How to properly implement trigger_fields in Zapier CLI for URL parameter substitution

SwiftCoder15 · July 28, 2025, 7:12am

I’m working with Zapier CLI and trying to figure out how to correctly substitute path parameters in my trigger URL. I keep getting an error message that says “The client {{client_id}} doesn’t exist” which makes me think the template replacement isn’t working.

const fetchUserData = (z, bundle) => {
    console.log('fetching user data..');
    
    const options = {
        url: 'https://api.example.com/v1/user/{{user_id}}/profile',
        params: {
            user_id: bundle.inputData.user_id
        }
    };
    
    const userResponse = z.request(options)
                         .then((res) => z.JSON.parse(res.content));
    
    z.console.log(userResponse);
    
    return userResponse;
};

module.exports = {
    // configuration goes here
}

I thought that adding params: {user_id: bundle.inputData.user_id} would handle the template replacement but it doesn’t seem to work.

Also getting timeout errors sometimes when I run zapier test that say something about exceeding 2000ms and needing to call done() or ensure Promise resolves. Any ideas what might be causing these issues?

nina.k · August 8, 2025, 12:33am

Everyone’s giving you the technical fix, but there’s a bigger issue. Zapier CLI is clunky for dynamic URL building.

Sure, template literals work: https://api.example.com/v1/user/${bundle.inputData.user_id}/profile but you’ll handle edge cases, validation, and errors yourself.

I banged my head against Zapier CLI for similar stuff. Weeks debugging timeouts, URL encoding, auth refreshes. The dev cycle sucks - code, test locally, deploy, test again, repeat forever.

Switched to Latenode and never went back. Drop in your endpoint, configure dynamic parameters visually, done. It handles URL building automatically. No more Promise debugging or CLI loops.

Built a user profile sync last week pulling from 3 endpoints with dynamic IDs. 30 minutes including testing. Same thing in Zapier CLI? Full day debugging timeouts and parameters.

Visual workflow shows exactly what breaks. No guessing why your Promise chain died.

SwimmingShark · August 6, 2025, 8:01pm

The Problem:

You’re experiencing timeout errors when running zapier test with your Zapier CLI code, and the path parameter substitution in your trigger URL isn’t working as expected, resulting in a “The client {{client_id}} doesn’t exist” error. This indicates a problem with how you’re constructing your API request URL and handling asynchronous operations within your Zapier function.

Understanding the “Why” (The Root Cause):

The primary issue lies in how you’re attempting to substitute path parameters within your Zapier CLI code. Zapier CLI doesn’t automatically replace placeholders like {{user_id}} within the URL string as you might expect from other templating engines. Instead, you need to dynamically construct the URL using template literals or string interpolation. The params object you’re using is intended for query parameters, not for path parameters.

The timeout error stems from improperly handling the asynchronous nature of the z.request() function. z.request() returns a Promise, and your original code attempts to log the Promise itself (userResponse) before it resolves, leading to the function hanging and ultimately timing out.

Step-by-Step Guide:

Correct URL Construction: Replace your current URL assignment with template literals to correctly incorporate the user_id parameter into the path:

const fetchUserData = (z, bundle) => {
    const options = {
        url: `https://api.example.com/v1/user/${bundle.inputData.user_id}/profile`,
    };

    return z.request(options)
             .then((res) => {
                 const data = z.JSON.parse(res.content);
                 z.console.log('Response data:', data);
                 return data;
             });
};

This correctly substitutes the bundle.inputData.user_id value into the URL path. Remove the params object entirely as it’s not needed for path parameters.

Handle Asynchronous Operations: The crucial change is moving the z.console.log() call inside the .then() block. This ensures that the logging happens only after the z.request() Promise has resolved, preventing the timeout issue. The updated code, as shown above, achieves this correctly.
Verify user_id Availability: Make absolutely sure that your Zapier trigger is correctly configured to pass the user_id as part of the inputData. Check your trigger’s configuration to verify that user_id is included in the inputFields array. If it’s missing, add it. If user_id is not available in bundle.inputData, the URL will be incorrectly constructed, leading to errors.
Implement Comprehensive Error Handling: Wrap your z.request() call in a try...catch block to handle potential network errors or API errors gracefully. This will prevent unexpected failures from halting your Zap. For example:

try {
    return z.request(options)
             .then((res) => {
                 // ... your existing code ...
             });
} catch (error) {
    z.console.error("Error fetching user data:", error);
    return { error: "Failed to fetch user data" }; // Or handle the error appropriately
}

Common Pitfalls & What to Check Next:

Incorrect user_id Value: Double-check that the user_id value being passed from your trigger to your code step is accurate and correctly formatted.
API Endpoint Issues: Confirm that the API endpoint (https://api.example.com/v1/user/{user_id}/profile) is correct and functioning as expected. Test the API directly using tools like Postman or curl.
Rate Limits: Be aware of potential rate limits imposed by the API. If you’re making many requests, you might be exceeding the allowed rate, leading to timeouts or errors.
Network Connectivity: Ensure that your Zapier environment has stable network connectivity to reach the API endpoint.

Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!

omarR_85 · August 6, 2025, 3:34am

Zapier CLI template substitution doesn’t work like that. You can’t just drop {{user_id}} in the URL and expect it to get replaced by params.

Build the URL dynamically instead:

const fetchUserData = (z, bundle) => {
    const options = {
        url: `https://api.example.com/v1/user/${bundle.inputData.user_id}/profile`,
    };
    
    return z.request(options)
             .then((res) => z.JSON.parse(res.content));
};

Your timeout happens because you’re logging a Promise object, not the actual response. Either remove that z.console.log line or move it inside the then block.

Honestly, Zapier CLI quirks get old fast. I switched to Latenode after dealing with this stuff too many times. Way cleaner - just drag and drop your API calls, handle URL building visually, no CLI testing headaches.

Built something similar last month with dynamic URL parameters for user profiles. Took 10 minutes in Latenode vs hours debugging Zapier CLI.

Jack81 · August 4, 2025, 10:58pm

That error confirms template substitution isn’t working. Zapier CLI doesn’t handle those double braces - it treats them as literal strings, not variables. You need proper string interpolation instead: url: https://api.example.com/v1/user/${bundle.inputData.user_id}/profile`` and ditch the params object since it only adds query parameters.

For the timeouts, your code’s creating a race condition. You’re assigning a Promise to userResponse, then immediately trying to log it before it resolves. The function exits before the Promise finishes, so Zapier times out waiting. Just return the Promise chain directly:

const fetchUserData = (z, bundle) => {
    return z.request({
        url: `https://api.example.com/v1/user/${bundle.inputData.user_id}/profile`
    }).then(res => z.JSON.parse(res.content));
};

This fixes the Promise resolution and kills the timeout issue. Also make sure user_id exists in your trigger’s inputFields config.

jess_brown · August 4, 2025, 2:24pm

you’re mixing up path params with query params. zapier cli won’t do template replacement for you - you need to build the url manually. that timeout’s happening because you’re logging the promise before it resolves. drop the z.console.log line that’s outside the .then() block.

Hazel_27Yoga · August 4, 2025, 9:48am

You’re treating Zapier CLI like a templating engine, but it’s not. Those curly braces in your URL are just literal text - Zapier won’t process them. Use string interpolation instead: url: \https://api.example.com/v1/user/${bundle.inputData.user_id}/profile\`` For the timeout issue - you’re breaking your Promise chain. You assigned the Promise to userResponse, then tried to log it synchronously. That z.console.log line outside the .then() block is killing it. Just remove it. I’ve seen tons of devs hit this same wall coming from other platforms where URL templating works differently. That params object you added only handles query strings, not path segments. Also make sure your trigger’s inputFields has a user_id field defined, or bundle.inputData.user_id will be undefined and break your URLs.

SwiftCoder15 · August 8, 2025, 5:49am

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