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

    • How emojis shape customer conversations

      World Emoji Day is celebrated on July 17. Did you know that this date was inspired by the 📅 calendar emoji, which shows July 17 on most platforms? What started as a detail in the emoji's design has turned into a global celebration of these tiny emoticons.

    • Custom Button Creation from Layout Editor in Zoho CRM

      Hello All, Buttons in Zoho CRM act as triggers that perform a specific action when clicked. Zoho CRM includes a set of system buttons that help you carry out common actions with a single click. Beyond these, your organization can create custom buttons

    • Displayed sample tracking for multi branch setup.

      We have multiple branches and one of the biggest challenges for us to be able to track if a particular item is in display or not. I am shooting in the dark but I am wondering if there is a solution for the following : Each product used for display is

    • Using IMAP configuration for shared email inboxes

      Our customer service team utilizes shared email boxes to allow multiple people to view and handle incoming customer requests. For example, the customer sends an email to info@xxxx.com and multiple people can view it and handle the request. How can I configure

    • Introducing Bulk Attachment Download from List View

      We're excited to introduce an update to attachment management in Zoho Recruit that lets you download attachments associated with selected records directly from the List View page of any module. How do I download attachments in bulk? You can now select

    • Advanced Group Settings: Customize and manage your email groups in Zoho Mail

      Email groups in your organization often require more than basic configurations to function effectively. With Zoho Mail's Advanced Group Settings, administrators can configure and manage policies, notifications, and more with greater precision. This gives

    • "code":3001 ["Failed to update data."]

      I would like to seek your expertise - I might be wrong on my approach also.. I highly appreciate your advice. 1 problem remains is when a new row was added on the existing one [from another form that trigger upon Successful form submission ], it gets

    • CRM gets location smart with the all new Map View: visualize records, locate records within any radius, and more

      Hello all, We've introduced a new way to work with location data in Zoho CRM: the Map View. Instead of scrolling through endless lists, your records now appear as pins on a map. Built on top of the all-new address field and powered by Mappls (MapMyIndia),

    • Workdrive on Android - Gallery Photo Backups

      Hello, Is there any way of backing up the photos on my android phone directly to a specific folder on Workdrive? Assuming i have the workdrive app installed on the phone in question. Emma

    • Auto sync Photo storage

      Hello I am new to Zoho Workdrive and was wondering if the is a way of automatically syncing photos on my Android phone to my workdrive as want to move away from Google? Thanks

    • List of Mail Merge Templates via Deluge

      Hello, Is it possible to get a list of the mail merge templates I've created in CRM within a custom function? I want to retrieve them and put them in a dropdown list but all I get is a scopes error! Can anyone see where I'm going wrong? Is this even possible?

    • Feature Request Improve parent-child relationship visibility

      Hi team, The Parent-Child ticket feature is great, but I've struggled to see the relationship between tickets when using ticket list views. It would be a great quality of life enhancement for users if child tickets were nested under parent tickets in

    • Displaying only unread tickets in ticket view

      Hello, I was wondering if someone might be able to help me with this one. We use filters to display our ticket list, typically using a saved filter which displays the tickets which are overdue or due today. What I'd really like is another filter that

    • Is there provision to charge the attendees to join the webinar?

      We want to host some webinar of public interest and want to charge them to participate in this. Does this feature in-build in the application? Offcourse, we will be having Razor pay account activated for these purpose.

    • Pricelists

      So we have them in books but I cannot find them in commerce?

    • Desktop app doesn't support notecards created on Android

      Hi, Does anybody have same problem? Some of last notecards created on Android app (v. 6.6) doesn't show in desktop app (v. 3.5.5). I see these note cards but whith they appear with exclamation mark in yellow triangle (see screenshot) and when I try to

    • Don't send customer email when creating a ticket

      Hi Is there an easy way to stop the system sending an email to the customer when we manually create ticket.

    • Connecting a contact with the deal + Emails not showing up under Deals

      Hello. I have two problems. Im not sure if the problem is due to level of my subscription - Im on Proffessional plan. 1. I have a JotForm connected with ZohoCRM which automatically creates a contact and a new deal based on form submission. That is done

    • Accessing GDPR Data Source metadata for workflows and Zoho Analytics

      Hi everyone, We have GDPR compliance enabled in Zoho CRM, which has added the Data Source section within the Data Privacy tab for Leads and Contacts. This section shows useful information such as: Original creation source, for example Zoho Forms Form

    • Tiktok

      When will Tiktok be added to the Zoho Social Platform?

    • Zoho Mail iOS app update: Spam Controls & Sender Verification

      Hello everyone! We are excited to introduce spam control enhancements in the Zoho Mail iOS app update. Let's dive into what's new. Spam Alerts in Mail Preview : Mail preview now shows warning alerts for emails identified as potentially harmful, helping

    • Mise à jour de Zoho Books – France

      Chers clients, Merci pour votre patience et votre soutien continu. Avec les évolutions réglementaires à venir en France nous introduisons de nouvelles fonctionnalités dans Zoho Books pour les clients français. Ces mises à jour ont été conçues pour répondre

    • 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. Latest Update (27th April 2026): With the early

    • Zoho Books API: Bulk update thousands of records using Node.js with OAuth refresh, retries and resume support

      Hello everyone, During Zoho Books implementations, one common challenge is updating a large number of existing records. The current options are usually: Update records manually from the UI using Mass Update (with limited batch size). Update records one

    • SalesIQ's Summer '26 Release: For The Moments That Matter

      Every customer journey is made up of moments. The moment someone discovers your business. The moment they need help. The moment you decide to reach out. The moment a simple chat turns into something more. And the moments that continue long after the conversation

    • CNIL - Suivi de Pixel

      Bonjour à tous, À la suite de la nouvelle recommandation de la CNIL sur les pixels de suivi dans les e-mails, savez-vous si Zoho Campaigns permet : de conditionner le suivi des ouvertures au consentement de chaque contact ; de proposer un lien permettant

    • Customer/Vendor Portal session duration - can it be extended?

      Hi all, We'd like to know how long the login session lasts for the Customer/Vendor Portal in Zoho Books, and whether there's any way to extend it (either through settings or via support/API). Right now this is causing a pretty poor experience for our

    • Accessible & Customizable User Governance in Zoho Projects!

      As teams expand and collaborate with multiple external collaborators across projects, keeping control of user access to project data becomes a challenge. Mismanaged access can cause accidental or unauthorized edits, data leaks and lack of accountability.

    • Bulk deleting Zoho CRM records using Deluge, COQL and CRM API

      Hello everyone, During CRM implementations, data cleanup is a common task, especially after testing, migrations, imports, or integration development. The Zoho CRM UI allows deleting records in batches of 100, which is not practical when dealing with thousands

    • CNIL - Suivi de Pixel

      Bonjour à tous, À la suite de la nouvelle recommandation de la CNIL sur les pixels de suivi dans les e-mails, savez-vous si Zoho Campaigns permet : de conditionner le suivi des ouvertures au consentement de chaque contact ; de proposer un lien permettant

    • How to View Part Inventory and Warehouse Location When Creating a Work Order in Zoho FSM

      Hi everyone, We’re currently setting up Zoho FSM and would like to improve how our team selects parts when creating a Work Order. Right now, when we add a part or item to a Work Order, we can select it from our Zoho Inventory list but we don’t see any

    • Zoho Sprints - Q2 Updates for 2026

      Improve your agile project management experience with the newly released capabilities in Zoho Sprints. This quarter we've shipped a few new features and enhancements that are built around smarter planning and execution tools, tighter integrations, and

    • Problem with currency field in Zoho CRM

      Hi Guys Zoho Books has a feature in currency fields that automatically converts decimal numbers with commas ( , ) to period format ( . ) when pasting them. For example: R$ 2,50 --> R$ 2.50 Is this behavior available in Zoho CRM? I couldn't find any configuration

    • Building extensions #5: Creating custom user interfaces using widgets

      In our last post, we looked at connections and how they help build a seamless integration with an example. In this post, we'll explore creating widgets in Zoho Sprints and their benefits with a real-time example. Widgets What and where? Widgets are custom

    • Images not saved in notes

      Created noteboards and create a note, copy pasted the image, close the note and open again, image is not coming this same problem occurs in note on notebook I have attached the replication steps as video url to analyse it, and also attached the videos

    • How to Change Notecard Color After It Is Created

      I would like to change the color of a Notecard that already exists in my notebook. I can't for the life of me figure out how to do it. I don't see an option or color picker anywhere.

    • Cannot export Zoho Notebook data nor search via MCP (GDPR)

      Hi, I'm using Zoho Notebook for a few years now. Not as my main notetaking app, but for specific usecases I did find it handy. Now I want to export all my data. Preferably all notes in html format with metadata like note title, included images and parent

    • Add a MATRIX field to the forms creation

      Same as Zoho forms, we need a Matrix field in Zoho Creator forms, is very usefull

    • incoming mails not received

      incoming mails not received

    • Integrate QuickBooks with Bigin and streamline your sales and accounting!

      If your business relies on Bigin for customer management and QuickBooks for accounting and invoicing, this new integration is here to make your operations more efficient. By connecting these two platforms, you can now manage your CRM and financial processes

    • Next Page