Manipulating Multi-Module Lookup Field using Zoho CRM APIs

Manipulating Multi-Module Lookup Field using Zoho CRM APIs

Hello everyone!

Welcome back to another week of Kaizen.
In this post, we explore the Multi-Module Lookup (MML) field in the Appointments module of Zoho CRM. You learn what an MML field is, how it works, and how to use it with Zoho CRM APIs.



Table of Contents:

  • What is a Multi-Module Lookup (MML) Field in Zoho CRM?
  • Use Cases for MML
  • How  the "Appointment For" (MML) field in the "Appointments" module works?
  • Creating a Record in the Appointments Module Using the Insert Records API
  • Retrieving a Record from the Appointments Module Using the Get Records API
  • Multi-module Lookup Using the COQL API
  • Multi-module Lookup Using the Bulk Read API
  • Frequently Asked Questions

What is a Multi-Module Lookup (MML) Field in Zoho CRM?

A Multi-Module Lookup (MML) field in Zoho CRM allows you to create a one-to-one relationship between a record in one module and a record from one of multiple other modules. Unlike a normal lookup field, which references a single module, an MML field can dynamically reference records from multiple modules. 
Without the MML field, users must create multiple lookup fields for each module, which complicates the CRM layout and user experience.

Note:
  • The multi-module lookup (multi_module_lookup) data type was introduced in Zoho CRM API version 3.
  • Currently, the MML field is available as a system-defined field named Appointment For in the Appointments module. 
  • The Appointment For field supports lookups to both Contacts and custom modules.
  • You cannot create a custom MML field in Zoho CRM.


Data Model Representation

MML's Data Model Representation

Use Cases for MML


Zylker Healthcare is a multi-specialty hospital that uses Zoho CRM to maintain its appointment scheduling process. 

In this setup, Zylker maintains two key modules:
  • Contacts module - Stores records of physicians and surgeons, including attending physicians, specialists, and surgeons who diagnose and refer patients.
  • Patients module - A custom module used to maintain records of all patients.

To improve the appointment booking process, Zylker uses the "Appointment For" Multi-Module Lookup (MML) field in the Appointments module. This field lets Zylker manage an appointment with either a Physician/Surgeon or a Patient, eliminating the need for multiple lookup fields.

How  the "Appointment For" (MML) field in the "Appointments" module works?

  • When creating an appointment, the user selects the "Appointment For" field.
  • The field displays records based on the selected module, either the Contacts or  Patients. 
  • The user selects the appropriate record (Contact or Patients) for the appointment.
  • A related list is automatically created in the selected module (Contact or Patients) as the Open Activities / Closed Activities to display all appointments associated with that record.

Creating a Record in the Appointments module using the Insert Records API

Before creating a record in the Appointments module via the Insert Records API, make sure you know the API names of the system-defined mandatory fields. These fields are required to create an appointment successfully.

System-defined Mandatory Fields:
  • Appointment_For (MML field)
  • Service_Name
  • Appointment_Start_Time
  • Appointment_Name
  • Member
  • Location

The below image shows how these system-defined mandatory fields appear in the Appointments module UI:

System-defined mandatory keys in the Appointments Module in UI view.

API calls you have to make before creating a record:

Before inserting a record into the Appointments module, it is important to know the API names of the fields and their parent modules. 

i. Use the GET - Module Metadata API to know the API name of the module. In our case, the Appointments module.

Request URL : {api-domain}/crm/v8/settings/modules
Request Method : GET

Sample Response :

 
In the API response, search for the module with "module_name": "Appointments" and check the value of the "api_name" key to get the API name of the module. This is the name you will use in all related API calls.

ii. Use the GET - Fields Metadata API and get fields metadata for the Appointments module. Here, you can find the API names of the mandatory fields along with other fields present in the Appointments module. 

Below is the API call & response for the multi-module lookup field along with other mandatory fields.

Request URL : {api-domain}/crm/v8/settings/fields?module=Appointments__s
Request Method : GET

Sample Response :


Note: The above image highlights only the key properties of the Multi-Module Lookup (MML) field from the field metadata response. The complete API response contains additional properties not shown here.

In the response:
  • The multi-module lookup field is identified by the key "data_type" with the value "multi_module_lookup".
  • The associated modules supported by the MML field (e.g., Contacts, Patients) are listed under the "modules" key.
  • Other mandatory fields like Service Name, Appointment Name, and Appointment Start Time can be identified by "system_mandatory": true.
The keys of the above multi_module_lookup JSON object are explained below:


"multi_module_lookup": {
    "display_label": "Appointments", // Display label of the module where the MML field is used
    "api_name": "Appointments__s", // API name of the Appointments module
    "modules": [ //List of modules associated with the Appointments module. 
        {
            "api_name": "Contacts", //API name of the associated module 
            "module_name": "Contacts", // Display Name of the module 
            "id": "5725767000000002179" //Unique ID of the module
        },
        {
            "api_name": "Patients", //API name of the associated custom module
            "module_name": "Patients", //Display label of the module
            "id": "5725767000006473007" //Unique module ID
        }
    }
]
},

Note: 
  • You cannot add or remove modules from the Multi-Module Lookup (MML) field using APIs. These actions are only available through the Zoho CRM UI.
  • Once a module is disassociated from the MML field, existing records associated with that module will remain in the Appointments module, and you will no longer be able to associate newly created records from the disassociated module using the MML field. 
The remaining system-defined mandatory fields, along with their API names, are listed below.

 

 System-defined Mandatory Field Names

 

 

System-defined Mandatory Field API Names

Service Name

Service_Name

Appointment Start Time

Appointment_Start_Time

Appointment Name

Appointment_Name

Member

Owner

Location

Location


Note: The system-defined mandatory fields can be identified by "system_mandatory": true.

Search the system-defined mandatory field names and get their API names.
With the field API names, use the following request and sample input body to create a record in the Appointments module using the Insert Records API.

Request URL : {{api-domain}}/crm/v8/Appointments__s
Request Method : POST

Request Body :

{
    "data": [
        {
            "Appointment_Name": "General Consultation",
            "Owner": {
                "name": "Patricia Boyle",
                "id": "5725767000000411001",
                "email": "patricia@zohotest.com"
            },
            "Appointment_Start_Time": "2025-04-15T13:00:00-07:00",
            "Appointment_End_Time": "2025-04-15T13:30:00-07:00",
            "Appointment_For": {
                "module": {
                    "api_name": "Contacts",
                    "id": "5725767000000002179"
                },
                "name": "John Doe",
                "id": "5725767000005607020"
            },
            "Service_Name": {
                "name": "General Check-up",
                "id": "5725767000006387029"
            },
            "Location": "Business Address"
        }
    ]
}


Sample Response:


{
    "data": [
        {
            "code": "SUCCESS",
            "details": {
                "Modified_Time": "2025-05-06T20:33:42-07:00",
                "Modified_By": {
                    "name": "Patricia Boyle",
                    "id": "5725767000000411001"
                },
                "Created_Time": "2025-05-06T20:33:42-07:00",
                "id": "5725767000006390001", //Unique ID if the newly created record. Please note that this record ID will be used in the following API get and update operations.
                "Created_By": {
                    "name": "Patricia Boyle",
                    "id": "5725767000000411001"
                }
            },
            "message": "record added",
            "status": "success"
        }
    ]
}



Note:
Only Contacts and custom modules are supported in the Multi-Module Lookup field. If you try to associate a new record with a module that has been removed from the MML field or an unsupported module in the MML field, the following error will be thrown. 


Retrieving a Record from the Appointments Module Using the Get Records API

Request URL : {{api-domain}}/crm/v8/Appointments__s/5725767000006390001
Request Method: GET

Request Response:

{
    "data": [
        {
            "Owner": {
                "name": "Patricia Boyle",
                "id": "5725767000000411001",
                "email": "patricia@zoho.com"
            },
            "$currency_symbol": "$",
            "Address": null,
            "Appointment_Start_Time": "2025-04-15T13:00:00-07:00",
            "Cancellation_Reason": null,
            "$field_states": null,
            "Appointment_For": {
                "module": {
                    "api_name": "Contacts",
                    "id": "5725767000000002179"
                },
                "name": "John Doe",
                "id": "5725767000005607020"
            },
            "Rescheduled_To": null,
            "$sharing_permission": "full_access",
            "Reschedule_Reason": null,
            "Additional_Information": null,
            "Last_Activity_Time": null,
            "Cancelled_Time": null,
            "Cancellation_Note": null,
            "Modified_By": {
                "name": "Patricia Boyle",
                "id": "5725767000000411001",
                "email": "patricia@zoho.com"
            },
            "Reschedule_Count": 0,
            "Rescheduled_By": null,
            "id": "5725767000006390001",
            "Rescheduled_Time": null,
            "Remind_At": null,
            "Appointment_End_Time": "2025-04-15T13:30:00-07:00",
            "Status": "Overdue",
            "Modified_Time": "2025-05-06T20:04:38-07:00",
            "Service_Name": {
                "name": "General Check-up",
                "id": "5725767000006387029"
            },
            "Created_Time": "2025-05-06T20:04:38-07:00",
            "testing": null,
            "Rescheduled_From": null,
            "Cancelled_By": null,
            "$editable": true,
            "Appointment_Name": "General Consultation",
            "Duration": 30,
            "Record_Status__s": "Available",
            "Created_By": {
                "name": "Patricia Boyle",
                "id": "5725767000000411001",
                "email": "patricia@zoho.com"
            },
            "Tag": [],
            "Location": "Business Address",
            "Reschedule_Note": null
        }
    ]
}


Updating MML Field Value Using the Update Records API

Request URL : {{api-domain}}/crm/v8/Appointments__s/5725767000006390001
Request Method: PUT

Request Body:

{
    "data": [
        {
            "Appointment_Start_Time": "2025-04-16T14:00:00-07:00", //Updating the Appointment_Start_Time
            "Appointment_End_Time": "2025-04-16T14:30:00-07:00", //Updating the Appointment_End_Time
            "Appointment_For": {
                "module": {
                    "api_name": "Employees", //Updating a different module
                    "id": "5725767000002161028"
                },
                "name": "Patrica", //A record from the Employees module
                "id": "5725767000006272001" //unique ID of the record
            }
        }
    ]
}


Multi-module Lookup Using the COQL API

Querying Inner Fields of Linked Modules within the MML Field

With the COQL API, you can query inner fields of linked modules within a Multi-Module Lookup (MML) field. This provides deeper insights into related fields data in a module. This query support is available from Zoho CRM API Version 7.

Sample Query:


{
 "select_query": "select 'Appointment_For->Contacts.Lead_Source' from Appointments__s where id is not null"
}

The above query retrieves the Lead Source field from the Contacts module within the Appointment_For MML field. 


Sample Response:



Querying Multi-Module Lookup Module Name

Querying the module name associated with each record in a Multi-Module Lookup (MML) field. This query support is available from Zoho CRM API Version 7.

Sample Query:

{
"select_query": "select Appointment_For.module.api_name, Appointment_For from Appointments__s where id is not null"
}


The Appointment_For.module.api_name returns the module name (e.g., Contacts or Accounts) for each record linked in the Appointment_For MML field.

Sample Response:


Multi-module Lookup Using the Bulk Read API

Bulk Read API allows you to fetch a large set of data i.e., you can fetch a maximum of 2,00,000 records in a single API call. 
Specify the API name of the Appointments module in the module JSON object when making API calls. Refer to the following section for an example.

Request Method : POST

Request Body :

{
    "callback": {
        "method": "post"
    },
    "query": {
        "module": {
            "api_name": "Appointments__s" //API name of the Appointments module
        },
        "file_type": "csv"
    }
}


Note: The Appointment_For field cannot be used in the criteria.

As the API is an asynchronous API, the response will not be available instantly; the bulk read job is scheduled, and the status can be checked. Once the job is completed, you will be notified in the callback URL. The records are available in a downloadable CSV file or ICS file (for events). See the Bulk Read API document to know how to view the status of the scheduled job and download the file, along with more sample requests and responses.

Sample Exported Response 



Frequently Asked Questions

1. Which modules are currently supported in the MML field?

Only Contacts and custom modules can be associated with an MML field.

2. What error is thrown if I try to associate a record with a removed or unsupported module in the MML field?

If you try to associate a record with a removed or unsupported module in an MML field, the system will throw an "INVALID_DATA" error.

3. Is the MML field available for all modules?

No, as of Zoho CRM API Version 8, the MML field is available only as a system-defined field in the Appointments module.

4. How do I get the list of modules associated with an MML field?

You can use the GET - Fields Metadata API for the Appointments module and look for the field with "data_type" : "multi_module_lookup" and check its "modules" JSON array.

5. Can I add or remove modules from a Multi-Module Lookup (MML) field via API?

Adding or removing modules in an MML field is not supported via API. These actions can only be done through the Zoho CRM UI.

6. What happens if I remove a module from an MML field?

If a module is removed from the MML through Zoho CRM UI, it can no longer be associated with new records, but existing records linked to that module will remain unaffected.

7. Is MML field supported in the Bulk Write API?

As of Zoho CRM API Version 8, the MML field is available only in the Appointments module as a system-defined field. The Appointments module is not supported in the Bulk Write API.

8. Is MML field supported in the Search API?

The MML field is not currently supported in the Search API.



We trust that this post meets your needs and is helpful. Let us know your thoughts in the comment section or reach out to us at support@zohocrm.com

Stay tuned for more insights in our upcoming Kaizen posts!

Cheers!!!


Related Readings:


    • Sticky Posts

    • Kaizen #197: Frequently Asked Questions on GraphQL APIs

      🎊 Nearing 200th Kaizen Post – We want to hear from you! Do you have any questions, suggestions, or topics you would like us to cover in future posts? Your insights and suggestions help us shape future content and make this series better for everyone.

    • Kaizen #198: Using Client Script for Custom Validation in Blueprint

      Nearing 200th Kaizen Post – 1 More to the Big Two-Oh-Oh! Do you have any questions, suggestions, or topics you would like us to cover in future posts? Your insights and suggestions help us shape future content and make this series better for everyone.

    • Celebrating 200 posts of Kaizen! Share your ideas for the milestone post

      Hello Developers, We launched the Kaizen series in 2019 to share helpful content to support your Zoho CRM development journey. Staying true to its spirit—Kaizen Series: Continuous Improvement for Developer Experience—we've shared everything from FAQs

    • Kaizen #193: Creating different fields in Zoho CRM through API

      🎊 Nearing 200th Kaizen Post – We want to hear from you! Do you have any questions, suggestions, or topics you would like us to cover in future posts? Your insights and suggestions help us shape future content and make this series better for everyone.

    • Client Script | Update - Introducing Commands in Client Script!

      Have you ever wished you could trigger Client Script from contexts other than just the supported pages and events? Have you ever wanted to leverage the advantage of Client Script at your finger tip? Discover the power of Client Script - Commands! Commands

    • Recent Topics

    • Possible to bold or indent text in the description field?

      As part of one item, I often have a detailed description that would be much easier to read if there was the ability to have a bulleted list or bold text and the like. Is this possible? My last invoicing software allowed markup in the field so, for example, an asterisk meant a bullet. I haven't been able to find any documentation related to this.  Any information would be appreciated. Thank you.

    • How can I setup Zoho MCP with Chat GPT

      I can set up custom connections with Chat GPT but I cat an error when I try to set it up. The error is: "This MCP server can't be used by ChatGPT to search information because it doesn't implement our specification: search action not found" Thoughts?

    • Formatting of Balance Sheet and Profit & Loss Reports

      The default format of the Balance Sheet and P&L Reports are based on the Account Types and then the individual accounts within the Chart of Accounts. These are then ordered alphabetically under these sub-headings and one is unable to re-order these or

    • UK MTD reports concerning turnover and cerash accounting

      Hi I am a sole trader, and I have just started with Zoho Books in order to comply with the new HMRC requirements. I use 'cash basis' - which I understand to mean that income is when the cash comes in (not the invoice date) and expenses are when they are

    • Retainer Invoice.

      Why ZOHO not have facilities to deduct partially advance payment from an invoice.

    • Collaborate Feature doesn't work

      Hello Team. It seems that the collaborate section is broken? I can post something but it all appears in "Discussions". In there is no way how I would mark something as Draft, Approval, post or any of the other filter categories? Also if I draft a post

    • IMAP Server not responding.

      Trying to connect a phone via IMAP and getting "imap.zoho.com not responding." Is the server down, for maintenance or otherwise? I've tried this on two different devices and got the same error on both.

    • Vendor Signatures Needed for Purchase Orders

      Hello everyone, We have a unique requirement that necessitates that Vendors & Suppliers formally acknowledge our Purchase Orders upon receipt. I was hoping that there would be an option to do so in Zoho Books, but that does not appear to be the case.

    • Share saved filters between others

      Hi, I am in charge to setup all zoho system in our company. I am preparing saved filters for everybody, but the only one can see its me. How can others see it? Thanks

    • GST Slabs Redefined: Stay Compliant Using Zoho Books!

      Hello Everyone! The Government of India is rolling out new GST rates, a major reform aimed at simplifying the current tax structure starting 22 September 2025. GST will move from four slabs (5%, 12%, 18%, 28%) to two main slabs (5% and 18%), plus a special

    • Kanban view on Zoho CRM mobile app!

      What is Kanban? The name doesn't sound English, right? Yes, Kanban is a Japanese word which means 'Card you can see'. As per the meaning, Kanban in CRM is a type of list view in which the records will be displayed in cards and categorized under the given

    • Presenting ABM for Zoho CRM: Expand and retain your customers with precision

      Picture this scenario: You're a growing SaaS company ready to launch a powerful business suite, and are looking to gain traction and momentum. But as a business with a tight budget, you know acquiring new customers is slow, expensive, and often delivers

    • No practical examples of how survey data is analyzed

      There are no examples of analysis with analytics of zoho survey data. Only survey meta data is analyzed, such as number of completes, not actual analysis of responses, such as the % in each gender, cross-tabulations of survey responses. One strange characteristic of Zoho analytics is that does not seem aware of how Zoho Survey codes 'multiple response' questions. These are questions where more than one option can be selected from a list. Zoho Survey stores this data as text, separated by commas within

    • Zoho Creator as LMS and Membership Solution

      My client is interested in using Zoho One apps to deploy their membership academy offer. Zoho Creator was an option that came up in my research: Here are the components of the program/offer: 1. Membership portal - individual login credentials for each

    • Adding Chargebee as a Data Connector

      Is it possible to get Chargebee added as a Zoho Analytics data connector?

    • Zoho CRM - Custom Views for Portal Users

      I'm looking for an option to customise custom views for portal users in CRM. It would be great if "portal user" was a permission on custom views.

    • Webform & spam

      Hi, We set up 2 webform on our website, fowarding the content to Zoho CRM. Since it has been opened up, we are getting lot of spam message (for now about 20 a day). To lower the  amount of false new leads we added the captcha field and new enquieries are send to the Approval Leads list. However we still get some spam. Is there any "anti spam" mechanism built in Zoho CRM, or how is the best way to avoid these kind of spam ? Thanks

    • Elevate your CX delivery using CommandCenter 2.0: Simplified builder; seamless orchestration

      Most businesses want to create memorable customer experiences—but they often find it hard to keep them smooth, especially as they grow. To achieve a state of flow across their processes, teams often stitch together a series of automations using Workflow

    • Dropbox to Workdrive

      Namaste, Trust you all are doing well. Wanted to check how this can be done with Zoho flow. I typically receive dropbox links from my clients. Is there a way where I can provide the link to Zoho flow and it downloads the files from dropbox link to a work

    • Deals by Stages Funnel not showing in correct order

      Using the Stage-Probability Mapping for the Deals module we have created a steps our deals will pass through, RFQ, Closed/Lost, Declined/No-Go, Pricing, Submitted, Negotiations, Won. However when I view the Deal By Stages Funnel it does not show in the

    • Adding a developer for editing the client application with a single user license

      Hi, I want to know that I as a developer I developed one application and handed over to the customer who is using the application on a single user license. Now after6 months customer came back to me and needs some changes in the application. Can a customer

    • Turning off the new UI

      Tried the new 'enhanced' UI and actively dislike it. Anyone know how to revert back?

    • Message "...does not support more than 100 distinct values..." WHY????

      I get this message on one of my reports: Sorry, Zoho Reports currently does not support more than 100 distinct values in columns. 'Account Name * Sum(Amount),Count(Amount Tier)' contains more than 100 distinct values.  Possibly, you can apply filter to reduce the number of distinct values in 'Account Name' or drop the 'Account Name' field in Rows. I want to list all ACCOUNT NAMES (about 500) with SALES BY ACCOUNT.  What is blocking this?

    • Attention API Users: Upcoming Support for Renaming System Fields

      Hello all! We are excited to announce an upcoming enhancement in Zoho CRM: support for renaming system-defined fields! Current Behavior Currently, system-defined fields returned by the GET - Fields Metadata API have display_label and field_label properties

    • Confirmation prompt before a custom button action is triggered

      Have you ever created a custom button and just hoped that you/your users are prompted first to confirm the action? Well, Zoho knows this concept. For example, in blueprint, whenever we want to advance to the next state by clicking the transition, it is

    • Cost of good field

      Is there a way we can have cost of good sold as a field added to the back end of the invoicing procedure and available in reports?

    • How to create auto populate field based on custom module in Zoho CRM?

      Hello, i'm still new to Zoho CRM and work as administrator in my company. Currently, I'm configuring layout for Quotes Module. So, the idea is, I've created a read-only field in Quotes called "Spec". I want this field automatically filled with Specification

    • Rich Text For Notes in Zoho CRM

      Hello everyone, As you know, notes are essential for recording information and ensuring smooth communication across your records. With our latest update, you can now use Rich Text formatting to organize and structure your notes more efficiently. By using

    • Date triggering Workflow rule

      I have a function triggered by a workflow rule. The function takes a date and creates a task for that date and fills in a field with the name of the day for that date. It also updates the status field of the record. The workflow rule is set to run whenever

    • Change Last Name to not required in Leads

      I would like to upload 500 target companies as leads but I don't yet have contact people for them. Can you enable the option for me to turn this requirement off to need a Second Name? Moderation update (10-Jun-23): As we explore potential solutions for

    • Office 365 and CRM mail integration: permission required

      Has anyone run into this weird problem? My email server is Office 365. When I try to configure Zoho CRM to use this server, a Microsoft popup window opens requesting user and password. After entering that, I get a message in the Microsoft window saying

    • Tables improvement ideas / features

      Heya, I've been using Zoho Tables for a few months now and wanted to post some features that I think will be greatly beneficial for the tool: 1. Ability to delete a record in automation or move a record in automation. - Usecase: I move a record from one

    • Deluge - Can't get phone number SalesIQ

      Hey folks, I’m building a custom plug for SalesIQ that’s supposed to register leads into Zoho CRM. The SalesIQ chat is being implemented on WhatsApp, and in my plug I’m using this line: mobile_clean = session.get("phone").get("value"); From what I understand,

    • Zoho CRM button to download images from image upload field

      Hello, I am trying to create a button in Zoho CRM that I can place in my record details view for each record and use it to download all images in the image upload fields. I tried deluge, client scripts and even with a widget, but feel lost, could not

    • how to differentiate if whatsapp comes from certain landing page?

      I create a Zobot in SalesIQ to create a Whatsapp bot to capture the lead. I have 2 landing pages, one is SEO optimized and the other want is optimized for leads comes from Google Ads. I want to know from which landing page this lead came through WhatsApp

    • Zoho Desk - Community

      As a regular user of Zoho Cares Community I would really love to see the publish date of articles. For example, when I look at Announcements, it would be very beneficial to see which ones were posted recently, over those which have just and a recent comment.

    • access to quartz for my customers

      Hi how can I have access to the application quartz you use for us to send you screen rocording, this feature would be immensely useful for our customers support https://quartz.zoho.com/

    • Issue with Inline Images in Email Reply via Zoho Desk API

      Hi, I am attempting to send inline images in an email reply using the Zoho Desk API, but the images are not being displayed inline for the recipient. I have followed this documentation: https://desk.zoho.com/DeskAPIDocument#Uploads https://desk.zoho.com/DeskAPIDocument#Threads#Threads_SendEmailReply

    • How to search a value stored in a subform?

      Hello, We store serial numbers in subforms but now we would like to be able to search the values to be able to easily find the record with the serial number. I saw that it's not possible to search such values through global search but is it possible to do it an other way? Thank you,

    • Field Dependency Not Working on Detail Page in Zoho Desk

      Hi Support Team, I’ve created field dependencies between two fields in Zoho Desk, and they are working correctly on the Create and Edit layouts. However, on the Detail page, the fields are not displaying according to the dependencies I’ve set — they appear

    • Next Page