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 #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

    • Recent Topics

    • Form to PDF template

      I am looking to create a Form and when information is inputted, it will merge it into a PDF template we already have. There could be multiple lines in the form and each line inputs information into a new page of a PDF template.

    • Please verify my account

      Hi, We have just launched our website and received media coverage in our country. Hundreds of users are signing up for our platform every day. We would like to send them a welcome email, but we are unable to do so because our ZeptoMail account has not

    • Subject character limit increase

      We have an occasional user case where subject lines exceed 500 characters which is the ZeptoMail imposed limit. While I understand long subject lines are not "best practice", these are particular notification emails with specific information for client

    • Account blocked

      Yesterday I got my Zeptomail account blocked due to too many hard bounces. My account is used exclusively for sending transactional emails (eg. your order has been shipped, a form has been filled, etc) and the sudden blocking impacted hundreds of websites

    • Proactive Alert for Existing Open Tickets per Contact / Account

      Hello Zoho Desk Team, Greetings, and hope you’re doing well. We would like to submit a feature request aimed at improving agent awareness and efficiency when handling tickets in Zoho Desk. Use case When an agent opens a ticket (new or existing), it is

    • Ticket resolution field - can you add links, video, and images?

      Seems like the ticket resolution fields is just a text field. Any plans to add the ability to add links, images...the same functionality in the problem description box? I would like to send the customer a link to a KB article, a link to our Wiki, embed

    • Ticket Resolution - Add rich formatting, screenshots and attachments

      The resolution field only allows plain text at the moment. Many of our resolutions involve posting screenshots as evidence, it would be great for us to be able to have rich text formatting, be able to paste screenshots and add attachments in the solution

    • Kaizen #140 - Integrating Blog feed scraping service into Zoho CRM Dashboard

      Howdy Tech Wizards! Welcome to a fresh week of kaizen. This week, we will look at how to create a dashboard widget that displays the most recent blog post of your preferred products/services, updated daily at a specific time. We will leverage the potential

    • Convert Lead Automation Trigger

      Currently, there is only a convert lead action available in workflow rules and blueprints. Also, there is a Convert Lead button available but it doesn't trigger any automations. Once the lead is converted to a Contact/Account the dataset that can be fetched

    • I'm getting this error when I try to link an email to a deal inside the Zohomail Zoho CRM extension.

      When I click "Yes, associate," the system displays an "Oops!! Something went wrong" error message. I have attached a screenshot of the issue for reference.

    • Zoho Sheet - Desktop App or Offline

      Since Zoho Docs is now available as a desktop app and offline, when is a realistic ETA for Sheet to have the same functionality?I am surprised this was not laucned at the same time as Docs.

    • ZOHO add-in issue

      I cannot connect ZOHO from my Outlook. I am getting this error.

    • Marketing Automation

      L.S. Marketing Automation is and has always been part of the Zoho One bundle - according to the information provided on the Zoho Website. Why when I open Marketing Automation do I get the following message?: "Your trial has expired. We hope you enjoyed

    • What's New in Zoho Analytics - January 2026

      Hello Users! We are starting the year with a strong lineup of updates, marking the beginning of many improvements planned to enhance your analytics experience. Explore the latest improvements built to boost performance, simplify analysis, and help you

    • Translation from Chinese (Simplified) to Chinese (Traditional) is not working. It randomly translated. Google Translate accurately but zoho translate is not working at all

      Hi friends, The newly added language for translation. https://www.zoho.com/deluge/help/ai-tasks/translate.html "zh" - Chinese "zh-CN" - Chinese (Simplified) "zh-TW" - Chinese (Traditional) my original text: 郑这钻 (and it is zh-CN) translated traditional

    • The Social Playbook - January edition: Getting started with content creation

      Social media isn’t just about posting some random content. It’s about why certain content works, how brands stand out, and what makes people pause mid-scroll. The Social Playbook is a monthly community series where we break all of that down. Through real

    • Support for Custom Fonts in Zoho Recruit Career Site and Candidate Portal

      Dear Zoho Recruit Team, I hope you're doing well. We would like to request the ability to use custom fonts in the Zoho Recruit Career Site and Candidate Portal. Currently only the default fonts (Roboto, Lato, and Montserrat) are available. While these

    • Font breakage in Zoho Mail Desktop Lite application for Mac

      Dear Zoho Mail and Workplace Community, With the latest update of macOS Sequoia and macOS Tahoe, there has been font breakages in the email preview of Zoho Mail Desktop Lite application for Mac. This breakage is due to the corruption of the System fonts

    • Nueva edición de "Ask The Expert" en Español Zoho Community

      ¡Hola Comunidad! ¿Te gustaría obtener respuestas en directo sobre Zoho CRM, Zoho Desk u otra solución dentro de nuestro paquete de CX (Experiencia del Cliente? Uno de nuestros expertos estará disponible para responder a todas tus preguntas durante nuestra

    • Automation Series: Auto-Notify External Users on Issue Closure

      Hello Folks! In Zoho Projects, you can notify external issue reporters via email when an issue is marked as Closed. This helps the users avoid manual follow-ups and keeps the reporter updated. In this post, we’ll walk through a simple setup using a Web

    • Turn chat conversations into real action with Integration Blocks in Guided Conversations

      When a Guided Conversation fails, it's usually not because the logic is wrong. They fail because the conversation stops moving. A customer starts a chat with a clear goal: report an issue, check a status, or confirm something. At first, the flow does

    • Basic Mass Update deluge schedule not working

      I'm trying to create a schedule that will 'reset' a single field to 0 every morning - so that another schedule can repopulate with the day's calculation. I thought this would be fairly simple but I can't work out why this is failing : 1) I'm based in

    • click to call feature

      I've Zoho CRM and in that i want click to call feature.

    • Can the Product Image on the Quote Template be enlarged

      Hello, I am editing the Quote Template and added ${Products.Product Image} to the line item and the image comes up but it is very tiny. Is there anyway that you can resize this to be larger? Any help would be great! Thanks

    • Creating Parent Child relationship in Accounts

      We have customers with multiple locations, I setup the HQ as an account, then I setup the different sites marking the HQ as the parent to that location. If I then do a Deal for one of the locations, is there a way to show by looking at the parent account

    • Learner transcript Challenges.

      Currently i am working on a Learner Transcript app for my employer using Zoho Creator. The app is expected to accept assessment inputs from tutors, go through an approval process and upon call up, displays all assessments associated with a learner in

    • Client and Vendor Portal

      Some clients like keeping tabs on the developments and hence would like to be notified of the progress. Continuous updates can be tedious and time-consuming. Zoho Sprints has now introduced a Client and Vendor Portal where you can add client users and

    • #7 Tip of the week: Delegating approvals in Zoho People

      With Zoho People, absences need not keep employees waiting with their approval requests. When you are not available at work, you can delegate approvals that come your way to your fellow workmate and let them take care of your approvals temporarily. Learn more!

    • Admin Tip: Manage sub-domain emails using sub-domain stripping

      As an admin, you may need separate domains for different departments such as sales, support, and marketing. While this approach offers flexibility, creating and managing multiple domains can quickly become overwhelming, especially since each domain requires

    • Quick Copy Column Name

      Please add the ability to quickly copy the name of a column in a Table or Query View. When you right-click the column there should be an option to copy the name, or if you left-click the column and use the Ctrl+C keyboard shortcut it should copy the

    • Ability to Edit YouTube Video Title, Description & Thumbnail After Publishing

      Hi Zoho Social Team, How are you? We would like to request an enhancement to Zoho Social that enables users to edit YouTube video details after the video has already been published. Your team confirmed that while Zoho Social currently allows editing the

    • How do I remove a data source from Zoho Analytics?

      I am unable to find a delte option on a datasource that i put in the system as an error. On teh web it refers to a setup icon but I do not see that on my interface?

    • Add Employee Availability Functionality to Zoho People Shift Module

      Hello Zoho People Product Team, Greetings and hope you are doing well. We would like to submit a feature request to enhance the Zoho People Shift module by adding employee availability management, similar to the functionality available in Zoho Shifts.

    • Bigin, more powerful than ever on iOS 26, iPadOS 26, macOS Tahoe, and watchOS 26.

      Hot on the heels of Apple’s latest OS updates, we’ve rolled out several enhancements and features designed to help you get the most from your Apple devices. Enjoy a refined user experience with smoother navigation and a more content-focused Liquid Glass

    • Is Desk Down?

      Across department - always an error. [Status Mode] - error [Table View and the rest] - working

    • How do I change the wording of the tile of SignForm?

      When my user opens a SignForm url, the title that is presented is always "SignForm signer Information" and a form is displayed asking for the username and email address. This can be confusing to the end user. How can I change the title at least (Or at

    • How to link tickets to a Vendor/Vendor Contact (not Customer) for Accounting Department?

      Hi all, We’re configuring our Accounting department to handle tickets from both customers and vendors (our independent contractors). Right now, ticket association seems to be built around linking a ticket to a Customer / Customer Contact, but for vendor-originated

    • Unify Overlapping Functionalities Across Zoho Products

      Hi Zoho One Team, We would like to raise a concern about the current overlap of core functionalities across various Zoho applications. While Zoho offers a rich suite of tools, many applications include similar or identical features—such as shift management,

    • Automation #7 - Auto-update Email Content to a Ticket

      This is a monthly series where we pick some common use cases that have been either discussed or most asked about in our community and explain how they can be achieved using one of the automation capabilities in Zoho Desk. Email is one of the most commonly

    • Ticket to article and Ticket to template

      Hello! I would like to know if it is possible (and how) to do the following actions: 1. To generate an article from a ticket (reply + original message) 2. Easy convert an answer to an email template

    • Next Page