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 #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.

    • Kaizen #210 - Answering your Questions | Event Management System using ZDK CLI

      Hello Everyone, Welcome back to yet another post in the Kaizen Series! As you already may know, for the Kaizen #200 milestone, we asked for your feedback and many of you suggested topics for us to discuss. We have been writing on these topics over the

      • Recent Topics

      • Request for Auto PO - Min–Max based Automated Purchase Feature

        Dear Zoho POS Team, I’m writing to request a feature enhancement that would significantly streamline inventory management for businesses using Zoho POS — particularly supermarkets, FMCG retail, and multi-store operations like ours. Feature Requested:

      • Masters in UK – Experiences, Universities, and Career Outcomes

        This forum discussion is for students who are planning or considering a Masters in UK and want to gain practical insights beyond official university websites. The UK attracts international students due to its globally recognized universities, diverse

      • Export your notes from Notebook!

        Dear users, The long awaited feature is now live. Yes, you can now export your notes from Notebook app in bulk. But the feature has just started with web app alone for now. You can try the export feature as mentioned below: Go to our web app, https://notebook.zoho.com Go to 'Settings' > 'Export' Now, select the format: You can select either ZNote or HTML Once done, you can use the same to import or can have this a local backup of your notes. Note: Export for other platforms are in development and

      • Prepopulating Fields

        Hello, I have a form (Assets) with 2 lookup fields: Client (from Clients) Site (from Client Sites) I modified the code (highlighted in red below), so the Site dropdown shows the list of sites related to the Client. must have Client_Site ( type = picklist

      • Unable to sort as Descending order

        Trying to change the sort order for a lookup field (checkboxes) from Ascending to Descending and keep getting an error in Deluge that the order must be Ascending Did anyone ran into this? Thanks Eyal

      • Export Invoices to XML file

        Namaste! ZOHO suite of Apps is awesome and we as Partner, would like to use and implement the app´s from the Financial suite like ZOHO Invoice, but, in Portugal, we can only use certified Invoice Software and for this reason, we need to develop/customize on top of ZOHO Invoice to create an XML file with specific information and after this, go to the government and certified the software. As soon as we have for example, ZOHO CRM integrated with ZOHO Invoice up and running, our business opportunities

      • Can I change the format of the buttons in the email templates?

        Hi all! We have been working hard trying to brand our email templates, and have some way to go yet. One of the things we can't seem to edit is the green ${Cases.CUSTOMER_PORTAL_BUTTON} button and the font of the View Ticket text. Is there any way of doing

      • issue with deluge script

        i used chat gpt to build this script and I am getting 2 errors which I cannot figure out how to fix: void monthly_sales_order_generation() { try { // ---------------- CONFIG ------------------- analytics_url_1 = "https://analytics.zoho.com/api/<workspaceID>/report/<reportID1>/data";

      • Introducing LinkedIn Apply Connect for Zoho Recruit

        Attract up to 3x more qualified candidates and hire more efficiently with LinkedIn Apply Connect. Let candidates fill-in job applications without any redirections, gain deeper insights with applicant highlights within Zoho Recruit, and keep candidates

      • Recruit paid support?

        Hi all, Could anyone who has paid support package advise if it provides value for money with regards to support response times? Exploring the idea as unfortunately when we have faced issues with Recruit it has been a 7+ day timescale from reporting to

      • Introducing Dedicated Modules for Plans, Addons, and Coupons in Zoho Billing

        We’ve enhanced the way you manage Plans, Addons, and Coupons in Zoho Billing. Previously, all three grouped together under Subscription Items. Now, each one has its own dedicated module, giving you a cleaner and more intuitive experience. This update

      • Ticket Status email

        Good day, This was discussed in the past, but it would be helpful if we could have the system assign a custom response to a status. We have various statuses for tickets, e.g. "closed due to no response", or "Pending Status", it would be helpful for the

      • Customer ticket creation via Microsoft Teams

        Hi all, I'm looking to see if someone could point me in the right direction. I'd love to make it so my customers/ end users can make tickets, see responses and respond within microsoft teams. As Admin and an Agent i've installed the zoho assist app within

      • Holidays

        Hi; For defining Holidays, you need to add logic to handle the year as well as the month & day. We need to be able to enter Holidays for the next year. I need to add a holiday for January 2, 2017, but I can't until January 1st, which is a Sunday and we

      • Can I use a Standalone CRM Function as the Callback URL For Async Export Data API?

        I am creating an export job using this API https://www.zoho.com/analytics/api/v2/bulk-api/export-data-async/create-export/view-id.html There is a "callbackUrl" key in the CONFIG object. I tried copying the URL for a standalone function in CRM which can

      • Future Orders - Due Date

        Hi In my role, I can receive tickets where the work required is requested months in advance. Using a Future Orders option, which I believe was setup under the On Hold status type, hides the Due Date, in all views/ticket etc. Whilst I understand the reasoning

      • Introducing Withdrawal Reasons for Offers

        We’re excited to introduce a new enhancement to the Offer module that brings more clarity and accountability to every withdrawn offer. The Withdrawal Reason update ensures that each withdrawal — manual or automatic — is backed by a clear explanation,

      • Zoho Creator customer portal users

        Hi, I'm in a Zoho One subscription with our company. I'm running a project now that involves creating a Zoho Creater application and using the Zoho Creator Customer Portal.  At most we need 25 customer portal users. In our Zoho One plan we only get 3

      • GPS tracking only or Check out facility

        Dear Team, Zoho CRM is quite robust CRM but till date i was waiting for the feature of having GPS tracking of Sales employees which is a common demand by all customers for thier field sales executives. We cover them by saying that CRM provides Checkin

      • HTML Tags added to Reports with Notes

        Recently Zoho added the ability to markup text within notes. That way, users can change font size, colors, etc. It's a great change. However, since the change, reports that include a column for "Note Content" are printing HTML tags within the report.

      • In App Auto Refresh/Update Features

        Hi,    I am trying to use Zoho Creator for Restaurant management. While using the android apps, I reliased the apps would not auto refresh if there is new entries i.e new kitchen order ticket (KOT) from other users.   The apps does received notification but would not auto refresh, users required to refresh the apps manually in order to see the new KOT in the apps.    I am wondering why this features is not implemented? Or is this feature being considered to be implemented in the future? With the

      • Appraisals on Employee Information Profile

        Is it possible to show completed appraisals on each employee's "Employee Information" page? I would presume at the bottom - similar to the "Related Lists" concept in Zoho CRM. Obviously view access would be limited to employee and appropriate other roles

      • AI Interview Insights: Turn Recorded Interviews into Quick Transcripts & Summaries

        Evaluating interviews shouldn’t require replaying long recordings or taking manual notes. With AI Interview Insights, you can now review complete transcripts and AI-generated summaries of your One-way (Recorded) interviews right inside Zoho Recruit. This

      • Kaizen #220: Actions API - Webhooks APIs - Part 2

        Hello all!! Welcome back to the follow-up Kaizen post of Kaizen #219: Actions API - Webhooks APIs - Part 1. In the previous week, we covered how to configure a basic Webhook and how to include Headers, Body, and URL Parameters using both the POST Webhook

      • Standard Payment Term is not pulled from account to quotation

        Hey Team There seems to be something off. I do have "Net 30" as my default payment term in Zoho Books for my customers. If, from the customer overview or quote section, I create a new Quotation, the payment terms field stays blank and doesn't get the

      • Canva Integration

        Hello! As many marketing departments are streamlining their teams, many have begun utilizing Canva for all design mockups and approvals prior to its integration into Marketing automation software. While Zoho Social has this integration already accomplished,

      • Manage your invoices from Bigin's mobile app (iOS)

        Hello everyone! We're happy to announce that users can now integrate Zoho Books with the latest version of Bigin's iOS app. Zoho Books can be integrated with Bigin only via the web application. Users can view the Zoho Books tab in the detail pages of

      • HubSpot CRM to Zoho Creator Integration

        I'm trying to create an integration between HubSpot CRM and Zoho Creator with HubSpot being the push source (if a contact is created or updated in HubSpot, it pushes the information to Zoho Creator). I have two questions: 1- Is it best to use Zoho Flow

      • Systematic SPF alignment issues with Zoho subdomains

        Analysis Period: August 19 - September 1, 2025 PROBLEM SUMMARY Multiple Zoho services are causing systematic SPF authentication failures in DMARC reports from major email providers (Google, Microsoft, Zoho). While emails are successfully delivered due

      • Accessibility controls and multilingual captcha authorization for Help Center users ​

        Hello everyone, As part of our ongoing effort to improve user experience, we are excited about the accessibility controls and predefined accessibility personas added in the Help Center, similar to what is already available in Zoho Desk. Help Center users

      • Gain control over record sharing with portal users through our new enhancement: criteria-based data exposure

        Dear Customers, We hope you're well! Portals is a self-service avenue through which your clients can access and manage their direct and related data in Zoho CRM. This empowers them to be more independent and enables them to experience a sense of transparency

      • Zoho Sign + Zoho CRM : la solution pour simplifier vos accords de vente

        La conclusion d’un contrat de vente nécessite de nombreuses étapes : préparation de documents, validations successives et collecte des signatures. Les équipes commerciales passent souvent par plusieurs cycles de collaboration et de révision, tout en assurant

      • Zoho Desk Limitations

        Good day, all, I would like to know whether others share my frustration with some of Zoho's limitations. Don't get me wrong, I like Desk (and I also have a subscription for Analytics), I have been with them for close to 10 years, and unfortunately, I

      • Item/service subtotal

        Just discovered & really pleased that we can drag to re-order the line items in Sales orders & Invoices, a very nice feature which doesn't seem to be documented? It would be nice to be able to insert a subtotal as a line item to complete this great feature

      • Converting Sales Order to Purchase Order

        Hi All, Firstly, this code works to convert a sales order(SO) to a purchase order (PO) via a button, however I am running into an issue when I convert the SO where the values from the line items are not pulled across from the SO to the PO. The ones in

      • how to Solve Conflict Invoices in Zoho POS

        Hello Team, I am facing a repeated issue in Zoho POS while saving a sale that contains service-based items. My products are intentionally created as Service (Non-Inventory) items because I do not want to track stock for them. However, every time I try

      • All new Address Field in Zoho CRM: maintain structured and accurate address inputs

        The address field will be available exclusively for IN DC users. We'll keep you updated on the DC-specific rollout soon. It's currently available for all new sign-ups and for existing Zoho CRM orgs which are in the Professional edition. Latest update

      • Copy, Paste, Highlighted text

        when i copy paste text it gets highlighted. Fix this.  WTF is with this black highlight ? Fix copy pasting. Some people pay for using this mail service. 

      • Pricing Strategies: #6 Common Mistakes while Configuring Pricing

        "Why does this month's billing feel messy again?" That was the exact line Priya muttered while staring at the spreadsheet full of edited pricing, one-off discounts and mismatched subscription details. Her business was growing, but the pricing machine

      • Publish to LinkedIn via API

        Hi, Is it possible to publish a job opening to LinkedIn (paid job slots) if creating a job opening via api / deluge function? Or is the user required to manually publish via the job boards process? Many Thanks Adrian

      • Next Page