Hoppscotch Browser Extension and Proxy Agent: Environment Variable Resolution Consistency

Variable Resolution Consistency

Environment variable substitution in Hoppscotch is handled at the application layer (the frontend) before the request is dispatched. Because the substitution occurs prior to the request being handed off to an interceptor, the resolution process is identical regardless of whether you use the browser extension or the proxy agent.

Mechanism of Action

The browser extension and the proxy agent function as transport mechanisms designed to bypass Cross-Origin Resource Sharing (CORS) restrictions. They operate as follows:

• Browser Extension: Uses elevated browser privileges to make requests that ignore CORS headers.
• Proxy Agent: Routes the request through a separate server (often a Docker container) to strip or modify CORS headers before the request reaches the target API.

Neither the extension nor the proxy agent performs independent variable resolution. The Hoppscotch core logic injects the environment values into the request payload first; the interceptor then simply transmits the already-resolved request.

Potential Edge Cases and Divergence

While variable resolution is consistent, you may encounter behaviors that appear to be resolution failures but are actually network-layer issues:

• Proxy Reachability: In self-hosted Docker deployments, if the proxy agent is unreachable or misconfigured, the request will fail. This may be mistaken for a variable resolution error if the URL itself contains a variable that points to an incorrect internal Docker network address.
• Header Manipulation: Some proxy configurations may strip or modify specific headers. If a variable is used to populate a sensitive header, the proxy agent's configuration (rather than the resolution logic) could be the cause of the missing value.

Verification Steps

To verify that variables are resolving consistently in your environment, perform the following test:

1. Create an environment variable (e.g., test_var = "verification_success").
2. Add this variable to a custom request header: X-Test-Header: {{test_var}}.
3. Send the request using the Browser Extension and verify the header value in the browser's Network tab.
4. Switch to the Proxy Agent and verify the same header value arrives at the destination server.

Diagnostic Note: If you are experiencing inconsistent behavior, please specify if the failure occurs specifically with dynamic variables (like timestamps) or static environment variables.