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How to Test a Zoho CRM Standalone Function REST API Using Postman (Step-by-Step Guide)

How to Test a Zoho CRM Standalone Function REST API Using Postman (Step-by-Step Guide)


In this tutorial, you will learn how to create a Standalone Function in Zoho CRM, write a simple Deluge script to create a contact record, generate a REST API endpoint from that function, and verify that it works correctly using Postman — all with step-by-step instructions and copy-paste code examples.

What is Zoho CRM?

Zoho CRM is a cloud-based Customer Relationship Management platform that helps businesses organize customer data, track sales leads, manage deals, and automate repetitive workflows — all from a single, intuitive interface. It is used by over 250,000 businesses worldwide, from small startups to large enterprises.

 Think of Zoho CRM as a smart digital notebook for your business. Instead of scribbling customer names and follow-up reminders on paper, Zoho CRM stores everything securely in the cloud — searchable, shareable, and always up to date.

Beyond data storage, Zoho CRM supports powerful developer capabilities through Deluge — Zoho's own scripting language — which lets you write custom business logic, call external APIs, and automate complex workflows directly inside your CRM.

What is Postman?

Postman is one of the most popular API development and testing tools available today. It allows developers to send HTTP requests to any API endpoint and inspect the response — without writing a single line of client-side code. It is widely used to verify that an API is working correctly before integrating it into a live application.

 If your Zoho CRM function is the kitchen and the API is the menu, Postman is the waiter — you tell it what you want, it places the order, and brings back exactly what was prepared so you can check if it is correct.

Postman supports all major HTTP methods (GET, POST, PUT, DELETE), request headers, authentication, and JSON body formatting — making it the ideal tool for testing Zoho CRM REST API endpoints.

What is a Zoho CRM Standalone Function?

A Standalone Function in Zoho CRM is a custom Deluge script that runs independently — not tied to any specific module trigger, button, or workflow rule. Unlike other function types, a Standalone Function can be exposed as a publicly accessible REST API endpoint by Zoho CRM, which you can then call from Postman, your website, a mobile app, or any third-party service.

This makes Standalone Functions extremely powerful for building custom integrations without needing a separate backend server.

Prerequisites

Before you begin, make sure you have the following ready:

  • An active Zoho CRM account (any paid plan supports Functions)
  • Postman installed — download it free here
  • Basic understanding of what an API is (helpful but not required)
  • Developer access within your Zoho CRM organization

Step-by-Step Tutorial

Let's walk through the complete process: creating the function, writing the Deluge code, generating the REST API URL, and testing it live in Postman.

1
Create a Standalone Function in Zoho CRM
  1. Log in to your Zoho CRM account.
  2. Click the Settings icon (gear) in the top-right corner.
  3. Scroll to the Developer Hub section and click Functions.
  4. Click + New Function and fill in:
    • Function Name: CreateContact
    • Display Name: e.g., Create Contact via API
    • Description: e.g., Creates a new contact record via REST API
  5. Under Category, select Standalone.
  6. Click Create to open the function editor.
ℹ️ Selecting Standalone as the category is critical. Only Standalone Functions can be exposed as REST API endpoints in Zoho CRM. Other categories (Button, Workflow) are tied to internal triggers and cannot be called externally.
2
Write the Deluge Function Code

In the function editor, paste the following Deluge code. This script builds a contact data map and uses Zoho's built-in zoho.crm.createRecord task to create a new contact in CRM.

 Deluge · CreateContact function
// Step 1: Build a map with the contact's details
mape = Map();
mape.put("First_Name", "Test record-4");
mape.put("Last_Name",  "Gupta");
mape.put("Email",      "gj@yopmail.com");
mape.put("Phone",      "7078345678");

// Step 2: Create the record in the Contacts module
resp = zoho.crm.createRecord("Contacts", mape);

// Step 3: Log and return the response
return resp;

This code creates a new contact named "Test record-4 Gupta" in your CRM Contacts module. After pasting the code, click Save.

✓ Use the Execute button in the Zoho function editor to run the code directly before generating the REST API. This verifies the logic is working before exposing it externally.
3
Generate the REST API URL
  1. Go back to the Functions list in Zoho CRM Settings.
  2. Find the function you just created (CreateContact).
  3. Click the three-dot menu (⋯) icon next to the function name.
  4. Select REST API from the dropdown.
  5. Toggle on the API Key option to enable key-based authentication.
  6. Copy the generated URL — you will need it in the next step.
  7. Click Save.
⚠️ Keep your API key confidential. Anyone with this key can call your function and create records in your Zoho CRM account. Never share it publicly or commit it to a code repository.
4
Test the API in Postman
  1. Open Postman on your computer.
  2. Click New → HTTP Request.
  3. Paste the copied URL from Step 3 into the URL field.
  4. Set the HTTP method to POST.
  5. Click the Body tab → select raw → choose JSON from the format dropdown.
  6. Paste the following JSON in the body editor:
{} Request body · JSON
{
  "First_Name": "Test record-4",
  "Last_Name":  "Gupta",
  "Email":      "gj@yopmail.com",
  "Phone":      "7078345678"
}

Click Send. If everything is configured correctly, Postman will return a success response confirming the new contact was created in Zoho CRM.

ℹ️ After a successful test, log in to Zoho CRM and navigate to the Contacts module. You should see the new contact “Test record-4 Gupta” listed there, confirming the full API flow is working end-to-end.

Watch the Full Video Tutorial

Prefer to follow along visually? Watch the complete step-by-step walkthrough below. The video covers everything in this post — from creating the Standalone Function in Zoho CRM to testing the REST API live in Postman.

▶️ If you find the video helpful, consider liking and subscribing for more Zoho CRM developer tutorials — new videos are posted regularly!

Helpful Resources

Use these official references to explore Zoho CRM development and Postman further:

Conclusion

You have now completed the full workflow: creating a Standalone Function in Zoho CRM, writing a Deluge script to create a contact record, generating a REST API endpoint from that function, and successfully testing it using Postman.

This pattern is extremely powerful for building custom integrations. Once you understand how Standalone Functions work as REST APIs, you can expose any business logic in Zoho CRM to external systems — whether that is a website form, a mobile app, or a third-party automation platform like Zapier or Make.

The same approach works for updating records, querying data, or triggering custom workflows — simply change the Deluge logic inside the function.

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