Adding a Timestamp Query Parameter with Hoppscotch Pre‑request Scripts

Desired outcome

You want every request you send from Hoppscotch to include a unique timestamp query parameter (e.g., ?ts=1728394560000) so that caching layers or downstream services treat each call as distinct.

Prerequisites

• Hoppscotch installed (web app, desktop client, or self‑hosted instance) and accessible.
• A request already created (e.g., a GET to https://httpbin.org/anything) that you will modify.
• Basic familiarity with the Hoppscotch UI: request editor, tabs, and environment variables panel.

Focused procedure

1. Open the request you wish to edit. In the request editor, locate the tabs beneath the main URL/body area and click the Pre‑request Script tab.
2. In the script editor, paste the following JavaScript code. This script generates a millisecond‑precision timestamp, stores it in an environment variable named timestamp, and then adds it as a query parameter to the request URL.

   // Generate timestamp
   const ts = Date.now();
   // Save to environment (persists until cleared)
   pm.environment.set('timestamp', ts);
   // Add as query parameter
   pm.request.url.addQueryParam({ key: 'ts', value: ts.toString() });
   

3. Click the Save button (or press Ctrl+S) to store the script with the request.
4. Optional: Verify that the environment variable is set by opening the Environment sidebar, locating the current environment, and confirming that timestamp appears with a numeric value.
5. Send the request using the Send button. Before the request leaves Hoppscotch, the preview pane (usually below the editor) should show the URL with the added ?ts=… parameter.
6. After the response arrives, open the Console panel at the bottom of the UI. Ensure there are no red error messages; any console output you placed in the script (e.g., console.log('timestamp set', ts)) will appear here.

Expected checks

• Request preview: URL contains ?ts=<numeric value> where the value matches the millisecond timestamp generated by Date.now().
• Environment panel: variable timestamp holds the same numeric value.
• Console: no uncaught exceptions; if you added a console.log statement, you see its output.
• Response body (from httpbin): the args object includes the ts key with the same value.

Recovery options

If you discover that the timestamp is causing unintended side effects (e.g., persisting across unrelated requests), you can:

1. Clear the environment variable manually: open the Environment sidebar, hover over timestamp, and click the × button to delete it.
2. Disable the pre‑request script temporarily: return to the Pre‑request Script tab, comment out or delete the pm.environment.set line, then save.
3. Reset the environment entirely: from the Environment dropdown, choose Clear to remove all variables, then re‑add any you need.

Limitations and practical verification

The Hoppscotch sandbox provides a limited set of globals (console, setTimeout, fetch when enabled). Avoid importing large external libraries directly; if you need complex logic, bundle it into a single script or use the built‑in fetch to retrieve small JSON payloads.

To verify that the script runs on every request, send the same request twice in quick succession and compare the two ts values in the console or response; they should differ by a few milliseconds.