How to Remove Your Domain from the HSTS Preload List

If your domain is on the HSTS preload list and you need it out, the process is simple on paper and annoyingly slow in practice. The hard part is not the form submission. The hard part is understanding what browsers will keep doing after you change your headers, and making sure you do not trap users behind a broken HTTPS setup while preload removal works its way through browser releases. ...

May 14, 2026 · 7 min · headertest.com

HSTS for API Endpoints: Pros, Cons, and Deployment Guide

If you run APIs over HTTPS, HSTS looks like an easy win. Set one header, tell clients to never use HTTP again, and reduce downgrade and cookie leakage risks. That’s the sales pitch. For browser-facing traffic, I’m generally a fan. For API endpoints, the answer is more nuanced. HSTS absolutely helps in some API deployments, does almost nothing in others, and can create operational headaches if you roll it out carelessly. ...

May 9, 2026 · 7 min · headertest.com

HSTS vs Mixed Content: Pros, Cons, and Real Fixes

HSTS and mixed content get lumped together because they both live in the HTTPS world. But they solve different problems, fail in different ways, and trip up different teams. If you’re building or maintaining a site, you need to understand the gap between them: HSTS tells the browser to always use HTTPS for your domain. Mixed content happens when an HTTPS page still loads some resources over HTTP. That distinction matters. I’ve seen teams proudly enable HSTS and assume they’re done, while their pages still pull images, scripts, or CSS over plain HTTP. That’s not “mostly secure.” That’s a site with sharp edges. ...

May 5, 2026 · 7 min · headertest.com

HSTS and Downgrade Attack Prevention

If you serve HTTPS and you’re not using HSTS, you still have a weak first step. That sounds harsh, but it’s true. A site can have a perfectly valid TLS setup and still be vulnerable to downgrade tricks that push users onto plain HTTP before HTTPS ever gets a chance. HSTS fixes that by telling browsers: “for this site, never use HTTP again.” That one rule shuts down a whole class of annoying and very real attacks. ...

May 4, 2026 · 7 min · headertest.com

HSTS for Dart with Shelf: Copy-Paste Reference

HTTP Strict Transport Security is one of those headers you set once, then forget about until you realize your rollout plan was sloppy. If you run a Dart app with Shelf, HSTS is straightforward: send a Strict-Transport-Security response header on HTTPS responses, and don’t break local development while doing it. This guide is the practical version: what to send, when to send it, and copy-paste Shelf middleware you can actually use. ...

April 28, 2026 · 7 min · headertest.com

HSTS for Azure Static Web Apps: Options, Pros and Cons

If you host on Azure Static Web Apps, HSTS looks deceptively simple. You want one header: Strict-Transport-Security: max-age=31536000; includeSubDomains; preload Done, right? Not quite. Azure Static Web Apps is great for shipping frontend apps fast, but once you care about security headers, especially HSTS, you run into a design constraint: you do not get full control over the edge like you would with a custom reverse proxy, Nginx, or a tuned CDN setup. ...

April 27, 2026 · 7 min · headertest.com

HSTS Mistakes on Heroku and How to Fix Them

HSTS on Heroku looks simple right up until you ship it wrong and lock users into a bad HTTPS setup. I’ve seen this happen a few times: someone enables SSL on Heroku, adds a redirect to HTTPS, throws in Strict-Transport-Security, and calls it done. Then a week later they realize staging is broken, a custom domain is misconfigured, or preload was enabled before every subdomain was actually ready. Heroku makes TLS termination easy. That does not mean HSTS is automatic, or safe by default. ...

April 24, 2026 · 7 min · headertest.com

HSTS for Deno Deploy: Pros, Cons, and Practical Setup

HSTS on Deno Deploy is one of those security controls that’s easy to enable and surprisingly easy to get wrong. If you’re serving anything real on Deno Deploy, you should at least make an intentional decision about HTTP Strict Transport Security instead of leaving it as “probably fine.” HSTS tells browsers: only talk to this site over HTTPS for a set period of time. That shuts down a whole class of downgrade and SSL-stripping attacks. ...

April 22, 2026 · 7 min · headertest.com

HSTS for Node.js with Koa: Copy-Paste Reference

HSTS is one of those headers that looks trivial until you ship it wrong. For Koa apps, the mechanics are easy: send Strict-Transport-Security over HTTPS. The hard part is rollout, preload, proxies, subdomains, and not bricking a staging or legacy setup by accident. This guide is the version I wish more teams had on hand: what to send, when to send it, and copy-paste Koa examples that won’t surprise you later. ...

April 20, 2026 · 7 min · headertest.com

HSTS and Localhost: Common Dev Mistakes and Fixes

HSTS is one of those headers that feels boring right up until it wrecks your local workflow. I’ve seen this happen in teams more than once: someone enables Strict-Transport-Security in a staging or shared dev environment, tests with a real-looking hostname, and suddenly half the team can’t load the app over HTTP anymore. Then people start clearing browser data, changing ports, restarting Docker, and blaming the reverse proxy. The real problem is usually simpler: the browser is doing exactly what HSTS told it to do. ...

April 19, 2026 · 7 min · headertest.com