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:


      Zoho Campaigns Resources


        • Desk Community Learning Series


        • Digest


        • Functions


        • Meetups


        • Kbase


        • Resources


        • Glossary


        • Desk Marketplace


        • MVP Corner


        • Word of the Day


        • Ask the Experts


          • 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

          Zoho CRM Plus Resources

            Zoho Books Resources


              Zoho Subscriptions Resources

                Zoho Projects Resources


                  Zoho Sprints Resources


                    Zoho Orchestly Resources


                      Zoho Creator Resources


                        Zoho WorkDrive Resources



                          Zoho CRM Resources

                          • CRM Community Learning Series

                            CRM Community Learning Series


                          • Tips

                            Tips

                          • Functions

                            Functions

                          • Meetups

                            Meetups

                          • Kbase

                            Kbase

                          • Resources

                            Resources

                          • Digest

                            Digest

                          • CRM Marketplace

                            CRM Marketplace

                          • MVP Corner

                            MVP Corner




                            Zoho Writer Writer

                            Get Started. Write Away!

                            Writer is a powerful online word processor, designed for collaborative work.

                              Zoho CRM コンテンツ



                                ご検討中の方

                                  • Recent Topics

                                  • Accessing shared mailboxes through Trident (Windows)

                                    Hi, I have a created a couple of shared mailboxes. The mailboxes are showing up on the browser based Zoho workplace, but I cannot seem to figure out how to access my shared inboxes through Trident (Windows). Am I missing something or is this feature not

                                  • Feature Request: Ability to set Default Custom Filters and apply them via URL/Deluge

                                    I've discovered a significant gap in how Zoho Creator handles Custom Filters for reports, and I'm hoping the Zoho team can address this in a future update. This limitation has been raised before and continues to be requested, but remains unresolved. The

                                  • Closing the Loop: Why Lookup Asymmetry is Harming Data Integrity in Creator

                                    TL;DR: Lookup fields allow users to add new related records inline via the "+" icon, but there's no equivalent ability to edit an existing related record without navigating away and losing form context. Adding a native "Edit" icon—with automatic User

                                  • filtering lookup field options based on information in another module.

                                    In our CRM system. We have the standard Accounts and Deals modules. We would like to introduce the ability to classify Accounts by Sector. Our desired functionality is to have a global list of all sectors that an Account can select, with the ability to

                                  • Service op locatie organiseren met Zoho FSM: waar lopen organisaties tegenaan?

                                    Bij organisaties met service teams op locatie merken we vaak dat de complexiteit niet zozeer in de planning zelf zit, maar in wat er rond die planning gebeurt. Denk aan opvolging na interventies, consistente servicerapporten, en het bijhouden van installaties

                                  • Introducing Assemblies and Kits in Zoho Inventory

                                    Hello customers, We’re excited to share a major revamp to Zoho Inventory that brings both clarity and flexibility to your inventory management experience! Presenting Assemblies and Kits We’re thrilled to introduce Assemblies and Kits, which replaces the

                                  • Does the ability exist to make tax on the customer profile mandatory?

                                    I am reaching out to inquire about the possibility of making the "Customer Tax" field mandatory when creating a new customer in Zoho. We want to ensure that all customers have their tax information recorded to maintain compliance with our internal processes.

                                  • email association with CRM

                                    Why is it 2024 (almost 2025) and Zoho has not figured out how to integrate email with CRM? It is so inconsistent at associating emails within CRM. I am an attorney. I have clients and work with other attorneys. Attorney John Doe is associated with multiple

                                  • Credit Note for Shipped and Fatoora pushed invoices

                                    We have shipped a Sales Order and created an Invoice. The Invoice is also pushed to Fatoora Now we need to create a credit note for the invoice When we try it, it says we need to create a Sales Return in the Zoho Books, we have already created a Sales

                                  • FSM - Timesheet entires for Internal Work

                                    Hi FSM Team, Several of my clients have asked how they can manage internal timesheets within Zoho FSM. Since their technicians already spend most of their day working in FSM, it would be ideal if they could log all working hours directly in the FSM app.

                                  • Add a way of clearing fields values in Flow actions

                                    It would be great if there was an option to set a field as Null when creating flows. I had an instance today where I just wanted to clear a long integer field in the CRM based on an action in Projects but I had to write a custom function. It would be

                                  • Role Management

                                    I am creating an analytics dashboard for a company that will be utilized by its various departments such as Finance, Marketing, and HR. My goal is to design the dashboard with separate tabs for each department. Additionally, I plan to implement role-based

                                  • Highlight a candidate who is "off limits"

                                    Hello: Is there a way to highlight a candidate who is "off limits"?  I would like to have the ability to make certain candidate and / or Client records highlighted in RED or something like that.   This would be used for example when we may have placed a candidate somewhere and we want everyone in our company to quickly and easily see that they are off limits.  The same would apply when we want to put a client or former client off limits so no one recruits out of there. How can this be done? Cheers,

                                  • Announcing new features in Trident for Windows (v.1.37.5.0)

                                    Hello Community! Trident for Windows just received a major update, with a range of capabilities that strengthen email security and enhance communication. This update focuses on making your mailbox safer and your overall email experience more reliable.

                                  • Early Payment Discount customize Text

                                    Hi, I’m currently using Zoho Books and am trying to customize the standard “Early Payment Discount” message that appears in the PDF invoice template. I’ve reviewed the documentation here: https://www.zoho.com/books/help/invoice/early-payment-discount.html

                                  • Deprecation of SMS-based multi-factor authentication (MFA) mode

                                    Overview of SMS-based OTP MFA mode The SMS-based OTP MFA method involves the delivery of a one-time password to a user's mobile phone via SMS. The user receives the OTP on their mobile phone and enters it to sign into their account. SMS-based OTPs offer

                                  • DKIM Now Mandatory - Changes to Zoho Forms Email Policies

                                    Hello Zoho Forms Users, This post is to inform you about an important update regarding the authentication of all email domains in your Zoho Forms account. This year, we are doubling down on our commitment to deliver a secure, seamless, and empowering

                                  • Call description in notes

                                    When completing a call, we type in the result of the call in the description. However, that does not show up under the notes history on the contact. We want to be able to see all the calls that have taken place for a contact wihtout having to go into

                                  • Email Address for Contact not Populating

                                    When I click "Send Mail" from a Contact's page, their email address does not auto populate the "To" field. How do I make this happen?

                                  • New in CRM: Dynamic filters for lookup fields

                                    Last modified on Oct 28, 2024: This feature was initially available only through Early Access upon request. It is now available to all users across all data centers, except for the IN DC. Users in the IN DC can temporarily request access using this form

                                  • Why hybrid project management might be the best fit for you?

                                    Project management techniques are designed to equip teams with proven methods for easy and efficient project execution. While management teams may have apprehensions about adopting the hybrid method of project management, we’ve compiled the top reasons

                                  • Allow all Company Users to view all projects, but only owner/admins can change projects

                                    I was wondering if there was a permission setting I could adjust to allow all our company users to see all projects created. Then, only the project owners and admins with the change permission. Thanks

                                  • Fail to send Email by deluge

                                    Hi， today I gonna update some email include details in deluge, while this msg pops up and restrict me to save but my rules has run for one year. can you tell me how to use one of our admin account or super admin account to send the email? I tried to update

                                  • Seeking help to be able to search on all custom functions that are defined

                                    Hello I have a lot of custom functions defined (around 200) and i would like to search some specific strings in the content of those. Is there a way to accomplish that? If not, is there a way to download all existing custom functions in some files locally

                                  • Totals for Sales Tax Report

                                    On the sales tax report, the column totals aren't shown for any column other than Total Tax. I can't think of a good reason that they shouldn't be included for the other columns, as well. It would help me with my returns, for sure. It seems ludicrous

                                  • Add Bulk Section / Grid Layout Duplicate Feature in Zoho Forms Builder

                                    Currently in Zoho Forms, users can only duplicate individual fields. There is no option to duplicate an entire section or two-column/grid layout with all internal fields. This becomes inefficient when building structured forms such as Family Details,

                                  • Leistungsdatum in Rechnungen (Zoho Books)

                                    Hallo, ist es irgendwie möglich den Leistungszeitraum in der Rechnung aufzuführen? Beste Grüße Aleks

                                  • Zoho Trident Windows - Streams Not Visible

                                    Namaste We’re having an issue with Streams not being visible in Trident (Windows), which is important for us as we share many emails internally. It appears that the feature to show Streams above the Inbox folder, as seen in the default mailbox view, is

                                  • Sales IQ Chat Widget is Only Displaying Last Name

                                    Can anyone suggest why the widget is only displaying "last name"?! We have the latest version of the wordpress plugin installed. Thanks Thanks!

                                  • Shopify - Item sync from Zoho Inventory

                                    Hi team, We’ve connected Shopify with Zoho Inventory. We want that when an item is created in Zoho Inventory, it must create a product in Shopify. But currently, new items created in Zoho Inventory are not getting created in Shopify even after clicking

                                  • Bulk upload image option in Zoho Commerce

                                    I dont know if I am not looking into it properly but is there no option to bulk upload images along with the products? Like after you upload the products, I will have to upload images one by one again? Can someone help me out here? And what should I enter

                                  • Is it possible to setup bin locations WITHOUT mandating batch tracking?

                                    Hi fellow zoho users, I'm wondering if anyone else has a similar issue to me? I only have some products batch tracked (items with shelf life expiry dates) but I am trying to setup bin locations for my entire inventory so we can do stock counting easier.

                                  • Kill zoho meeting

                                    Saying the quiet part out loud. Can zoho please just give up on the idea that they can make a meeting platform and just make our workplace licenses cheaper when you remove it so people can switch to zoom or teams. Tired of the excuses, you guys cant make

                                  • Utilisation de Zoho en conformité avec l’article 286 du Code général des impôts (CGI)

                                    Cher(e) client(e), Conformément à l’article 286 du Code général des impôts (CGI) impose aux entreprises assujetties à la TVA d’utiliser des systèmes de caisse ou de gestion commerciale certifiés lorsqu’elles enregistrent des ventes à des particuliers.

                                  • Unable to Create Task as a Support Administrator

                                    Hello! I want to ask for help regarding creating tasks within the tickets. I am by default the Support Admin. I should be able to create tasks or activities right? But there's a prompt that I need to contact the Administrator. See photos for reference.

                                  • Introducing Forms in Zoho Sheet

                                    We hereby bring you the power of ​forms in Zoho Sheet. ​Now, build and create your own customized forms using Zoho Sheet. Be it compiling a questionnaire or rolling out a survey, Zoho Sheet can do it all for you. Forms is an excellent feature that helps you collect information in the simplest of ways and having it in Zoho Sheet takes it a notch higher. Build Simple yet Powerful forms Building forms using Zoho Sheet is fairly simple. The exclusive 'Form' tab lets you create one quickly. Whether you

                                  • Layout one survey question in a time & redirect next Page based on previous response

                                    I have doubt while, I am scripting survey on the Zoho where I redirecting to next page based on my previous response but didn’t get success on this. Please help me on this and tell me how I layout one survey questions in a time when I submit response

                                  • Zoho Bookings form pre-filled with Zoho Forms in

                                    Hi, I've got a contact page on my website and I'd like to have the option to book an appointment (redirected to zoho bookings page) after an option is submitted on the contact form. how would I go about doing this? thanks

                                  • Support “Other” Option with Free Text in Dropdown Fields

                                    Hello Zoho Bookings Team, Greetings, We would like to request an enhancement to the registration form fields in Zoho Bookings, specifically for dropdown fields. Current Limitation: At the moment, dropdown fields do not support an “Other” option that allows

                                  • Detailed Balance Sheet for tax preparer

                                    I'm using the free edition of Zoho Books. My tax preparer is asking for "detailed" Profit & Loss and Balance Sheet reports which include all the activity and transactions within the various categories. The default reports do not include these details.

                                  • Next Page