Security Headers

CSP Examples Cookbook: Copy-Paste Security Headers Content Security Policy (CSP) is still one of the highest-impact browser defenses you can deploy in 2026. A good CSP reduces XSS risk, limits third-party script abuse, narrows data exfiltration paths, and makes supply-chain mistakes less catastrophic. The hard part is not the syntax. The hard part is shipping a policy that matches your stack. This cookbook gives you complete, copy-paste-ready CSP examples for common servers, frameworks, hosting platforms, and integrations. Each example is short, practical, and designed to be adapted with minimal changes. ...

Web fonts are one of those things teams barely think about until the site starts flashing invisible text, Lighthouse complains, or CSP suddenly blocks production traffic. I’ve seen this happen a lot: someone tightens Content Security Policy, feels good about shipping a safer header, and then fonts start failing in subtle ways. Not always completely broken. Sometimes they just get slower. And slow fonts are nasty because they hurt rendering, CLS, and perceived quality without looking like an obvious outage. ...

Teams usually treat icons as harmless. They are tiny, static, and easy to ignore in a CSP rollout. Then the first production deploy lands and half the UI loses its glyphs, the marketing tag manager still works, and somebody “fixes” it by adding img-src * data:. I’ve seen this happen more than once. This case study is about a site I’ll call Bytesize Icons: a developer-facing site with a searchable icon catalog, docs pages, a React app shell, analytics, and consent tooling. The goal was simple: lock down CSP without breaking icon rendering. ...

Adobe Fonts is one of those integrations that looks trivial until your CSP starts blocking it in production. You add the embed code, ship a strict policy, and suddenly your typography falls back to system fonts. Or worse, you loosen style-src too much just to get it working and quietly undo a big chunk of your CSP hardening. I’ve had to clean this up more than once. The good news: Adobe Fonts usually needs only a small set of allowances. The bad news: a lot of examples online are either too broad or copy-pasted from unrelated setups. ...