HTTPS Everywhere for Firefox: Privacy Benefits Explained

HTTPS Everywhere for Firefox vs Built-in HTTPS: Which Is Better?This article compares the HTTPS Everywhere browser extension (originally developed by the Electronic Frontier Foundation and later maintained by the Tor Project) with Firefox’s built-in HTTPS features, so you can decide which offers better protection, compatibility, and usability for your needs.

Quick answer

Built-in HTTPS protections in modern Firefox are generally sufficient for most users, but HTTPS Everywhere can still provide additional value on older sites or in specific scenarios where its rewrite rules upgrade HTTP connections that the browser might not automatically force.

What each does

• HTTPS Everywhere for Firefox
  HTTPS Everywhere is a browser extension that uses a set of rewrite rules to convert many HTTP requests to HTTPS before they leave your browser. It maintains a list of domains where secure versions are known to exist and applies those rules to upgrade connections. The extension can also include specific exceptions or custom rules the user adds.

• Built-in HTTPS in Firefox
  Firefox has several native features that handle HTTPS:

  • HTTPS-Only Mode — forces sites to load over HTTPS and prompts or blocks connections if HTTPS isn’t available.
  • HSTS (HTTP Strict Transport Security) support — honors server-sent HSTS headers and the preload list embedded in the browser.
  • Opportunistic upgrades and heuristics — Firefox may attempt an HTTPS connection before falling back to HTTP in some cases.

Security comparison

• Encryption coverage

  • Built-in: Covers modern, properly configured sites via HTTPS-Only Mode and HSTS/preload. Firefox’s native handling is integrated with site security indicators and certificate validation.
  • HTTPS Everywhere: Can upgrade some legacy sites where HTTPS exists but isn’t advertised by the server, using its ruleset to rewrite requests to HTTPS.

• Protection against downgrade attacks

  • Built-in: HSTS and preload mitigate many downgrade attacks automatically.
  • HTTPS Everywhere: Adds an extra layer for sites not using HSTS; can prevent accidental HTTP loads where HTTPS is available.

• Trust and maintenance

  • Built-in: Maintained by Mozilla with regular security updates and tightly integrated into the browser’s security model.
  • HTTPS Everywhere: Rules must be kept current. The official EFF/Tor-maintained rulesets were reliable, but third-party or outdated rules can cause issues.

Privacy implications

• Data exposure
  Both approaches aim to prevent plaintext HTTP, reducing risk of eavesdropping. Firefox’s native features are privacy-conscious and do not require third-party rule downloads at runtime. HTTPS Everywhere may fetch or update rules, which is typically minimal but worth noting.

• Telemetry/requests
  Firefox’s built-in functionality operates locally without needing a separate ruleset service. HTTPS Everywhere updates its rulesets periodically; this requires network access but not necessarily identifiable data.

Compatibility and reliability

• Broken pages and mixed content

  • Built-in: Firefox handles mixed content and will block insecure subresources by default; HTTPS-Only Mode can cause pages not to load if HTTPS is unavailable.
  • HTTPS Everywhere: May sometimes force HTTPS on domains whose HTTPS implementations are broken or partial, potentially breaking site functionality. It can be disabled per-site.

• Performance
  Upgrading to HTTPS may add TLS negotiation overhead, but both methods result in similar performance. HTTPS Everywhere’s rule processing overhead is minimal.

Use cases and recommendations

• Most users (everyday browsing, banking, shopping):
  Use Firefox’s built-in HTTPS-Only Mode. It’s integrated, well-maintained, and minimizes complexity.

• Users on older sites or niche services with HTTPS available but not advertised:
  Consider installing HTTPS Everywhere (or a maintained fork) and enable it for those specific sites. Disable it on sites that break.

• Advanced users and privacy-focused setups:
  Combine browser native protections with additional tools like browser extensions that enforce security policies, but be cautious about overlapping functionality and rule maintenance.

How to configure

• Enable HTTPS-Only Mode in Firefox:

  1. Open Settings → Privacy & Security.
  2. Scroll to “HTTPS-Only Mode” and choose “Enable HTTPS-Only Mode in all windows.”

• Install HTTPS Everywhere (if desired):

  1. Visit the add-ons page and install HTTPS Everywhere or a maintained equivalent.
  2. Use the extension’s options to update rules and set per-site exceptions.

Pros and cons

Practical example

A site uses HTTPS but doesn’t redirect HTTP to HTTPS and doesn’t send HSTS. Firefox in HTTPS-Only Mode will not automatically upgrade the initial HTTP request unless you explicitly access the HTTPS URL or it tries an opportunistic upgrade. HTTPS Everywhere can apply a rewrite rule to change http://example.com to https://example.com automatically, improving protection in that scenario.

Conclusion

For most users, Firefox’s built-in HTTPS features are the better choice because they’re integrated, actively maintained, and sufficient for modern web security. HTTPS Everywhere remains useful in niche cases where a site supports HTTPS but doesn’t advertise it; however, weigh the risk of breaking pages and the need to keep rulesets updated.