How to fix missing strict transport security on Squarespace
Add the Strict-Transport-Security (HSTS) response header to every HTTPS page so browsers always use an encrypted connection to your store.
Steps for Squarespace
- Squarespace automatically provisions SSL and enforces HTTPS for all sites — HSTS is intended to be managed at the platform level.
- Verify the header is present on your live domain with browser DevTools or securityheaders.com.
- If missing, contact Squarespace Support referencing the Strict-Transport-Security header. There is no in-dashboard toggle for HSTS.
- If your domain routes through Cloudflare, enable HSTS in Cloudflare → SSL/TLS → Edge Certificates → HTTP Strict Transport Security (HSTS).
What is missing strict transport security?
HTTP Strict Transport Security (HSTS) is a small instruction your web server sends inside every page response that tells browsers: "never load this site over plain HTTP — always use HTTPS, no exceptions." Without it, a browser will happily follow any link or redirect that starts with `http://`, even if your server immediately redirects to `https://`. That brief unencrypted moment is enough for an attacker on the same Wi-Fi network to intercept the request. The HSTS header closes that window entirely by making the browser refuse the insecure connection before it even leaves the device.
Security: Customers shopping on public Wi-Fi are vulnerable to SSL-stripping attacks — where a hacker silently downgrades their HTTPS session to plain HTTP and reads login cookies, payment info, or session tokens in the clear. HSTS prevents this. *SEO & Rankings:* Google uses HTTPS as a confirmed ranking signal and may deprioritize pages that can be reached over HTTP; a strong HSTS policy reinforces your site's "always-HTTPS" status. *Compliance & Legal:* PCI-DSS (required for any store that handles card payments) and GDPR both demand that customer data be encrypted in transit — a missing HSTS header is a finding auditors flag. *Conversions:* Browsers display security warnings for mixed-content or downgrade scenarios; even a brief warning causes visitors to abandon their cart.
See the complete Missing strict transport security guide for every platform and the full background.
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