl 8.21.0 tests honored both uppercase and lowercase HTTP proxy environment names; Linux curl 8.5.0 inside WSL used lowercase http_proxy and ignored uppercase HTTP_PROXY alone. These tests were performed outside the integrated terminal and do not establish its inherited environment. See the measured environment matrix and WSL2 routing to reproduce the relevant check in your own terminal.
Frequently asked questions
Why does curl work while Marketplace fails?
The two operations can use different processes, destinations, authentication and certificate stores. A successful curl request narrows the problem but does not validate the editor network path.
Should I put credentials in workspace settings?
Use your approved secret and proxy authentication mechanism. Workspace settings can be committed or synchronized; review their scope before adding any sensitive value.
Verify one client before increasing workload
Return to Proxy Setup and Developer Guides for adjacent clients. Use the proxy verification checklist to record a direct baseline and the destination’s observation. When that is repeatable, compare Mexela proxy locations against the actual destination and location requirements.
Download the developer examples
Download the developer examples ZIP for the locally tested Python clients, environment checks, CI route-check files and native PHP cURL helper. The n8n workflow is a separate illustrative reference: it was not imported or executed in n8n. Read the included README for runtime versions, setup and the limits of each check.
ZIP SHA-256: 3a43f7d1e6cbb9b2917dbcf88aaa8fe1a2733c33326187cb89c9a9119aad3e20. Keep real proxy credentials and destination secrets in your approved secret store; they are absent from this archive. Start with one approved destination and compare its observation with a direct baseline.