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Start from strict, WordPress, API, static, or custom policy configurations.
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Build a Content Security Policy header with source directives, reporting, nonce and security options.
CSP Policy Builder is a powerful online Content Security Policy generator for creating safer HTTP response headers without manually assembling every directive. Choose a practical preset, edit source lists, add a reporting endpoint, and generate a copy-ready Content-Security-Policy or Content-Security-Policy-Report-Only header.
The CSP Policy Builder supports common directives including default-src, script-src, style-src, img-src, font-src, connect-src, frame-src, object-src, base-uri, form-action, and frame-ancestors. It also recognizes nonce and SHA-256, SHA-384, or SHA-512 hash sources.
Focused controls, predictable output, and a workflow designed around this exact transformation.
Start from strict, WordPress, API, static, or custom policy configurations.
Use nonce and SHA source expressions instead of broad inline-script permissions.
Identify unsafe-inline, unsafe-eval, wildcard sources, and enforcement risks.
Generate an HTTP header, policy value, and supported meta-tag version.
Practical details about input, output, privacy, limits, and the best way to use this tool.
A CSP Policy Builder creates a Content Security Policy from selected directives and trusted source values, reducing syntax mistakes when preparing an HTTP security header.
Yes. Existing sites should normally deploy Content-Security-Policy-Report-Only first, review violations, fix required sources, and enforce only after testing.
default-src provides a fallback source list for fetch directives that are not explicitly defined. Specific directives such as script-src override it.
No. They weaken important CSP protections. Prefer nonces, cryptographic hashes, external files, and narrowly scoped trusted sources.
Some enforcement directives work in a meta tag, but Report-Only does not. Several directives and reporting features require an HTTP response header.
A server generates an unpredictable nonce for each response, includes it in script-src or style-src, and places the matching nonce attribute on approved inline elements.
frame-ancestors controls which parent pages may embed the document, helping protect against clickjacking. It must be delivered as an HTTP header.
No automated builder can understand every application dependency. Test representative pages, review violation reports, and have security-sensitive policies reviewed.
A CSP Policy Builder creates a Content Security Policy from selected directives and trusted source values, reducing syntax mistakes when preparing an HTTP security header.
Yes. Existing sites should normally deploy Content-Security-Policy-Report-Only first, review violations, fix required sources, and enforce only after testing.
default-src provides a fallback source list for fetch directives that are not explicitly defined. Specific directives such as script-src override it.
No. They weaken important CSP protections. Prefer nonces, cryptographic hashes, external files, and narrowly scoped trusted sources.
Some enforcement directives work in a meta tag, but Report-Only does not. Several directives and reporting features require an HTTP response header.
A server generates an unpredictable nonce for each response, includes it in script-src or style-src, and places the matching nonce attribute on approved inline elements.
frame-ancestors controls which parent pages may embed the document, helping protect against clickjacking. It must be delivered as an HTTP header.
No automated builder can understand every application dependency. Test representative pages, review violation reports, and have security-sensitive policies reviewed.
The CSP Policy Builder combines directive names with validated source expressions and produces a standards-oriented policy string. The generated output includes the complete HTTP header and a separate policy value for server configuration.
Content Security Policy reduces the browser locations from which scripts, styles, images, fonts, frames, and network connections may load. A narrow policy can limit the impact of injected markup, but CSP complements rather than replaces output escaping, sanitization, authentication, and secure coding.
default-src supplies a fallback. script-src and style-src control executable scripts and styles. img-src and font-src cover visual assets. connect-src limits fetch, XHR, EventSource, and WebSocket connections. frame-src controls framed documents, while frame-ancestors controls who may frame your page.
object-src 'none', a narrow base-uri, and a restricted form-action are strong defaults for many applications. Review every source added by plugins, analytics, fonts, payment providers, embedded media, and API endpoints.
A nonce source has the form 'nonce-randomValue'. The value must be unpredictable and regenerated for each HTTP response. A matching nonce attribute authorizes the intended inline script or style.
Hash sources such as 'sha256-...' authorize exact inline content. Any content change requires a new hash. Nonces and hashes are normally safer than enabling 'unsafe-inline'.
Report-Only mode records violations without blocking resources. Exercise the site across login, checkout, account, admin, forms, embedded media, analytics, and third-party integrations. Investigate each violation rather than adding broad wildcards.
After reports stabilize, deploy the enforcement header gradually and continue monitoring. A policy that blocks critical scripts can break navigation, payment, authentication, or accessibility features.
Frequent mistakes include combining 'none' with other sources, allowing all domains with *, copying a static nonce into every response, using 'unsafe-eval' without necessity, and assuming a meta tag supports every directive.
Another mistake is defining only default-src and overlooking application-specific connections, frames, fonts, or form destinations. Use browser developer tools and CSP reports to discover legitimate dependencies.
Continue with HTTP Header Builder, cURL Builder, or OpenAPI Generator.
Review the MDN Content Security Policy guide and the W3C CSP Level 3 specification.