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
Condition based aggregate fields in subforms
Hello everyone, We're excited to inform you about the latest enhancements made to our aggregate field capabilities in subforms; create aggregate fields based on conditions! An aggregate field is a column on which a mathematical function has been applied.
SalesIQ Tip for Admins: Your Safety Net for Data Recovery
Ever clicked 'Delete' in your SalesIQ and then realized it was the wrong item? Maybe it was a prospect's chat that held important context you needed to refer to later on. Or, maybe you deleted an elaborate Zobot that you were still testing or planning
Depreciated mergeAndStore Function Help!
Hello, I have a function designed to create a PDF containing information from the fields in a Deals record. There is a Writer Mail Merge template in WorkDrive that is populated via Deluge code, and a copy of the resulting PDF is then attached to the record.
Can I execute two 'functions' when completing a mail merge from CRM?
Hi, I have set up a mail merge from CRM Deals to a template. I want a copy of this to be saved in Workdrive, and then a copy also saved back into the deal record from which the merge occurred. I can do both independent of each other, and managed to get
External Share > Edit: Cannot Create Zoho Files
Hi Zoho, When we create an external share link with Edit permission, our external users are unable to create a Zoho file (Zoho Writer, Zoho Sheet and Zoho Show). They can only upload files. They can edit the Zoho files if we create them internally and
Using IMAP configuration for shared email inboxes
Our customer service team utilizes shared email boxes to allow multiple people to view and handle incoming customer requests. For example, the customer sends an email to info@xxxx.com and multiple people can view it and handle the request. How can I configure
the custom domain forwards by default to the old career site / how to switch it off??
dear friends, how to switch off the old version of the career site?? The set up custom domain forwards directly to the old site, so that I cant publish it... Any ideas? Thank you! KR, Victoria
Zoho learn Custom portal - networkurl & CustomPortalId
I want to get my individual account’s networkurl and customportalId to use in this API: https://learn.zoho.com/learn/api/v1/portal/<networkurl>/customportal/<customportalId>/manual
How can I retrieve the networkurl and customportalId using the API? I
Zoho Mail iOS app update - RTL languages support and access emails using permalink and universal link, image upload resolution
Hello everyone! In the most recent version of the Zoho Mail iOS app update, we have brought in support for RTL languages(Arabic and Urudu), providing a seamless reading experience with proper text alignment and layout throughout the app. We have also
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
Why are emails sending with @viazohocrm.com ?
I just sent out mass emails from CRM. They are sending from the email below and people cannot reply, and they are getting this message: Address not found Your message wasn't delivered to sales.XXXXXXXX.com.au@viazohocrm.com because the address couldn't
Duplicating and referencing datasets
I am moving from PowerBI to Zoho Analytics and while I find Zoho easier to use in many ways, there is one function that I use in PowerBI that I have not been able to find in Zoho. I have several data sets that I need to modify in different ways to get
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
Zoho Inventory Now Supports VeriFactu for Businesses in Spain
Starting from January 1, 2026, Spain requires real-time invoice reporting for all B2B transactions. From July 2026, this requirement will extend to B2C transactions as well. All reporting must be carried out through the VeriFactu to AEAT (Agencia Estatal
Conditional Email Forwarding
How can I set conditional email forwarding of the users? For example: Mail should be forwarded to a address only if it comes from a particular sender. So, I want such email forwarding, which forwards mails based on particular conditions, like the incoming
Why am I seeing deleted records in Zoho Analytics syncing with Zoho CRM?
I have done a data sync between Zoho CRM and Zoho Analytics, and the recycle bin is empty. Why do I see deleted leads/deals/contacts in Zoho Analytics if it doesn't exist in Zoho CRM? How can I solve this problem? Thanks
Enhancements to Zoho Map integration tasks
Hello everyone, We're excited to announce enhancements to the Zoho Map integration tasks in Deluge, which will boost its performance. This post will walk you through the upcoming changes, explain why we're making them, and detail the steps you need to
Let’s Talk Recruit: Meet Zia, your all-in-one AI assistant (Part-3)
Welcome back to the Let’s Talk Recruit series. In the part 2 post, we explored how Zia has evolved with smarter summaries and seamless AI-assisted content creation. This time, we’re diving into the latest upgrades that take productivity even further —
Announcing Early Access to "Zoho CRM for Everyone" — A new and exciting update to Zoho CRM
Update : Zoho CRM For Everyone's Nextgen Interface gets an upgrade! Hello everyone, We’ve updated the Zoho CRM for Everyone Nextgen interface based on your feedback. The UI is now simpler with a unified sidebar, a more visible global search and features
Problem with signature on zoho survey
Hello, I'm trying to export individual responses with signatures on zoho survey. But the signatures on some of my surveys are not exported as the original image, but as a generic image, same for all (screen joins). Is there a solution to have the signatures
Unable to verify domain for Zoho People
I have added TXT records in my DNS (GoDaddy) [screenshot attached], but unable to verify even after 12 hours after adding. On checking the console, it shows some errors [screenshot attached]. It appears that the verification flow is broken - please provide
Zoho Invoice Now Supports VeriFactu for Businesses in Spain
Starting from January 1, 2026, Spain requires real-time invoice reporting for all B2B transactions. From July 2026, this requirement will extend to B2C transactions as well. All reporting must be carried out through the VeriFactu to AEAT (Agencia Estatal
Zoho Billing Now Supports VeriFactu for Businesses in Spain
Starting from January 1, 2026, Spain requires real-time invoice reporting for all B2B transactions. From July 2026, this requirement will extend to B2C transactions as well. All reporting must be carried out through the VeriFactu to AEAT (Agencia Estatal
Weekly Tips : Make your email content error free with Spell check in Zoho Mail
As someone who writes multiple emails a day, we are bound to make both grammatical and spelling errors. Most of them we may not even notice, and even if we do, we may not have the time to correct each one individually when we are in a hurry. So how do
Introducing Enhanced Storage Management
We’re excited to roll out two new enhancements in Zoho Recruit, Subscription Information and Storage Management — designed to give admins complete visibility into subscription details, feature limits, and storage consumption — all from one place inside
how to download all my files
We are in the middle of zoho docs to zoho workdrive migration. I can not access my zoho docs page. I get redirected immediately to a zoho workdrive page. I would like to download all my files so that I have a backup in case something goes wrong with the
Convert Zoho Books SalesOrder - Invoice
Converting a Zoho Books Sales Order into an Invoice Using the SalesOrder Convert API Hello Zoho Developers, Today, we are sharing a simple and effective solution to convert a Zoho Books Sales Order into a Zoho Books Invoice using the SalesOrder Convert
Zoho Expense - Report Templates
Hi Expense Team, I do a recurring trip once every week which has the same cost: Per diem Milage Toll Payment It would be great if there was a feature which allowed me to clone a previously submitted report or create a template reports. This would save
How to add tabular data when execute Add Record API
Hi everyone! I was send api updateRecord follow by this request url : https://people.zoho.com/people/api/forms/json/<formLinkName>/updateRecord with parameters "inputData", "tabularData", "recordId". Ex picture below And response success: But. When I
Tip #51- Centralized Contact Management for Better Remote Support- 'Insider Insights'
For our final topic of November, we’re diving into one of the most helpful features in Zoho Assist, the Contacts section on Zoho Assist;s dashboard. Whether you’re managing multiple clients, tracking past sessions, or simply looking to streamline your
Using gift vouchers
We would like to be able to offer a limited number of gift vouchers, of varying values, to our customers, and are looking for the best way to do this. We have looked at Coupons and Gift Certificates, but neither seem to fit the bill perfectly. Coupons:
Option to Customize Career Site URL Without “/jobs/Careers”
Dear Zoho Recruit Team, I hope you are doing well. We would like to request an enhancement to the Career Site URL structure in Zoho Recruit. In the old version of the career site, our URL was simply: 👉 https://jobs.domain.com However, after moving to
Say Hello to Telephony in Zoho FSM
Zoho FSM now brings complete telephony support so your team can manage inbound and outbound calls without switching tabs. Faster responses, smarter routing, and total call visibility—all in one place. Choose the telephony setup that works for you Zoho’s
Zoho Sign - Zoho CRM extension upgrade
Hi everyone, We've updated Zoho Sign extension for Zoho CRM with significant internal changes. Impact on existing Zoho Sign extension users Users using the extension without customization If you are using the integration without implementing Zoho Sign's
Sent mail sort by date disappeared
Hello, We used to be able to sort the emails by date in the sent folder, but this feature has recently disappeared. Can we bring it back?
E-Invoicing in Belgium with Zoho Inventory
Starting January 1, 2026, Belgium is introducing mandatory electronic invoices (e-invoicing) for all B2B transactions between VAT-registered businesses. Invoices and credits notes must be exchanged in a prescribed digital format. How E-Invoicing Works
Employee ID is not correct in get records api V2 for leave
Hi Team, We are facing an issue when calling the Get Records API V2. The employee.id returned in the response is not the actual employee record ID in Zoho People. As a result, our integration is forced to make an additional Get Record API call for every
Formatting Mailing Labels
I want to use the "Print Mailing Labels" function on the drop down list, but I am not seeing a way to change the formatting on the mailing labels. At the moment, the information that appears on the mailing labels ARE NOT mailing addresses, but random
Zoho People. Updating TabularData
I am trying to update tabular data in the record. I always have the same response. I have checked many times. Section ID is correct. May be something wrong with request structure itself. Can someone help me. Body content type: form urlencoded query params
Canvas View - Print
What is the best way to accomplish a print to PDF of the canvas view? Latest update (27th November 2025): We are excited to announce that the Canvas Print View is now available! We encourage you all to try it out and share your feedback with us. Learn
Next Page