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 RepresentationUse 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.
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", }, "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", }, "$currency_symbol": "$", "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", }, "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", }, "Tag": [], "Location": "Business Address", "Reschedule_Note": null } ] }
|
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:
Recent Topics
Boost your Zoho Desk's performance by archiving tickets!
The longer your help desk operations are, the more likely it is to accumulate tickets that are no longer relevant. For example, ticket records from a year ago are typically less relevant than currently open tickets. Such old tickets may eventually lead
Opening balances - Accounts Receivable and Payable
Our accounting year starts on 1st August 2013 and I have a Trial Balance as at that date, including Accounts Receivableand Accounts Payable balances, broken down by each customer and supplier. Q1 - do I show my opening balance date as 31st July 2013 or
Announcing Kiosk 1.1 - Customize screen titles, configure new fields & actions, use values from your Kiosk to update fields, and more.
Hello all We are back again with more enhancements to Kiosk. So what's new? Enhancements made to the Components Add titles for your Kiosk screens and adjust its width to suit your viewing preferences. Three new fields can be added to your screen: Percentage,
Limited System because of Limited Number of Fields for Car Dealership
Dear Zoho Support, we want to have all the information about a car inside of a car record. We want to have Zoho CRM as our single source of truth for our data, but the limited number of fields are not allowing that. The data consist of: technical data
Cancel Subscription
Hi , Im want to cancel my account but without success please help me to do it
Making an email campaign into a Template
I used a Zoho Campaign Template to create an email. Now I want to use this email and make it a new template, but this seems to be not possible. Am I missing something?
Direct Access and Better Search for Zoho Quartz Recordings
Hi Zoho Team, We would like to request a few enhancements to improve how Zoho Quartz recordings are accessed and managed after being submitted to Zoho Support. Current Limitation: After submitting a Quartz recording, the related Zoho Support ticket displays
Multiple Cover Letters
We are using the staffing firm edition of Recruit and we have noticed that candidates cannot add more than one cover letter. This is a problem as they might be applying for multiple jobs on our career site and when we submit their application to a client,
URGENT: Deluge issue with Arabic text Inbox
Dear Deluge Support, We are facing an issue that started on 12/Feb/2026 with custom functions written using Deluge within Qntrl platform. Currently, custom functions do not accept Arabic content; it is replaced with (???) characters. Scenario 1: If we
File Conversion from PDF to JPG/PNG
Hi, I have a question did anyone every tried using custom function to convert a PDF file to JPG/PNG format? Any possibility by using the custom function to achieve this within zoho apps. I do know there are many third parties API provide this with
Prevent accidental duplicate entry of Customer Ordersome
Zoho Support has confirmed that Zoho currently does not have any method (using Deluge, flow or any other method) to alert a user when a sales order has been entered twice using the same customer reference number (i.e. a duplicate). Most ERP platforms
Now in Zoho One: Orchestrate customer journeys across apps with Zoho CommandCenter
Hello Zoho One Community! We’re excited to introduce Zoho CommandCenter as a new capability available in Zoho One. For the whole customer journey As Zoho One customers adopt more apps across sales, marketing, finance, and support, a common challenge emerges:
annualy customer report
we need a report per customer that looks like this invoic number cleaning laundry repair management 01 january xxx euro xx euro xx euro xxx euro 02 february xxx euro xxx euro x euro xxxx euro and so on the years 12 months is that possible to make and
Totals for Sales Tax Report
On the sales tax report, the column totals aren't shown for any column other than Total Tax. I can't think of a good reason that they shouldn't be included for the other columns, as well. It would help me with my returns, for sure. It seems ludicrous
Free Webinar: Zoho Sign for Zoho Projects: Automate tasks and approvals with e-signatures
Hi there! Handling multiple projects at once? Zoho Projects is your solution for automated and streamlined project management, and with the Zoho Sign extension, you can sign, send, and manage digital paperwork directly from your project workspace. Join
Exported Report File Name
Hi, We often export reports for information. It is time consuming to rename all the reports we export on a weekly basis, as when exported their default name is a seemingly random string of numbers. These numbers may be important, I'm not sure, but I am
Automatic Refresh on Page?
Hi everyone, We use a page as a dashboard which shows data for the laboratory and tasks pending etc. Is there a way to set the page to automatically refresh on a X time? Many thanks TOG
Hiding Pre-defined Views
You can enhance Zoho with custom views - but you cannot hide the pre-defined views. Most users focus on 4 or 5 views. Right now for EVERY user EVERY time they want to move to one of their 4 or 5 views - they have to scroll down past a long list of pre-defined views - we don't use ANY of the pre-defined views. Adding the feature to allow a predefined view to be hidden completely or only visible to certain users would be a big improvement in usability for Zoho CRM. This feature is already available
How do I edit the Calendar Invite notifications for Interviews in Recruit?
I'm setting up the Zoho Recruit Interview Calendar system but there's some notifications I don't have any control over. I've turned off all Workflows and Automations related to the Calendar Scheduling and it seems that it's the notification that is sent
Add RTL and Hebrew Support for Candidate Portal (and Other Zoho Recruit Portals)
Dear Zoho Recruit Team, I hope you're doing well. We would like to request the ability to set the Candidate Portal to be Right-to-Left (RTL) and in Hebrew, similar to the existing functionality for the Career Site. Currently, when we set the Career Site
App for Mac OS X please!
It would be awesome to have a mail app for Mac OS X that included all the cool features such as steams, calendar, tasks, contacts, etc. Most people prefer native apps, rather than running it through a web browser. I know that we can use the IMAP, CalDAV,
How to integrate Zoho CRM, Zoho Forms and a WIX Web Site
Attached video demonstrates how to use Zoho Forms included in Zoho One, to design a Contact Us form to be embedded into a WIX web site and integrated into Zoho CRM.
CRM x WorkDrive: File storage for new CRM signups is now powered by WorkDrive
Availability Editions: All DCs: All Release plan: Released for new signups in all DCs. It will be enabled for existing users in a phased manner in the upcoming months. Help documentation: Documents in Zoho CRM Manage folders in Documents tab Manage files
Introducing Workqueue: your all-in-one view to manage daily work
Hello all, We’re excited to introduce a major productivity boost to your CRM experience: Workqueue, a dynamic, all-in-one workspace that brings every important sales activity, approval, and follow-up right to your fingertips. What is Workqueue? Sales
Default Reminder Time in New Tasks or New Event?
Any way to change this from 1:00am? Thanks, Gary Moderation Update (February 2026): With the Calendar preferences, the default reminder time for Meetings, Appointments and All-Day Meetings can be set. Read more: Calendar preferences in Zoho CRM Regarding
Dynamic Field Folders in OneDrive
Hi, With the 2 options today we have either a Dynamic Parent Folder and lots of attachments all in that one folder with only the ability to set the file name (Which is also not incremented so if I upload 5 photos to one field they are all named the same
Right Shift key not sending to Zoho Assist environments
I'm unable to use Right Shift key in Zoho environments. Zoho environments are Win10. Computer I access from is Win 11. Issue started when I changed to Win 11. Have tried: - Multiple browsers - web client AND desktop client - 3rd party mapping tools to
Unable to Filter Retail Sales Orders & Need Paid/Unpaid Filter – Zoho Books
Hi Zoho Team, Recently you introduced Retail – Standard and Retail – Premium templates for Sales Orders. However, in the Sales Order module we still cannot filter or segregate Retail Sales Orders separately from normal B2B sales orders. Because of this,
About Meetings (Events module)
I was working on an automation to cancel appointments in zoho flow , and in our case, we're using the Meetings module (which is called Events in API terms). But while working with it, I'm wondering what information I can display in the image where the
PDF Annotation is here - Mark Up PDFs Your Way!
Reviewing PDFs just got a whole lot easier. You can now annotate PDFs directly in Zoho Notebook. Highlight important sections, add text, insert images, apply watermarks, and mark up documents in detail without leaving your notes. No app switching. No
Ability to assign Invoice Ownership through Deluge in FSM
Hi, As part of our process, when a service appointment is completed, we automated the creation of the invoice based on a specific business logic using Deluge. When we do that, the "Owner" of the invoice in Zoho FSM is defaulted to the SuperAdmin. This
How do you do ticket add ons in Backstage?
Hi Everyone, If you wanted to have general admin tickets and allow for add ons, like camping, or car or Carbon offset. What would you do? Peace Robin
From Zoho CRM to Paper : Design & Print Data Directly using Canvas Print View
Hello Everyone, We are excited to announce a new addition to your Canvas in Zoho CRM - Print View. Canvas print view helps you transform your custom CRM layouts into print-ready documents, so you can bring your digital data to the physical world with
validation rules doesn't work in Blueprint when it is validated using function?
I have tried to create a validation rule in the deal module. it works if I try to create a deal manually or if I try to update the empty field inside a deal. but when I try to update the field via the blueprint mandatory field, it seems the validation
Pull cells from one sheet onto another
Hello all! I have created an ingredients database where i have pricing and information and i want to pull from that database into a recipe calculator. I want it to pull based on what ingredient I choose. The ingredients database has an idea and i want
Emails Failing with “Relaying Issues – Mail Sending Blocked” in ZeptoMail
Hello ZeptoMail Support Team, We are facing an email delivery issue in our ZeptoMail account where emails are failing with the status “Process failed” and the reason “Relaying issues – Mail sending blocked.” Issue Details Agent Name: mail_agent_iwwa From
How does Zoho handle support operations for our EU users?
Dear Zoho users, We have some news and reminders about how we handle support operations for Zoho users in the EU Data Center. This is part of our broader commitment to ensuring GDPR compliance and providing secure data handling for all users. We'd like
Sender Email Configuration Error.
Hello Team, Hope you are all doing well. We are in the process of creating the Zoho FSM environment in the UAE. When we try to add the sender email address “techsupportuae@stryker.com”, we receive the error message: “Error occurred while sending mail
Layout Adjustment.
Hello Latha, Hope you are doing well. I wanted to check with you about adjusting the layout columns in the Service Report from the backend, as currently there is no capability for us to customize the layout from our end. Below is the output that I am
Anyone in Australia using Zoho Books AND has their account with NAB?
Hi I have an account with both NAB and Suncorp. Suncorp transaction come in the next day however NAB transactions take 4-5 business days to appear. eg: A deposit made today in my Suncorp will be imported into Zoho tomorrow. A deposit made today to the NAB account will be imported maybe Saturday (Friday overnight). I have contacted both Zoho and NAB but noone seems to know why. I was just wondering if anyone else in Australia uses NAB and has this issue (or doesn't) maybe we could compare notes and
Next Page