How to fix hsts disabled on Shopify

Steps for Shopify

1. Shopify automatically enforces HTTPS and sets HSTS for all stores on the shopify.com infrastructure — you cannot and do not need to set it manually in the Shopify admin.
2. If you use a custom domain, go to Admin → Settings → Domains and ensure your domain shows a green 'Connected and redirecting to HTTPS' status; Shopify then manages the HSTS header for you.
3. If your store sits behind a custom reverse proxy or a third-party CDN (e.g., Cloudflare in front of Shopify), set the HSTS header in that proxy layer — see the Cloudflare steps below.
4. Verify the live header at your domain using browser DevTools (F12 → Network → your domain request → Response Headers) and confirm Strict-Transport-Security is present with max-age=31536000.

What is hsts disabled?

HTTP Strict-Transport-Security (HSTS) is a security header your web server sends to browsers. It tells the browser: "Never load this site over plain HTTP — always use HTTPS, no matter what." Once a browser sees this instruction, it enforces HTTPS automatically for the duration you specify (the max-age, measured in seconds). A max-age=0 effectively disables HSTS, meaning the browser forgets the rule immediately and offers no protection. The correct setting is max-age=31536000 (one year) with includeSubDomains so all parts of your site are covered.

Without a valid HSTS header, shoppers who type your domain into a browser or click a plain HTTP link are briefly exposed to a "downgrade attack" — a hacker on the same network (e.g., public Wi-Fi) can intercept that first unencrypted request and silently redirect them to a fake version of your store, stealing passwords, credit card numbers, or session cookies. This is classified under OWASP's A02:2021 Cryptographic Failures, one of the most exploited vulnerability categories in real-world breaches. Beyond security, Google has used HTTPS as a ranking signal since 2014, and browsers display "Not Secure" warnings that destroy shopper trust and conversion rates. Fixing HSTS is a free, low-effort change with immediate security and trust benefits.

See the complete Hsts disabled guide for every platform and the full background.