Kaizen #191: Implementing "Login with Zoho" using Python SDK

Kaizen #191: Implementing "Login with Zoho" using Python SDK

      
Welcome back to another week of Kaizen!!

This week, we are diving into how to implement secure user authentication using Login with Zoho and integrate it with Zoho CRM through our Python SDK.

To ground this in a real-world scenario, we will look at how Zylker Academy, a training institute offering web design and development courses, uses an internal portal that connects directly to Zoho CRM. This setup allows course coordinators to manage student data without maintaining a separate backend database.

Zylker receives frequent student enquiries and uses Zoho CRM to manage all related information. Every course coordinator, academic advisor, and support staff member who needs access to student information is added as a user in Zoho CRM, with access permissions aligned to their role. Instead of using Zoho’s interface directly, Zylker’s team works through a custom internal web portal, tailored to their workflow. This portal connects directly to Zoho CRM, reading from and writing to it, but does not have its own database.

But before this portal can access any CRM data, it must authenticate itself securely. Every time a user opens the portal, they must log in with their Zoho account. Once authenticated, they will be granted access to the CRM modules and records they are authorized to work with. That is where Login with Zoho comes in.

What is "Login with Zoho"?

Login with Zoho is Zoho’s implementation of the OAuth 2.0 Authorization Code flow. It allows applications to authenticate users and access their Zoho CRM data without ever handling their passwords.
Instead of asking users for their Zoho credentials directly, the app redirects them to Zoho’s login screen. Here is how it works:
  1. The app redirects the user to Zoho’s login page.
  2. The user logs in and approves the requested permissions (scopes).
  3. Zoho sends back an authorization code.
  4. The backend exchanges this code for access and refresh tokens.
  5. These tokens are used to make authenticated API calls.
This flow ensures that users maintain full control over their data. They can revoke access at any time, and your application never handles or stores passwords. 
In Zylker’s case, every time a coordinator opens the portal, they are prompted to log in with their Zoho account. Once authenticated, they can immediately begin working with student records—all backed by Zoho CRM.

Use Case Implementation: Zylker’s Student Management Portal

To demonstrate how this login flow works, we have built a stripped-down version of Zylker's portal:
  • A front-end form to enter and view student data
  • A backend server that interacts with Zoho CRM via the Zoho CRM Python SDK
The application includes a simple form for capturing student details—name, college, course, email, and phone number. Submitted data is treated as a Lead in Zoho CRM.
The app allows users to:
  • Add new leads
  • View a list of all registered leads
  • Edit an existing lead’s information
  • Delete records if necessary
All actions go straight to Zoho CRM using its Python SDK. But before any of this can happen, the user must complete the login flow.

Sample Project Structure

Before going into the implementation details, let us briefly define the components of the project.

Frontend
The frontend is a simple static web interface built with HTML, CSS, and JavaScript. It runs in the browser and handles user interactions and triggers backend API calls. These are the main files:
  • index.html : Main UI for login, data entry, and record viewing.
  • script.js : Contains the client-side logic to trigger login, submit data, and render records.
  • redirect.html :  A minimal page used to capture the authorization code returned by Zoho after login.
The frontend is served using any static server (e.g., Live Server in VS Code) and runs on http://localhost:5501/ in our example. 
Download the files from here.
Configuration Notes:
  • In script.js, update the redirect_url value in the login request to match your actual domain or port if you’re not using localhost:5501.
  • Ensure the URL in the Zoho API Console matches this redirect URI and port.
Backend
The backend is a Python server that handles all interactions with Zoho CRM via the Python SDK. It includes:
  • server.py : A custom HTTP server that:
    • Generates the Zoho login URL
    • Exchanges the authorization code for tokens
    • Initializes the SDK
    • Exposes endpoints like /create, /get_records, /update, and /delete
  • record.py : Contains functions to create, fetch, update, and delete records in CRM modules like Leads. Each function uses the Zoho Python SDK methods to perform a specific operation.
This server runs on http://127.0.0.1:8085/ in our example. 

Download the files from here.
Configuration Notes:
  • In server.py, replace the client_id with your actual client ID from Zoho's API Console.
  • In record.py, replace the client_secret with your actual client secret.
  • If required, change the front-end server’s host and port in the run() function at the bottom of server.py:
    def run(server_class=HTTPServer, handler_class=SDKInitialize, port=xxxx):

Sample project flow

      

Step 1: Register the application with Zoho API console

To initiate the login process, you need to register your application on the Zoho API Console. This is a one-time setup that provides your app with a Client ID and Client Secret, both of which are required to authenticate users and exchange authorization codes for tokens.
To register your application:
We will be using these values in the backend script (server.py)  that handles token exchange.

NotesNOTE: To support users from multiple data centres, make sure to enable multi-DC support for your application. You can do this by going to your app’s settings in the Zoho API Console and turning on the Multi-DC option.

Step 2: Implementing the login flow

Here is a walkthrough of the flow implemented in the project:

1. Page loads and triggers login

When a user opens the portal, the frontend automatically initiates the login sequence. It first makes a call to the backend to retrieve the Zoho authorization URL. 

In index.html, this triggers getRecords() on page load:
  1. <body onload="getRecords();">
In script.js, getRecords() calls the login() function:
  1. async function getRecords() {
  2.     login();
  3. }
The login() function sends a request to the backend to get the Zoho OAuth authorization URL.

2. Backend builds login URL

The backend responds with an OAuth URL that includes:
  • Your client ID
  • Scopes like ZohoCRM.modules.ALL
  • The redirect URI
In server.py, under do_GET, the /login endpoint generates the OAuth URL:
  1.    if parsed_url.path == '/login':
  2.             redirect_url = query_params.get('redirect_url', [''])[0]
  3.             scope = "ZohoCRM.settings.fields.ALL,ZohoCRM.modules.ALL,ZohoCRM.users.READ,ZohoCRM.org.READ"
  4.             url = "https://accounts.zoho.com/oauth/v2/auth?scope=" + scope + "&client_id=" + self.client_id + \
  5.                   "&redirect_uri=" + redirect_url + "&response_type=code&access_type=offline"
  6.             self._set_headers()
  7.             # Send response
  8.             response = {"url": url, "redirect_url": redirect_url}
  9.  self.wfile.write(json.dumps(response).encode('utf-8'))
Once the frontend (script.js) receives the login URL, it opens it in a popup window.
  1. const response = await fetch('http://127.0.0.1:8085/login?redirect_url=http://127.0.0.1:5501/redirect.html');
  2. const data = await response.json();
  3. const popup = openCenteredPopup(data.url, "PopupWindow", 600, 400);
Here's an example of the Zoho OAuth authorization URL format:
      scope=ZohoCRM.modules.ALL&
      client_id=YOUR_CLIENT_ID&
      response_type=code&
      access_type=offline&
      redirect_uri=YOUR_REDIRECT_URI

3. User logs in on Zoho

The user logs in with their Zoho credentials and is prompted to approve the app's access. Once they approve, Zoho redirects them to the specified redirect URI along with an authorization code and location parameter. The location parameter indicates which data centre the user belongs to.

4. Frontend captures the authorization code

The redirect page, a minimal HTML file (redirect.html),  reads the URL parameters and stores them in localStorage, then closes the popup:
  1. function setAccessToken() {
  2.     var hashProps = getPropertiesFromURL();
  3.     if (hashProps) {
  4.         for (var key in hashProps) {
  5.             if (hashProps.hasOwnProperty(key)) {
  6.                 localStorage.setItem(key, hashProps[key]);
  7.             }
  8.         }
  9.     }
  10.     setTimeout(function () { window.close(); }, 0);
  11. }

5. Token exchange and SDK initialization

Once the popup window is closed, the main window retrieves the authorization code and location and sends them to the backend’s /initialize endpoint.
In script.js:
  1. var code = localStorage.getItem("code");
  2. var location = localStorage.getItem("location");
  3. initialize(code, location, data.redirect_url);
  4. .
  5. .
  6. async function initialize(code, location, redirect_url) {
  7.     const response = await fetch('http://127.0.0.1:8085/initialize?code=' + code + '&location=' + location + '&redirect_url=' + redirect_url);
  8. }
In server.py, the /initialize endpoint handles SDK initialization:
  1. elif parsed_url.path == '/initialize':
  2.     code = query_params.get('code', [''])[0]
  3.     location = query_params.get('location', [''])[0]
  4.     redirect_url = query_params.get('redirect_url', [''])[0]
  5.     LeadsRecords().init(self.client_id, code, location, redirect_url)
In record.py, the SDK is initialized and tokens are stored.
  1. token = OAuthToken(client_id=client_id,
  2.                    client_secret=client_secret,
  3.                    grant_token=code,
  4.                    redirect_url=redirect_url)
  5. Initializer.initialize(environment=environment,
  6.                        token=token,
  7.                        logger=logger,
  8.                        store=store)  # FilePersistence or custom store
This exchanges the authorization code for:
  • An access token (valid for one hour)
  • A refresh token (used to get new access tokens)
These tokens are saved in a local file (sdk_tokens.json). This is configured using Zoho’s FilePersistence class during SDK initialization 

How are tokens linked to users?

The SDK maps each access and refresh token pair to a unique user-organization combination. This means tokens generated for different organizations by the same user are stored separately. Likewise, if a user generates new tokens for the same organization, the SDK updates the existing tokens instead of creating duplicates. This ensures that API calls always use the correct tokens tied to the authenticated user and their organization. 

To enable this mapping, the SDK retrieves the user and organization information in the background. This requires the appropriate scopes to be included during authentication, ZohoCRM.users.READ and ZohoCRM.org.READ. Without these scopes, the SDK cannot identify the user-org combination correctly, which can lead to multiple token entries for the same user. That is why, in our sample project, we have included these scopes explicitly in the server.py file during the SDK initialization.

Once the SDK is initialized, the user is logged in, and the app can begin making CRM API calls on their behalf.


Step 3: Accessing Zoho CRM

Once the user is authenticated and the Zoho SDK is initialized on the backend, the frontend can call custom backend endpoints like /create or /get_records. These endpoints use the authenticated SDK instance to make CRM API calls on behalf of the user.
  • GET /get_records?module=Leads : View all students
  • POST /create?module=Leads : Add new student
  • PUT /update?module=Leads&id=... : Edit existing entry
  • DELETE /delete?module=Leads&id=... : Remove existing entry

Deploying the sample project

To run this application, you will need two components:
  1. A frontend server to serve your HTML files (index.html, script.js, redirect.html). This can be done using any static web server (e.g., Live Server in VS Code).
  2. A Python backend server that handles login, token storage, and CRM API communication. You can run it using:
    python server.py
In the given example, both servers communicate over localhost. You should set your redirect URI accordingly when registering your app in the Zoho console.

Conclusion

Login with Zoho is a secure, OAuth-based mechanism that allows users to authorize your application to access their Zoho CRM data. In this example, we built a real-world use case, a student portal for Zylker Academy, that authenticates users and interacts with CRM directly using the Zoho CRM Python SDK.
By walking through the entire flow, you now understand:
  • Why OAuth is essential for secure CRM access
  • How to register an application in Zoho
  • What the login and token exchange flow looks like
  • How to implement "Login with Zoho" in your applications

What is next?

In this project, we have used a simple file persistence method to store the token files. But in a real world scenario, this may not always meet your business requirements. In next week's Kaizen, we will implement custom token persistence instead of file persistence in the current project. We will explain how to implement this using SQLite, In-Memory and List DBs. With that, you will be equipped to implement a persistence method that fits your application architecture and deployment environment.

We hope that you found this useful. If you have any queries, let us know the comments below, or send an email to support@zohocrm.com. As always, we would love to hear from you!!

Stay tuned for next week's Kaizen : Implementing Custom Token Persistence 


Download Links:
Further Reading:


      Zoho Campaigns Resources


        • Desk Community Learning Series


        • Digest


        • Functions


        • Meetups


        • Kbase


        • Resources


        • Glossary


        • Desk Marketplace


        • MVP Corner


        • Word of the Day


        • Ask the Experts


          • Sticky Posts

          • 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.

          • Kaizen #226: Using ZRC in Client Script

            Hello everyone! Welcome to another week of Kaizen. In today's post, lets see what is ZRC (Zoho Request Client) and how we can use ZRC methods in Client Script to get inputs from a Salesperson and update the Lead status with a single button click. In this

          • Kaizen #222 - Client Script Support for Notes Related List

            Hello everyone! Welcome to another week of Kaizen. The final Kaizen post of the year 2025 is here! With the new Client Script support for the Notes Related List, you can validate, enrich, and manage notes across modules. In this post, we’ll explore how

          • Kaizen #217 - Actions APIs : Tasks

            Welcome to another week of Kaizen! In last week's post we discussed Email Notifications APIs which act as the link between your Workflow automations and you. We have discussed how Zylker Cloud Services uses Email Notifications API in their custom dashboard.

          • Kaizen #216 - Actions APIs : Email Notifications

            Welcome to another week of Kaizen! For the last three weeks, we have been discussing Zylker's workflows. We successfully updated a dormant workflow, built a new one from the ground up and more. But our work is not finished—these automated processes are

          Zoho CRM Plus Resources

            Zoho Books Resources


              Zoho Subscriptions Resources

                Zoho Projects Resources


                  Zoho Sprints Resources


                    Zoho Orchestly Resources


                      Zoho Creator Resources


                        Zoho WorkDrive Resources



                          Zoho CRM Resources

                          • CRM Community Learning Series

                            CRM Community Learning Series


                          • Tips

                            Tips

                          • Functions

                            Functions

                          • Meetups

                            Meetups

                          • Kbase

                            Kbase

                          • Resources

                            Resources

                          • Digest

                            Digest

                          • CRM Marketplace

                            CRM Marketplace

                          • MVP Corner

                            MVP Corner




                            Zoho Writer Writer

                            Get Started. Write Away!

                            Writer is a powerful online word processor, designed for collaborative work.

                              Zoho CRM コンテンツ



                                ご検討中の方

                                  • Recent Topics

                                  • Detailed Balance Sheet for tax preparer

                                    I'm using the free edition of Zoho Books. My tax preparer is asking for "detailed" Profit & Loss and Balance Sheet reports which include all the activity and transactions within the various categories. The default reports do not include these details.

                                  • Sending automated messages that appear in the ticket's conversation thread

                                    Good morning, esteemed Zoho Desk community, warm greetings Today I am here to raise the following problem, seeking a solution that I can implement: I need to implement an automation that allows me to send reminder messages to customers when I am waiting

                                  • Payment Card or Identity form-fill from Vault?

                                    Hello! I'm working on replacing Bitwarden with Vault and one issue I've run into is that I can't find any option to fill address and payment forms from Payment Card or Identity info that has been saved in Vault. Is there a way to do this? Is it a planned

                                  • Ability to add VAT to Retainer Invoices

                                    Hello, I've had a telephone conversation a month ago with Dinesh on this topic and my request to allow for the addition of VAT on Retainer Invoices.  It's currently not possible to add VAT to Retainer Invoices and it was mutually agreed that there is absolutely no reason why there shouldn't be, especially as TAX LAW makes VAT mandatory on each invoice in Europe!   So basically, what i'm saying is that if you don't allow us to add VAT to Retainer Invoices, than the whole Retainer Invoices becomes

                                  • Time Log Reminder

                                    Tracking the time spent on tasks and issues is one of the most important functions of a timesheet. However, users may forget to update the time logs because they have their own goals to achieve. But, time logs must be updated at regular intervals to keep

                                  • [Early-access] Introducing Zoho's CommandCenter - Cross-Zoho business process automation

                                      Resources to help Webinar recording | Documentation  Feature Restrictions Currently available on early-access only for US data center accounts Features Role CommandCenter as a Service uses signals across Zoho services to propel the movement of records

                                  • Tip #58- Accessibility Controls in Zoho Assist: Learning- 'Insider Insights'

                                    Learning should be clear and interruption-free for everyone. Timely feedback plays an important role in helping users understand actions as they happen, without breaking their focus. In this post, we’ll explore the final section of Accessibility: Learning.

                                  • ZIA "Generate Content" action doesn't have contexual data from the ticket

                                    "Generate Content" action doesn't have contexual data from the ticket. I try to get AI to help me with this ticket but it doesn't seem to have any ticket information as context. Although the ticket has a lot of information in it.

                                  • Zoho Desk - Zoho FSM Integration issue on Mobile and iPad

                                    Hello Team, I am trying to create a Work Order (WO) using the Zoho FSM integration (Add-on Service) that is integrated with Zoho Desk. The issue is that the integration is not working on mobile devices and iPads. While I am able to create the WO, Request,

                                  • E-File Form 1099 Directly With the IRS From Zoho Books

                                    The Form 1099 filing season has begun, and businesses are required to e-file certain forms with the IRS to report payments made to vendors and contractors. If your business made qualifying payments during the year, you must e-file the appropriate Form

                                  • Suggestions for showing subscribed Topics in CRM (contact record)

                                    We have several Topics set up in ZMA. We also have a sync set up between ZMA and CRM. I'd like to display the subscribed topics on the CRM Contact record. This will allow the Sales team (who uses CRM) to see at a glance what topics a Contact is subscribed

                                  • Replies sometimes creating separate ticket

                                    Sometimes when a customer responds to an email coming from Zoho Desk, instead of adding a reply to the original ticket, a separate ticket is created. This happens even though the response subject line contained the ticket number, and the person responding

                                  • Re-hide fields when option is unselected

                                    Hi all Can anyone help me with this - when I create a 'show' field rule for when a dropdown option is selected, how to I make it so the 'show' option re-hides if that option is no longer selected?

                                  • Custom Fields

                                    There is no way to add a custom field in the "Timesheet" module. Honestly, the ability to add a custom field should be available in every module.

                                  • Consultant-Only Booking Page

                                    Zoho Bookings does not allow for Meeting Type OR Workspace-Wide booking pages to be turned off. This is detrimental to organizations that have territory-based or assigned accounts, because if prospects can go to these booking pages and either select the

                                  • Call result pop up on call when call ends

                                    I’d like to be able to create a pop up that appears after a call has finished that allows me to select the Call Result. I'm using RingCentral. I have seen from a previous, now locked, thread on Zoho Cares that this capability has been implemented, but

                                  • Custom Sorting based on other columns in table

                                    I need the ability to apply custom sorting to a text-based dimension in the X axis where the sorting is based on another column in the table. For example, I have a chart report where the X axis is a text label. I would like to be able to sort those text

                                  • Feature Request: Enable Custom PDF Layout Editor for All Modules (Including Package Slips)

                                    Hello Zoho Community and Product Team, I am writing to share a suggestion that would significantly enhance the customization capabilities within Zoho Books. We all appreciate the power of the Custom PDF Layouts (the "New" template engine) that allows

                                  • Is there a way to invoke deluge function from within a widget?

                                    Hi! I have custom functions in deluge and I was wondering whether there is any way to call this function through a widget? Something like on click of a button inside a widget, run the deluge custom function. Would this be possible?

                                  • Can a default task Priority be set?

                                    The "Priority" field in the Task layout does not allow a default to be set. Is there another way of doing it? Because the current default is "None" and the Zoho Kanban board design has selected this field as critical information to surface by including

                                  • Adding a threshold to a line chart based on date range

                                    I have a line chart that is tracking a percentage over time. It also has a filter for 50 different clients. I would like to create a threshold that is based on a portion of the date range. As I understand it, this would be done by adding a column to the

                                  • Resize Signature field dynamically

                                    On the tablet, it is perfect. But on smaller mobile devices and PCs, both web and application, it is too small for people to sign. Is there any plan to make the signature field size dynamically in the future update?

                                  • Super Admin Logging in as another User

                                    How can a Super Admin login as another user. For example, I have a sales rep that is having issues with their Accounts and I want to view their Zoho Account with out having to do a GTM and sharing screens. Moderation Update (8th Aug 2025): We are working

                                  • Zoho Creator Application - New User Not able to access the application

                                    In Zoho Creator, The newly added user not able to access the " Added Application" - User has received the Invitation Email, but while clicking "confirm Account" in the invitation Email, the following error message has appeared. "Sorry! you cannot accept

                                  • Deleting Salutation Field

                                    We have updated our lead input screen and 'Salutation' has appeared. This is not visible in the 'Edit Pgae Layout' screen so cannot be moved to 'List of Removed Fields'  Salutation is visible in the list in 'Customization - Fields' however I can only 'Edit' or 'Replace' I cannot delete and I do not need this field on my lead input screen.  Please can you advise how to get rid of this.  Screen shots can be provided if needed.  Thank you Tasha

                                  • Auto-Generate & Update Asset Serial Numbers using a custom function (Assets Module)

                                    Hello Team, I’ve been working on a script to automate one of our processes in Zoho FSM, and the core functionality has been successfully implemented. However, I’m encountering an issue related to serial number allocation, which is not working as expected.

                                  • Zoho Mail iOS app update: Access Delegated Mailbox.

                                    Hello everyone! You can now access the delegated mailbox from within the iOS version of the Zoho Mail app. To access the delegated mailbox: Open the Zoho Mail app. Go on to the 'Email' module. Tap the profile picture. Choose the delegated mailbox Please

                                  • How to convert Lead's country field from Text to Pick List

                                    Hi, I would like to change the default country field in ZCRM from text to pick list. It looks like not I can't delete default country field and recreate it as pick list nor can i create an new custom field country because such a label belong to default field. So what do I have to do? Any ideas? L

                                  • How create a draft via workflow?

                                    I wish to create a workflow rule for specific emails that creates a draft response - not an automatic email reply, but just a draft with a set response ready to be verified by an agent who can then manually select recipients. Alternatively, the workflow

                                  • Function #51: Transaction Level Profitability for Quotes

                                    Hello everyone, and welcome back to our series! In a previous post, we shared a custom function that could determine the profitability of a Sales Order. Today, we are presenting a similar function that calculates the profitability of a Quote. The setup

                                  • New feature: Invite additional guests for your bookings

                                    Hello everyone, Greetings from Zoho Bookings! We are happy to announce the much-awaited feature Guest Invite, which enhances your booking experience like never before. This feature allows additional participants to be invited for the bookings to make

                                  • Improved Contact Sync flow in Google Integration with Zoho CRM

                                    Hello Everyone, Your contact sync in Google integration just got revamped! We have redesigned the sync process to give users more control over what data flows into Google and ensure that this data flows effortlessly between Zoho CRM and Google. With this

                                  • الخصم على مستوى فاتورة المبيعات

                                    السلام عليكم ورحمة الله وبركاته مطلوب في إنشاء خصم على مستوى فاتورة المبيعات وليس على مستوى البند أريد معرفة الطريقة؟

                                  • VAT and Taxes option not available

                                    Dear ZOHO Team , The VAT and Taxes options in my ZOHO books account not available,I tried to find how to enable or check the way to use this option but unfortunately couldn't find it anywhere ,I'm in UAE ,kindly let me know what to do to solve this issue

                                  • Default Tagging on API-generated Transactions

                                    If one assigns tags to an Item or Customer, those tags get auto-populated in each line item of an Invoice or Sales Order when one creates those documents. However, if one creates the Sales Order or Invoice via the API (either directly coding or using

                                  • Direct Feed (Bank)

                                    Is Direct feed integration for AlRajhi and ADCB bank supported by Zoho Books in GCC/Saudi

                                  • Sales Order, Invoice and Payment numbers

                                    Hi zoho friends, it is me again, the slow learner. I'm wondering if there is a way to have it so the Sales order, invoice and payment numbers are all the same? It would be easier for me if they were the same number so there is not so many reference numbers

                                  • Customer Satisfaction (CSAT) Report

                                    From data to decisions: A deep dive into ticketing system reports The customer satisfaction (CSAT) report helps teams understand how customers feel about their support experience, identify service gaps, and continuously improve the help desk. It turns

                                  • Timeline Tracking Support for records updates via module import and bulk write api

                                    Note: This update is currently available in Early Access and will soon be rolled out across all data centers (DCs) and for all editions of Zoho CRM. The update will be available to all users within your organization, regardless of their profiles or roles.

                                  • Shifts in Zoho People vs Zoho Shifts?

                                    Hello Zoho People Team, We hope you are doing well. We are evaluating the Shifts functionality within Zoho People and comparing it to the standalone Zoho Shifts product. We’ve encountered comments and discussions suggesting that the Shifts feature inside

                                  • Next Page