With all the new data privacy laws, it may often be difficult for a business to stay compliant, especially eCommerce stores that function in multiple jurisdictions. One area of concern is session cookies. What are they and are they GDPR compliant?
Session Cookies & Their Strictly Necessary Nature
Session cookies are stored on a visitor's browser while they're actively navigating the website. They're not persistent since they're deleted as soon as the user closes their browser session, although some session cookies persist until the website is visited again. A common example is a shopping cart cookie storing cart items while a customer shops on an eCommerce website. Session cookies can also temporarily store website data to increase page loading speeds. Under GDPR strictly necessary cookies↗ are cookies exempted from informed consent because they're essential to the website's core functionality. Session cookies fall into this category (with a few exceptions) since they're temporary and only perform functions necessary for the visitor to use the website.
Does This Make Session Cookies Exempt From GDPR Consent?
Because session cookies fall into the scope of strictly necessary cookies as the visitor navigates the website, they are exempt from GDPR consent, allowing websites to use them without needing to ask a user for their consent. However, it's important to check that each session cookie performs a task that's essential to the website's functionality, even if it's temporary. If there's any uncertainty, it's best to block them first until consent is received. You can also include a section on session cookies in your cookie consent policy↗ to have an official document to refer to.
Conclusion
Session cookies are very important in offering a good user experience as well as enabling the website to remember past visitors. Ensuring GDPR compliance↗ isn't so easy, but at least you can rest easy that your session cookies are in the clear.
How Session Cookies Work in Your Shopify or BigCommerce Store
When a customer lands on your eCommerce store, your platform automatically sets session cookies to track their behavior during that visit. Your Shopify store uses session cookies to remember what products they've viewed, items in their cart, and login information. BigCommerce does the same thing. These cookies never leave your server storing identifying personal data — they're just temporary markers that help your store function smoothly.
The key distinction here is scope. A session cookie only exists while the browser tab is open. The moment your customer closes their browser or doesn't visit for a set period (usually 20-30 minutes), the session ends and the cookie deletes itself. This temporary nature is exactly why regulators consider them "strictly necessary" — your store literally cannot process orders, maintain shopping carts, or prevent fraud without them.
On Shopify, you'll see session cookies labeled as things like _shopify_s or _shopify_y. BigCommerce uses similar identifiers. These aren't collecting data for marketing or tracking — they're infrastructure. Your payment processor also relies on session cookies to securely complete transactions. If you blocked all session cookies, your checkout would break entirely, which is why GDPR explicitly allows them without asking permission first.
That said, not every cookie your platform sets is automatically "strictly necessary." Some third-party apps you install might set their own cookies during the session. You need to audit what's actually running on your store and whether each cookie truly serves a core function. A/B testing tools, analytics trackers, and recommendation engines might set session cookies too — and those do require consent.
Session Cookies vs. Persistent Tracking Cookies
This is where many eCommerce brands get confused. Session cookies end when the browser closes. Tracking cookies persist for months or even years, following your visitor across the web. These are very different things legally, and you need to treat them differently.
A persistent cookie might store a customer's language preference or remember they're a loyalty member — genuinely useful for repeat visits. But if that cookie is also feeding data back to Google Analytics, Meta Pixel, or Criteo for retargeting purposes, it's no longer just "necessary." It's now a tracking cookie that requires explicit consent under GDPR.
Your Klaviyo integration is a practical example. Klaviyo sets cookies to track email subscribers and their behavior. Those cookies persist beyond the session. Even though Klaviyo helps you run your business, GDPR requires consent before you can drop those cookies — they're not strictly necessary for your website to function; they're necessary for your marketing to function.
Many eCommerce stores accidentally mix these two types. You might have a session cookie managing the shopping cart (exempt) while simultaneously setting a persistent cookie for abandoned cart recovery (requires consent). Both cookies might fire at the same time, but only one is strictly necessary.
The practical takeaway: audit your store's cookies by category. Session-only cookies for cart, login, and fraud prevention can remain unblocked. Any persistent cookies — even for good business reasons like email marketing or analytics — should be blocked until consent is received. Use your cookie banner to be transparent about this distinction.
Auditing Session Cookies on Your Store
You can't assume your platform's default settings are compliant just because it's Shopify or BigCommerce. You need to actually check what cookies are being set and why.
Start by visiting your store in an incognito browser window and using your browser's developer tools (F12 in Chrome) to inspect the Application or Storage tab. Look for cookies and note which ones expire when you close the browser versus which ones have future expiration dates. Document each one: the name, domain, expiration date, and what it does.
Check your installed apps too. Many Shopify and BigCommerce apps request permission to set cookies, but the request gets buried in your app settings. Review your recent app installations and check their privacy policies for cookie usage.
If you're running Google Analytics, Meta Pixel, or Hotjar, those tools set persistent cookies by default. They're not session cookies — they're tracking cookies that require a consent banner and user opt-in.
For your payment processor integration (Stripe, PayPal, Shopify Payments), the cookies they set are legitimately necessary for transactions. Document these separately in your cookie policy so you can explain to customers why they're set without consent.
Create a simple spreadsheet listing each cookie, its type (session vs. persistent), its purpose, and whether it requires consent. This audit takes an hour but gives you a defensible record if regulators ask questions.
What Happens If You Block Session Cookies by Default
Some brands try to be overly cautious and block all cookies until consent is given. This almost always breaks your store's functionality and tanks your conversion rate.
If you block session cookies, customers won't be able to add items to their cart properly. Login sessions become unstable. Payment processing may fail because your store can't maintain state during checkout. You'll get cart abandonment spikes and customer support complaints within hours of implementing this policy.
GDPR doesn't require this. The regulation exempts truly necessary session cookies. Regulators know that eCommerce stores need basic functionality cookies to operate. What they care about is transparency and stopping non-necessary tracking.
The right approach: let session cookies fire freely from day one, then use your cookie banner to transparently explain what's happening. Your banner should disclose which cookies are set without consent (session/necessary cookies) and which ones require opt-in (analytics, advertising, etc.). Customers appreciate honesty, and you maintain a functioning store.
If your current setup doesn't clearly separate necessary from non-necessary cookies, or if you're unsure whether each cookie has a legitimate functional purpose, now's the time to install a proper consent management layer that handles this distinction automatically.