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

    • Zoho Sites - contact us form

      I have added a contact us form to my website. I wanted to change the layout so I deleted the section of Contact Us form. When I again try to add the section of Contact Us form, it shows error that "This form already exists on this page."  I am unable

    • switching from POP3 to IMAPI do I need to change settings in Web email?

      hi so I am using Outlook with My Zoho mail, also have Verizon email /AOL. they no longer support POP3 and said imapi is much better, so I want to switch my ZoHo to imapai. I googled and it said i need to change it in my account....i looked at my account

    • What functionality is new in the Z025 Spaces UI dashboard compared to the previous Zoho One dashboard?

      My company is interested in creating a revamped dashboard this coming year, and are trying to weigh different platform options. The new Spaces UI is said to be a more "feature-rich" dashboard experience than the previous. Could a developer please explain

    • Collections Management: #5 Convenience on Offer, using Self-Checkout

      "Is this the right page? Oh, now, it wants my address again. Why am I being redirected?" These were the exact thoughts running through Karan's mind as he tried to subscribe to an application he genuinely liked. He clicked "Buy Now", expecting a quick

    • Tip #50- A Closer Look at the Unattended Access Dashboard- 'Insider Insights'

      Having complete visibility and quick access to everything you need certainly makes managing multiple remote devices a lot easier, and that is precisely what the Unattended Access Dashboard in Zoho Assist is designed to offer. Once you go to the Unattended

    • How to update custom multi-user field in Zoho Projects?

      I'm trying to update custom multi-user fields in Zoho Projects via a Deluge function in CRM. The code I have so far is below. It works for updating standard project fields and single-line custom fields, but it does not work to update multi-user fields.

    • Tip of the Week #75– Manage your social media messages from a single shared inbox.

      Are you tired of jumping between apps or browser tabs to reply to your business's Facebook and Instagram DMs? Handling customer messages on social media might seem simple, but switching between multiple platforms can easily lead to lost messages, duplicate

    • Zoho Map integration tasks have changed - you need to "Locate all instances of Zoho Map integration tasks in your Deluge scripts by searching for the v1 marker... before 16 January 2026"

      The Zoho Map deluge integration task has been changed (as at 21 October 2025) to provide a more structured, JSON-like response. This change affects all three Zoho Map integration tasks (Geocode, Reverse Geocode, and Distance Between). More details can

    • Using files from Zoho CRM in Gemini/ChatGPT/Claude

      Hi all, I’ve got subscriptions to Gemini and a few other AI tools which I use for tasks like data enrichment, email composition, etc. In our workflow, we often receive various documents from clients — such as process workflows, BRDs/requirement documents

    • Zoho Analytics & Zoho Creator - Modified Time value

      I'm trying to use the Zoho Creator system field 'modified time' in Zoho Analytics, but it's consistently showing 12 hours 'out' In Zoho Creator In Zoho Analytics Is this a constant difference that I just need to correct with a timezone change - or is

    • Zoho CRM - Option to create Follow-Up Task

      When completing a Zoho CRM Task, it would be very helpful if there was an option to "Complete and Create Follow-Up Task" in the pop-up which appears. It could clone the task you are closing and then show it on the screen in edit mode, all the user would

    • Portal For Different Apps

      I found some older threads on this but didn't see anything very recent. I'm new to Zoho One so forgive me if my terminology is off a bit. I was hoping set up a single point of entry into Zoho One. So, many of the apps could be found in one single place

    • Calls undetected

      Zoho Voice records indicate my last call ended at 6:00 PM. All incoming and outgoing calls occurred between 6:00 PM and 7:00 PM.

    • Unable to Select Authenticated Domain as Sender

      We’ve already authenticated our domain, but it’s still not appearing in the sender list when we try to run a campaign. Could you please check what might be causing this issue?

    • Zoho Projects - Show Task List as dropdown field on Task records

      Hi Project's Team, I noticed today that there is no field on a task record related to the task list it belongs to. A dropdown would be helpful for quickly moving tasks between lists while in a task. I know that you can go to "Other Actions" and choose

    • My followed tickets extension is not working under the All departments view

      Hi. I've installed the My followed tickets extension. However, when I try to open the extension under the all departments view, I get the following message: 'Sorry, this extension is not supported in the All Departments view.' How can I solve this p

    • Ticket Time Entry to Timesheet

      The title just about sums it up. I have searched here and not found anything relevant, but If I overlooked, then please set me straight.  We have staff that do nothing but close tickets in desk all day long. These tickets represent their timesheet. Is there a way to have this information sync or for a tech to go into their timesheet themselves and sync it with their tickets of the same timeframe?? We waste a ton of time doing timesheets and the old "Clock in/Clock out" isnt detailed enough for us!!

    • Calls undetected.

      The call is not showing on the call log.

    • Calls undetected

      Zoho is not reading calls made.

    • Missing information data Zoho inventory

      there some missing data in Zoho inventory connection. pick list stock counts bin location we have requested it via mail and the support team doesn’t gove feedback. has anyone achieve to get these info or to ask other ya les

    • Calendar Events Issues

      Not able to view scheduled events on my calendar

    • Extensions 101 webinar series: Build, integrate, and monetize with extensions

      Attention developers! Are you ready to take your extension development skills to the next level? We're excited to bring back the Extensions 101 webinar series with an expanded lineup of Zoho products and an introduction to more platform features. Last

    • Where are recordings stored?

      I have hosted a couple of test meeting, used the "record" button to start and stop the recording but I am unable to find where are those recordings saved?  Can anybody help? Thanks

    • Zoho Desk's integration with Microsoft PowerBI delivers advanced analytics insights

      Hello everyone, Gaining advanced insights through reports and dashboards is one of the critical requirements of every business. In addition to key metrics tracked in Zoho Desk, such as agent performance, SLA adherence, and ticket lifecycle, businesses

    • IMAP error message in Zoho mail

      I cannot send emails today. Everything fine for years until today. Get a message: "You are yet to enable IMAP for your account. Please contact your administrator". Does anyone know how to correct this?

    • IMAP stopped working today

      Hello! I've been a paid customer for more than 10 years, IMAP was always working fine. But today this is the error I've got on my iPhone: I've tried toggling the IMAP for my account (Mail -> Settings -> Mail accounts) off and on again, but that did not

    • Are custom portals accessible on the Zoho learn smartphone app?

      In other words, can users external to my organisation, once signed up, use the app in the same way as internal users? Thanks

    • Conditional Layouts On Multi Select Field

      How we can use Conditional Layouts On Multi Select Field field? Please help.

    • Multiple columns in a form

      I am evaluating Zoho Creator. However, I am seeing almost no layout control on a form.  Just a basic 1 or 2 column format that is then imposed on the entire form.  That's not going to work for many, many real world cases. We need multiple columns per line, and we need each line/section to occupy a single column or be able to span the columns.   Someone please tell me that I'm missing something and the capability is actually there.  

    • Global search

      Hi! I think it would be great to have a global search that would give you results from all records of a database, no only for a single field of a single form as we have now. Thanks!

    • Any insights about API/v2? Having problem for a while.

      I don't know why it is throwing a 404 error, my report name is correct. Has someone had this issue and how you fix it?

    • Edit QR code with redirect to form

      Guten morgen, wir haben ein Formular Reklamation_erstellen. Dort soll ein QR Code erstellt werden, der im Lieferschein angezeigt wird. Beim Scannen auf dem soll das jeweilige Formular zum BEARBEITEN geöffnet werden. Leider bekomme ich es nur so hin, dass

    • Getting all the ingredients together for baking an app

      Good day everyone. After reading a lot of the help docs and watching videos, I now started on my app. To prevent hours and hours wasted on going down the wrong track, I would like some clarification on the following. But first some background: I have

    • Help Needed with Configuring ZC Microservice

      I'm attempting to create a simple microservice, but am running into problems with scope and auth. Using Custom API Builder, here's my setup: 1. Method: GET 2. Auth: OAuth2 3. User Scope: All users 4. Response: Standard 5. Function: A function that returns

    • Creator Simplified #10: Predefine Form Field Values and Make Them Read-Only for Users

      Hey Creators, Ready for this week's tip in the Creator Simplified series? Today, we will explore how to have read only fields in a form. Use Case: Assume a scenario where the default value for a Department field needs to be English Literature, but you

    • Zoho Mail : Email Outgoing Blocked

      I suddenly received the following message yesterday. I cannot send any mail. Please resolve as soon as possible, I cannot work without sending email. Dear User, We regret to inform you that your email outgoing has been blocked and you will not be able

    • Creator and Tables

      Good day. I am trying to create my first application. I have imported my data into Tables and am creating my app in Creator. I do not see my tables and cannot see how to write forms data to a table. Even the Workflow just uses the form. In one of the

    • customer Name and address details

      i created one application there is no customer details in that . how to add customer details and

    • Recalculate every row in the subform

      Hello, Can anyone help me with a script, please? I have an issue. Sometimes it happens, that in a multi row subform one of the rows show an incorrect row total value. Not really understand how it can happen, if I have a 20 row subform, 19 rows show correct

    • Creating Repeat Forms that remove redundancies

      I wanted to understand if you can make multi-layer forms that reduce the need for users to input information in again and again. We want a form that our suppliers fill out per ingredient they sell, and the end result should have the Ingredient (Section

    • Next Page