💡 "Postman Can’t Automatically Clear/Reset Variables"? Here’s How It Can!

[danny-dainton]

Background: Community Feedback
This post was inspired by a comment from @abdulkabirsultan in a previous weekly challenge, who pointed out that environment variables can linger after runs and cause test issues.

See the community feedback and problem context

@abdulkabirsultan

Automatically Clear/Reset Environment Variables After Test Runs

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The Problem:
Every Postman user who runs collections regularly faces the same hidden productivity killer: environment variable pollution. After each test run, variables like userId, authToken, orderId, etc. persist in the environment, creating a cascade of issues that compound over time.

Why This Matters More Than You Think:

• Silent Failures: Old variables cause mysterious test failures and false positives that can waste hours of debugging
• Team Friction: One developer’s leftover variables confuse teammates and break shared environments
• Cognitive Overhead: The constant mental burden of remembering to manually clean up after every run
• Scales Badly: The problem gets exponentially worse in CI/CD pipelines and automated testing

The Solution:
Add a “Clean Environment After Run” option that automatically:

• Resets specified variables to default values
• Clears all variables created during the collection run
• Logs cleanup actions for traceability
• Works seamlessly with Collection Runner and Newman

Impact:
This isn’t just a nice-to-have—it’s infrastructure that makes Postman more reliable for everyone. While other features might speed up specific workflows, this prevents the kind of silent breakage that undermines trust in your testing process.

Every Postman user who’s ever wondered “why is this test suddenly failing?” or spent time hunting down stale variables will immediately appreciate this improvement.

Watch the Fix in Action
Here’s a 5 minute walkthrough of the simple script I use to automatically reset and clean up environment variables, no more manual clearing after every run. This approach has made my workflow far more efficient and has helped me collaborate more effectively with my teammates by keeping shared environments clean and consistent.

Package Library Clean Up Script:

const cleanupVars = (options = {}) => {
    const {
        scope = "environment",   // "environment", "collectionVariables", or "globals"
        exclude = [],            // Array of variable names to KEEP
        log = true               // Whether to log actions
    } = options;

    // Validate scope
    const validScopes = ["environment", "collectionVariables", "globals"];
    if (!validScopes.includes(scope)) {
        console.error(`Invalid scope: ${scope}. Must be one of ${validScopes.join(", ")}.`);
        return;
    }

    // Select the variable scope
    const variableScope = pm[scope];
    const allVars = Object.keys(variableScope.toObject());

    // Loop through and remove all not in exclude list
    for (const varName of allVars) {
        if (!exclude.includes(varName)) {
            variableScope.unset(varName);
            if (log) console.log(`🧹 Cleared ${scope} variable: ${varName}`);
        }
    }

    if (log) {
        console.log(
            `✅ Cleanup complete for ${scope} variables. Preserved: [${exclude.join(", ") || "none"}]`
        );
    }
}

module.exports = { cleanupVars }

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Did this fix help you out? Tell us in the comments!

And if there’s another Postman topic you’d love a quick walk through on, let us know

[edhammerbeck]

This is really handy! Thanx.

[abdulkabirsultan]

Hi @danny-dainton
Thanks a lot for sharing this, that’s a really elegant approach!

I actually had a basic cleanup workaround for this earlier, mainly to clear transient variables after each run:

pm.test("Clean transient variables", function () {
    const keepVars = ["baseUrl", "authEmail", "authPassword"]; // vars I want to keep
    const allEnvVars = pm.environment.toObject();
    
    Object.keys(allEnvVars).forEach(varName => {
        // Delete vars that match common runtime patterns
        if (!keepVars.includes(varName) && /(id|token|order|session)/i.test(varName)) {
            pm.environment.unset(varName);
            console.log(`Removed ${varName}`);
        }
    });
});

It’s not as flexible as your packaged cleanup function, but it was handy for quickly removing transient variables like IDs or tokens after each run.

I really like your approach better though especially the scope parameter and the ability to exclude variables dynamically.

[danny-dainton]

Thank you for the suggestion during the challenge.

I did something about 6 years ago which looked very similar but this new script has a little bit more flexibility and configuration. It’s also not limited to only environments.

https://gist.github.com/DannyDainton/0a204d53e72464029a5aca8b2ae1592f

[abdulkabirsultan]

Wow, this is really impressive! I’m sure many people must have come up with creative workarounds for it. Hopefully, Postman adds this as a built-in feature soon.