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:

    • Sticky Posts

    • 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

    • Kaizen #152 - Client Script Support for the new Canvas Record Forms

      Hello everyone! Have you ever wanted to trigger actions on click of a canvas button, icon, or text mandatory forms in Create/Edit and Clone Pages? Have you ever wanted to control how elements behave on the new Canvas Record Forms? This can be achieved

    • Kaizen #142: How to Navigate to Another Page in Zoho CRM using Client Script

      Hello everyone! Welcome back to another exciting Kaizen post. In this post, let us see how you can you navigate to different Pages using Client Script. In this Kaizen post, Need to Navigate to different Pages Client Script ZDKs related to navigation A.

    • Recent Topics

    • Writer update results in BitDefender blocking it as malware

      After updating Writer to latest update, Bitdefender blocked the app and writer no longer runs.

    • Missing Import Options

      Hello, do I miss something or is there no space import option inside of this application? In ClickUp, you can import from every common application. We don't want to go through every page and export them one by one. That wastes time. We want to centralize

    • Zoho CRM Portal Field Level Permission Issue

      Hi Support Team, I am using the Zoho CRM Portal and configuring field-level editing permissions. However, we are unable to restrict portal users from editing certain fields. We have created a portal and provided View and Edit (Shared Only) access for

    • 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

    • Custom Fonts in Zoho CRM Template Builder

      Hi, I am currently creating a new template for our quotes using the Zoho CRM template builder. However, I noticed that there is no option to add custom fonts to the template builder. It would greatly enhance the flexibility and branding capabilities if

    • Collaboration with customers made easy with Zoom Meeting and Zoho Desk integration

      Hello everyone! We are happy to announce that you can now integrate your Zoho Desk account with Zoom Meeting. The integration bridges the gap between digital communication and human connection, empowering teams to deliver timely support when it matters

    • CRM Canvas - Upload Attachments

      I am in the process of changing my screens to Canvas.  On one screen, I have tabs with related lists, one of which is attachments.  There doesn't appear to be a way to upload documents though.  Am I missing something really obvious?  Does anyone have

    • TrueSync regularly filling up my local disk

      Seems that WorkDrive's TrueSync randomly starts filling up my local hard drive space. None of the folders have been set as "Make Offline" but still it seems to randomly start making file offline. The settings of the app is so minimal and is of no real

    • Kaizen #194 : Trigger Client Script via Custom buttons

      Hello everyone! Welcome back to another interesting and useful Kaizen post. We know that Client Scripts can be triggered with Canvas buttons and we discussed this with a use case in Kaizen#180. Today, let us discuss how to trigger Client Script when a

    • [Webinar] A recap of Zoho Writer in 2025

      Hi Zoho Writer users, We're excited to announce Zoho Writer's webinar for January 2026: A recap of Zoho Writer in 2025. This webinar will provide a recap of the features and enhancements we added in 2025 to enhance your productivity. Choose your preferred

    • Picklist field shows "none" as default

      Hello, Is there an option to avoid showing "none" as the default value in a picklist field? I also don't want to see any option displayed. My expectation is to have a blank bar, and then when I display the drop-down list, I can choose whichever I wa

    • Stage-probability mapping feature in custom module

      Hi, I'm building a custom module for manage projects. I would like to implement the stage-probability feature that Potentials has. Is this possible?

    • Field Description is very small

      Hello, The field Description in the activity is very small. Why don't try open a new window, or a bigger popup, or increase the width of the "popup". Example:

    • StatusIQ

      Please add StatusIQ to data sources. We using site24x7 and StatusIQ together and site24x7 integration is already there. Thanks and regards, Torsten

    • In Zoho People, the Operations buttons are frequently not visible or do not appear consistently.

      In Zoho People, the Operations buttons are frequently not visible or do not appear consistently. We request you to please investigate and address this issue, as it is affecting daily HR operations and user access.

    • Marketing Tip #14: Increase cart value with product bundles

      Bundling products is a great way to increase average order value while giving customers more convenience. Think “camera + tripod + memory card” or “soap + lotion + bath salts.” Bundles make shopping easier and feel like a better deal. It’s a win-win for

    • Problem with Workdrive folders

      I'm having a problem a problem accessing files in a Zoho work drive folder when using the Zoho writer app. The problem folder appears grayed out in the Zoho work drive window in both the online and writer application. However I can open the folder in

    • 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

    • Pre-orders at Zoho Commerce

      We plan to have regular producs that are avaliable for purchase now and we plan to have products that will be avaliable in 2-4 weeks. How we can take the pre-orders for these products? We need to take the money for the product now, but the delivery will

    • Zoho Books' 2025 Wrapped

      Before we turn the page to a new year, it’s time to revisit the updates that made financial management simpler and more intuitive. This annual roundup brings together the most impactful features and enhancements we delivered in 2025, offering a clear

    • Can multiple agents be assigned to one ticket on purpose?

      Is it possible to assign one ticket to two or more agents at a time? I would like the option to have multiple people working on one ticket so that the same ticket is viewable for those agents on their list of pending tickets. Is something like this currently

    • Edit default "We are here to help you" text in chat SalesIQ widget

      Does anyone know how this text can be edited? I can't find it anywhere in settings. Thanks!

    • Can't change form's original name in URL

      Hi all, I have been duplicating + editing forms for jobs regarding the same department to maintain formatting + styling. The issue I've not run into is because I've duplicated it from an existing form, the URL doesn't seem to want to update with the new

    • Feature Request: Sync Leave Tracker to Zoho Mail / Calendar or provide option to download information

      Zoho Leave Tracker offers the option to sync the leave Calendar to Microsoft 365 and Google Calendar. Adding an option to sync to Zoho-Mail Calendar would avoid duplication and add significant value for users. An alternative would be to allow users to

    • Compensation | Salary Packages - Hourly Wage Needed

      The US Bureau of Labor Statistics says 55.7% of all workers in the US are paid by the hour. I don't know how that compares to the rest of the world, but I would think that this alone would justify the need for having an hourly-based salary package option.

    • Multiple currencies - doesn’t seem to work for site visitors / customers

      I am trying to understand how the multiple currency feature works from the perspective of the website visitor who is shopping on my Zoho Commerce site. My site’s base currency is US Dollars (USD) but my store is for customers in Costa Rica and I would

    • Archiving Contacts

      How do I archive a list of contacts, or individual contacts?

    • How do people handle using Outlook and Zoho Project calendar at the same time?

      We have an ongoing problem in our organisation where we use Zoho Projects to plan all of our projects tasks and that also allows us to look forward using the workload report to see which of our consultants are overstretched etc and which are available.

    • 10GB Email Storage Limits in Zoho CRM

      We’ve had Zoho One for almost 5 years and have always synced our emails from Gmail via IMAP… As of late, we’ve run into issues with our emails not syncing, due to being over the 10GB storage cap… What’s very odd is that we haven’t changed a thing? I know

    • Performance is degrading

      We have used Mail and Cliq for about three years now. I used to use both on the browser. Both have, over the past 6 months, had a severe degradation in performance. I switched to desktop email, which appeared to improve things somewhat, although initial

    • How to set page defaults in zoho writer?

      hi, everytime i open the zoho writer i have to change the default page settings to - A4 from letter, margins to narrow and header and footer to 0. I cannot set this as default as that option is grayed out! so I am unable to click it. I saved the document

    • Unable to Send Different Email Templates for Different Documents in Zoho Sign

      Hello Zoho Community, I am facing a limitation with Zoho Sign regarding email notifications sent to customers when a document is sent for signing. Currently, whenever I send any template/document for signing, the email notification that goes to the customer

    • Enable History Tracking for Picklist Values Not Available

      When I create a custom picklist field in Deals, the "Enable History Tracking for Picklist Values" option is not available in the Edit Properties area of the picklist. When I create a picklist in any other Module, that option is available. Is there a specific reason why this isn't available for fields in the Deals Module?

    • ZO25: The refreshed, more unified, and intelligent OS for business

      Hello all, Greetings from Zoho One! 2025 has been a remarkable year, packed with new features that will take your Zoho One experience to the next level! From sleek, customizable dashboards to an all-new action panel for instant task management, we’ve

    • Vault crashes on Android Devices

      Vault is continuously closing after entering the master password on my Android device. After several attempts I get a system message that says there is a bug in the app. I've uninstalled and reinstalled the app, and cleared the app cache, but nothing

    • ¿Cómo puedo configurar las contraseñas creadas bajo una directiva para que nunca caduquen y no aparezcan como caducadas en los informes?

      ¿Cómo puedo configurar las contraseñas creadas bajo una directiva para que nunca caduquen y no aparezcan como caducadas en los informes? La razón por la cual contraseña estas no deben caducar es porque su actualización depende de mi cliente y no de mí.

    • Camera access

      My picture doesn't appear in a group discussion. (The audio is fine.) The guide says "Click the lock icon on address bar," but I can't find it. Advise, please

    • Are static links available

      I'm still using Zoho Meeting in trial mode. My previous webinar software provided a static link, and I made the mistaken assumption that I could send out my link and start a meeting later. Mass confusion, but my fault. With a paid version do you get a

    • Why is Zoho Meeting quality so poor?

      I've just moved from Office 365 to Zoho Workplace and have been generally really positive about the new platform -- nicely integrated, nice GUI, good and easy-to-understand control and customisation, and at a reasonable price. However, what is going on

    • How to print a label from zoho creator app?

      Hello, I would like to print a label from zoho creator app record similar to attached one. Size 74mm x 102mm. I tried record template. It leaves plenty of space around the content and also I couldn't set the height of the page. So it is not printing properly. Could someone please direct me to right direction for this requirement?

    • Next Page