Setting Cookie No Longer Working After Deploy: The Ultimate Troubleshooting Guide

Deploying your website or application can be an exciting moment, but it can quickly turn into frustration when you realize that your carefully crafted cookie settings are no longer working as expected. Don’t worry, we’ve all been there! In this comprehensive guide, we’ll dive into the common causes and solutions to get your cookies working again in no time.

Understanding Cookies and Their Purpose

Cookies are small text files stored on a user’s device by a web browser. They’re used to store information about the user’s interactions with a website, such as login credentials, preferences, and session data. Cookies are essential for providing a personalized experience and enabling features like authentication and shopping carts.

Cookies in Modern Web Development

In modern web development, cookies are used extensively to track user behavior, authenticate users, and provide a seamless experience across multiple pages. With the rise of single-page applications (SPAs) and server-side rendering (SSR), cookie handling has become even more critical.

Common Issues with Setting Cookies After Deploy

So, why do cookies stop working after deployment? Let’s explore some common issues:

• Domain and Path Issues: Incorrectly set domain and path attributes can prevent cookies from being stored or retrieved correctly.
• HTTPOnly and Secure Flags: Failing to set the HTTPOnly and Secure flags can make cookies vulnerable to attacks and prevent them from being sent over HTTPS.
• Cookie Size and Expiration: Cookies that exceed the maximum size limit or have expired can cause issues with storage and retrieval.
• Browser Restrictions and Same-Origin Policy: Browser restrictions and same-origin policy can prevent cookies from being set or accessed across different domains and subdomains.
• Server-Side Configuration and CORS: Misconfigured server-side settings and CORS policies can block cookie requests and responses.
• Ad Blockers and Tracking Blockers: Overzealous ad blockers and tracking blockers can interfere with cookie storage and retrieval.

Troubleshooting Steps to Fix Cookie Issues

Now that we’ve covered the common issues, let’s go through a step-by-step troubleshooting process to fix your cookie woes:

Step 1: Verify Cookie Settings in Your Code

Review your code to ensure that cookie settings are correct and consistent across your application:

const cookieOptions = {
  domain: 'example.com',
  path: '/',
  expires: new Date(Date.now() + 31536000000), // 1 year
  secure: true,
  httpOnly: true,
  sameSite: 'Strict'
};

res.cookie('myCookie', 'cookieValue', cookieOptions);

Step 2: Check Server-Side Configuration and CORS

Verify that your server-side configuration and CORS policies are correctly set:

app.use(cors({
  origin: ['https://example.com'],
  credentials: true
}));

Step 3: Test Cookies in Different Browsers and Modes

Test your cookies in different browsers and modes (e.g., incognito, private browsing) to identify browser-specific issues:

Browser	Mode	Cookies Set?
Chrome	Normal	Yes
Chrome	Incognito	No
Firefox	Normal	Yes
Firefox	Private Browsing	No

Step 4: Inspect Cookie Headers and Responses

Use developer tools to inspect cookie headers and responses:

GET / HTTP/1.1
Host: example.com
Cookie: myCookie=cookieValue

HTTP/1.1 200 OK
Set-Cookie: myCookie=cookieValue; Domain=example.com; Path=/; Expires=Wed, 21-Jan-2026 01:23:45 GMT; Secure; HttpOnly; SameSite=Strict

Step 5: Verify Cookie Storage and Retention

Check the cookie storage and retention in your browser’s storage section:

Storage:
  Cookies:
    myCookie: cookieValue
  LocalStorage:
    {}
  SessionStorage:
    {}

Step 6: Review Ad Blocker and Tracking Blocker Settings

Review ad blocker and tracking blocker settings to ensure they’re not interfering with cookie storage and retrieval:

Ad Blocker Settings:
  * Blocking cookies: Off
  * Blocking tracking: Off

Tracking Blocker Settings:
  * Blocking cookies: Off
  * Blocking tracking: Off

Conclusion

Setting cookies no longer working after deploy can be a frustrating issue, but by following these troubleshooting steps, you should be able to identify and fix the problem. Remember to verify your cookie settings, check server-side configuration and CORS, test cookies in different browsers and modes, inspect cookie headers and responses, verify cookie storage and retention, and review ad blocker and tracking blocker settings. With persistence and the right tools, you’ll be setting cookies like a pro in no time!

Additional resources:

• MDN Web Docs: Cookies
• OWASP: SecureFlag
• W3C: CORS

Frequently Asked Question

Are you struggling with setting cookies that no longer work after deployment? Don’t worry, you’re not alone! Here are some frequently asked questions and answers to help you troubleshoot the issue.