HTTP vs HTTPS explained simply

HTTP vs HTTPS explained simply

This checklist guide explains the practical differences between HTTP and HTTPS and helps you decide what to check when securing a website or service for users and infrastructure teams alike.

HTTP, or HyperText Transfer Protocol, sends requests and responses in plain text and is suitable only for non-sensitive, public content where confidentiality and integrity are not required. HTTPS adds an encryption layer using TLS, which provides confidentiality so data cannot be read in transit, integrity so content cannot be altered without detection, and server authentication so clients can verify they are talking to the intended server. HTTPS typically uses port 443 whereas HTTP uses port 80, and HTTPS requires a valid certificate issued by a trusted certificate authority or a trusted internal signing process.

Use the checklist below when assessing or migrating to HTTPS for an application or site. Each item is practical and focused on infrastructure and operational behaviour.

• Obtain a valid TLS certificate from a trusted issuer or configure an internal PKI and ensure the certificate chain is complete and not expired.
• Deploy the certificate to your web servers or load balancers and confirm correct binding to the service IP and hostname.
• Configure secure TLS versions and cipher suites, preferring TLS 1.2 and TLS 1.3 and disabling obsolete protocols and weak ciphers.
• Set up HTTP to HTTPS redirection at the appropriate layer, using permanent redirects where appropriate and avoiding redirect loops.
• Enable HSTS carefully and consider preload only after thorough testing, remembering that HSTS instructs browsers to use HTTPS automatically for a domain.
• Fix mixed content by ensuring all embedded assets are loaded over HTTPS and update resource origins in templates and CDN configurations.
• Update external integrations, API endpoints and webhooks to use HTTPS and verify mutual TLS where services require stronger authentication.
• Review caching and proxy rules to forward TLS traffic or terminate it at the correct location and ensure cached responses remain valid and secure.
• Test certificate renewal automation and monitoring to avoid unexpected expiries, and plan for key rotations and revocation handling.
• Document the change, update documentation and configuration management repositories, and communicate the migration to stakeholders and ops teams.

After implementing the checklist items, validate the deployment using several simple checks and some deeper inspection. Open the site in a modern browser and confirm the secure padlock and certificate details, use command-line tools to inspect the TLS handshake and certificate chain, and run a configuration scanner or linting tool to detect weak ciphers and protocol fallbacks. Verify that redirects work correctly for both root domains and common subpaths, confirm that mixed content warnings are absent in developer tools, and check that static assets served via a CDN are accessible over HTTPS and have correct cache headers.

Be aware of common pitfalls when switching from HTTP to HTTPS and plan mitigations. Mixed content is a frequent issue that causes blocking of resources and degraded page behaviour, so allocate time to update templates, scripts and third-party references. Redirects can cause SEO or usability issues if not canonicalised correctly, so use 301 redirects and update canonical tags. Certificate misconfiguration or forgotten renewal can cause immediate service disruptions, so automate certificate provisioning and set up alerting for expiry dates. Content-security-policy and cookie flags such as Secure and SameSite may need adjustment once pages are served over HTTPS. For more builds and experiments, visit my main RC projects page.

Use this checklist as a working tool to secure traffic and reduce operational risk, and consult your organisation’s infrastructure documentation for policies on certificate management and TLS configurations. If you want to browse other Infrastructure guides on Build & Automate for related operational checklists and templates, you can see related posts.