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 #197: Frequently Asked Questions on GraphQL APIs

        🎊 Nearing 200th Kaizen Post – We want to hear from you! 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 #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.

      • Celebrating 200 posts of Kaizen! Share your ideas for the milestone post

        Hello Developers, We launched the Kaizen series in 2019 to share helpful content to support your Zoho CRM development journey. Staying true to its spirit—Kaizen Series: Continuous Improvement for Developer Experience—we've shared everything from FAQs

      • Kaizen #193: Creating different fields in Zoho CRM through API

        🎊 Nearing 200th Kaizen Post – We want to hear from you! 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.

      • Client Script | Update - Introducing Commands in Client Script!

        Have you ever wished you could trigger Client Script from contexts other than just the supported pages and events? Have you ever wanted to leverage the advantage of Client Script at your finger tip? Discover the power of Client Script - Commands! Commands

        • Recent Topics

        • How do I move Notes around within a Group?

          It says here: " You can now sort notes by title (alphabetically), or by date modified and date created. You can even organize your notes by dragging and dropping them into a particular order. To sort your notes, simply go to Settings and tap “Sort By.” Please note: all sort settings will be saved and synced across devices, except for custom sorting. Custom sorting will be device specific."However, I am unable to 'custom sort' in either Notebook for Mac or on the Web. In addition, I can't find the

        • Generate a link for Zoho Sign we can copy and use in a separate email

          Please consider adding functionality that would all a user to copy a reminder link so that we can include it in a personalized email instead of sending a Zoho reminder. Or, allow us to customize the reminder email. Use Case: We have clients we need to

        • Zoho Sign: need to leave document pending for up to a year, or maybe there's a better way?

          I have zoho one, maybe there's a better way to do this with another service than sending a zoho sign template from zoho crm. At the end of the day this requirement is due to regulations, no matter how dumb it may seem. I'm just looking for a way of getting

        • Separate Items & Services

          Hi, please separate items and services into different categories. Thank you

        • What's New in Zoho Inventory | Q2 2025

          Hello Customers, The second quarter have been exciting months for Zoho Inventory! We’ve introduced impactful new features and enhancements to help you manage inventory operations with even greater precision and control. While we have many more exciting

        • Mastering Zia Match Scores | Let's Talk Recruit

          Feeling overwhelmed by hundreds of resumes for every job? You’re not alone! Welcome back to Let’s Talk Recruit, where we break down Zoho Recruit’s features and hiring best practices into simple, actionable insights for recruiters. Imagine having an assistant

        • We are unable to process your request now. Please try again after sometime or contact support@zohoaccounts.com

          I cannot sign up and return the error of we are unable to process your request now. Please try again after sometime or contact support@zohoaccounts.com

        • Multi-currency - What's cooking ?

          Hi,       We have been doing this feature for sometime and we would like to give you some glimpses of it.  Working with Multi Currency :        Multicurrency support gives you the ability to handle business transactions in multiple currencies. You can define a base currency for your organization and add more currencies with exchange rates based on the base currency.  Setup :        From the setup page, you can manage all the currencies supported by your organization.       Currencies page        

        • Integrating Chatbot with Zoho Creator Application

          Is it possible to integrate a chatbot with a Zoho Creator application?

        • How to reduce programmatically the image uploaded by user?

          I need a function that will automatically reduce the pixel dimension to 800 x 600 pixels / 180 resolution or (approx. 1.37MB) of image uploaded by user from digital camera, for example, 2271 x 1704 pixels /180 resolution or approx. 11.1MB. After the user selected the image, the function will able to detect if pixels is above 800x600, process the photo (crop/ reduce) and resume upload. Need help...  

        • Dark mode for Zoho Creator / Zoho CRM Code editor

          Hi Team, Is there any plans for Dark mode in Zoho creator / Zoho Crm code editor and development pages in pipeline?

        • Is there a way to make a button scroll down?

          Looking to have a button on a landing page scroll down to another section on the page. Any recomendations outside of coding?

        • Collective-booking event not added to all staff calendars

          We assign two staff to certain events. When the client books this event, it adds it to one staff calendar (the 'organiser') but not the other. How can I ensure all staff assigned to a collective booking get the event in their calendar? (A side note: it

        • Zoho Commerce - Mobile Application

          Does Zoho Commerce have a mobile application for customers to place an order?

        • Commerce Order as Invoice instead of Sales Order?

          I need a purchase made on my Commerce Site to result in an Invoice for services instead of a Sales Order that will be pushed to Books. My customers don't pay until I after I add some details to their transaction. Can I change the settings to make this

        • Quotes in Commerce?

          In Zoho Ecommerce, I need to be able to generate quotes, negotiate with customers, and then generate invoices. Currently, I plan to integrate Zoho CRM to generate quotes. After negotiation and confirmation, I will push the details to Zoho Ecommerce to

        • Register user through Phone Number by Generating OTP

          In zoho commerce , I am developing website on online food store Inilialy the user get verification code to their email for registering there account for login. But I need to login using phone number by generating OTP automatically rather than verification

        • ZOHO Android Client

          Hi, I installed the Android app, but it had an issue, so I reinstalled it. I was able to add multiple accounts, but now when I add the next account, it just duplicates the one I already have and will not even allow me to enter the info for another account.

        • I'd like to suggest a feature enhancement for SalesIQ that would greatly improve the user experience across different channels.

          Hello Zoho Team, Current Limitation: When I enable the pre-chat form under Brands > Flow Controls to collect the visitor’s name and email, it gets applied globally across all channels, including WhatsApp, Messenger, and Instagram. This doesn't quite align

        • Enhance Barcode/QR Code scanner with bulk scanning or continuously scanning

          Dear Zoho Creator, As we all know, after each scan, the scanning frame closes. Imagine having 100 items; we would need to tap 100 times and wait roughly 1 second each time for the scanning frame to reopen on mobile web. It's not just about wasting time;

        • Non-depreciating fixed asset

          Hi! There are non-depreciable fixed assets (e.g. land). It would be very useful to be able to create a new type of fixed asset (within the fixed assets module) with a ‘No depreciation’ depreciation method. There is always the option of recording land

        • Managing Rental Sales in Zoho Inventory

          I am aware that Zoho Inventory is not yet set up to handle rental sales and invoicing. Is anyone using it for rentals anyway? I'd like to hear about how others have found work arounds to manage inventory of rental equipment, rental payments, etc. Th

        • Megamenu

          Finally! Megamenu's are now available in Zoho-Sites, after waiting for it and requesting it for years! BUT ... why am I asked to upgrade in order to use a megamenu? First: Zoho promised to always provide premium versions and options for all included Zoho-applications

        • Cannot access KB within Help Center

          Im working with my boss to customize our knowledge base, but for some reason I can see the KB tab, and see the KB categories, but I cannot access the articles within the KB. We have been troubleshooting for weeks, and we have all permissions set up, customers

        • Zoho Flow to Creator 3001 Respoonse

          I have updated my Flows with the new V2 connection to Zoho Creator, but now some Flows do not work. They take in data from a Webhook and are supposed to create a record in Creator, however creator returns a 3001 message along with a failure, but I cannot

        • File Upload to Work Drive While Adding Records in Zoho Creator Application

          Hi I am trying to set a file attachment field in zoho creator form, to enable the user to upload a scanned document from their local pc. The file should be uploaded to zoho workdrive and not to the default zoho creator storage. The file link should be

        • Why not possible to generate?

          Using this https://desk.zoho.com/DeskAPIDocument#TicketCount#TicketCount_Getticketcountbyfield on my ZML script url :"https://desk.zoho.com/api/v1/ticketsCountByFieldValues?departmentId=XXXXXXXXXXX&accountId!=XXXXXXXXX&customField1=cf_country_1:XXXXXX&field=overDue"

        • email

          Hi My crm email is not working, can you check, I have zoho one account.

        • Need option to see Mass Emails & Cadences in Gmail Outbox OR a dedicated Zoho Outbox

          Hi everyone, Right now, when we send 1:1 emails from gmail (with gmail API connected to Zoho CRM), those emails appear both in gmail's sent folder and in Zoho CRM. That works well. But when we send Mass Emails or Cadence emails form Zoho CRM, they are

        • I can't found API for Sales Receipts

          Hello May you please help me to find an API document for Sales Receipts to get data and retrive a custom fields like Invoice and credit notes Regards

        • Kaizen #205 - Answering Your Questions | Managing Picklists and Enabling History Tracking via Zoho CRM APIs

          Hello everyone! Welcome back to another post in our Kaizen series. In this post, we will look at how you can manage picklist fields in Zoho CRM using APIs. This topic was raised as feedback to Kaizen #200, so we are taking it up here with more details.

        • Multiple Vendor SKUs

          One of the big concerns we have with ZOHO Inventory is lack of Vendor Skus like many other inventory software packages offer. Being able to have multiple vendor skus for the same product would be HUGE! It would populate the appropriate vendor Sku for

        • Internally created tickets

          Hi there When tickets are created internally on-behalf of customers - there is nothing to show that the ticket was created by an internal agent. This means, that it's easy for our agents to confuse tickets which were created by internal team members and

        • Automatically change website passwords

          Hi everyone, We just switched to a Professional package to also use the "Automatically change website passwords" function. But I cannot find anything about it, how to use it, anywhere. Does anyone know how I can use this function? Best, Caspar

        • Change Invoice Prices for an Effective Date

          Hi, It would be a really good feature to be able to change the prices on invoices/recurring invoices from an effective date in the event of price increases. For instance, I am in the process of increasing prices that will be effective from a specific

        • "Other Current Asset" accounts as "Paid Through" accounts in Expense

          It would be incredibly useful to be able to assign accounts of type Other Current Asset as Paid Through accounts in Expense. Currently, Other Current Liability are permitted as Paid Through Accounts. This makes sense, as Credit Cards are current liabilities.

        • Multi column open text questions that allows respondents to add rows for additional information

          I need to create a question that has 2 columns with open text, but I also need to allow respondents to click a "+" button, or something similar, so that they can add additional information if they choose to. I've tried using the Multiple Textboxes type

        • Bot Filtering & Apple Mail Privacy Protection Compliance in Zoho Campaigns

          Dear Campaigns Users, The wait is over! We’re excited to announce that the enhanced bot filtering feature is now live in Zoho Campaigns. This update brings greater accuracy to your email campaign reports by distinguishing real user engagement from automated

        • Découvrons les détails qui simplifient vos journées de travail avec Trident

          Nous nous installons dans des routines efficaces et rodées avec le temps. Chaque matin, nous ouvrons nos e-mails, passons aux messages, consultons notre agenda, puis attaquons nos tâches. Ce processus nous semble maîtrisé, mais est-il réellement optimisé

        • Issue with Purchase Rate Showing as “0” After Importing Items List

          Dear Zoho Books Support Team, Good day. I’m reaching out regarding an issue I’m facing while importing my items list into Zoho Books. Despite mapping all fields correctly and including the purchase price for each product in my Excel file, the Purchase

        • Next Page