Content Security Policy Builder
Build, validate, and export secure Content-Security-Policy (CSP) headers in seconds. Select directive presets, add custom domains, inspect security recommendations using our live auditor, and download your policy file instantly. 100% local and safe.
Enable directives and check desired source presets. Use spaces to separate custom hosts and domains.
Global Security Controls
Upgrades HTTP requests to HTTPS
Prevents loading insecure assets
Fetch Directives
Serves as a fallback for the other fetch directives when they are not explicitly defined.
Specifies valid sources for JavaScript scripts and execution.
Specifies valid sources for stylesheets and CSS styles.
Specifies valid sources for images, favicons, and graphics.
Restricts the URLs which can be loaded using script interfaces (fetch, XMLHttpRequest, WebSocket, EventSource).
Specifies valid sources for web fonts loaded using @font-face.
Specifies valid sources for plugins, such as <object>, <embed>, or <applet>. Recommended to set to 'none'.
Specifies valid sources for loading media (audio and video elements).
Specifies valid sources for nested frame contexts (<iframe> and <frame>).
Specifies valid sources for web workers and nested frame contexts (deprecated in favor of frame-src and worker-src).
Restricts the URLs which may be loaded as a Worker, SharedWorker, or ServiceWorker.
Specifies valid sources for application manifest files.
Document & Navigation
Restricts the URLs which can be used in a document's <base> element.
Restricts the URLs which can be used as the target of form submissions.
Specifies valid parents that may embed a page using <iframe>, <frame>, <object>, or <embed>.
Reporting & Sandbox
Enables a sandbox for the requested resource similar to the <iframe> sandbox attribute.
Instructs the browser to POST reports of policy violations to this URI (deprecated in favor of report-to).
Defines a reporting group configuration name defined in the Report-To HTTP response header.
Live Security Auditor
Client-SideConsider enabling the 'upgrade-insecure-requests' policy. It instructs browsers to automatically upgrade insecure HTTP source links to HTTPS.
Why Use Our Content Security Policy Builder?
Visual Policy Builder
Build policies visually using checkboxes and quick-presets. Choose from multiple options without having to memorize complex directive formats or semicolon rules.
100% Client-Side Privacy
Your policy values, domain configurations, and endpoint names remain inside your browser. No settings are ever uploaded or transmitted to any external servers.
Real-Time Security Auditor
Instantly audits your policy for common misconfigurations as you build. Highlights active security issues like dangerous inline script execution flags in real-time.
Full Directive Coverage
Supports all CSP Level 1, 2, and 3 specs including fetch fallbacks, sandbox tokens, document navigation control, and reporting endpoint headers.
Common Content Security Policy Builder Workflows
Hardening Production Websites
Prevent cross-site scripting (XSS) and data injection attacks by generating a strict default-src policy that restricts assets to trusted sources only.
Meeting Compliance Audits
Easily build SOC2, ISO 27001, or PCI-DSS compliant policies. Demonstrates proper mitigation of unauthorized resource inclusion and framing vulnerabilities.
Hardening Single Page Apps
Generate lightweight, clean policies for React, Vue, and Angular apps. Restricts API connections to specified backends and secures external font dependencies.
Nonce/Hash Verification
Prepare your script policies to support secure cryptographic nonces and hashes, allowing required inline scripts while blocking dynamic unauthorized injections.
Configuring Reporting Endpoints
Incorporate report-uri and report-to directives to collect security violation reports automatically, helping log policy conflicts without breaking active features.
HTTP to HTTPS Migration
Implement upgrade-insecure-requests and block-all-mixed-content directives to ensure all page elements load securely over HTTPS during server upgrades.
Understanding Content Security Policy (CSP)
What Is a Content Security Policy?
A Content Security Policy (CSP) is an HTTP response header that lets website administrators restrict the resources (such as JavaScript, CSS, images, and fonts) that the browser is allowed to load for a given page. It is a critical layer of defense against Cross-Site Scripting (XSS), clickjacking, and other code injection attacks.
How CSP Directives Work
A policy consists of one or more directives separated by semicolons. Each directive restricts resource loads for a specific resource type. For example, script-src specifies trusted sources for JavaScript scripts, and style-src governs stylesheets. The fallback directive, default-src, covers any fetch categories that are not explicitly defined.
Permissive vs. Restrictive Source Values
Standard CSP source values include 'self' (loads resources from the origin domain), 'none' (blocks everything), and explicit hostnames (like apis.google.com). In contrast, permissive values like 'unsafe-inline' and 'unsafe-eval' allow execution of arbitrary inline scripts and dynamic text, which bypasses core XSS defenses.
Auditing and Monitoring Violations
Setting up a CSP can sometimes break existing functionality if a required source is missed. Developers can deploy policies in dry-run mode using the Content-Security-Policy-Report-Only header. Any violations will trigger POST requests to endpoints defined in report-uri or report-to, letting teams fix issues before enforcing strict blocks.
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Frequently Asked Questions About Content Security Policy
A Content Security Policy is a security standard implemented via HTTP headers that helps detect and mitigate code injection attacks like cross-site scripting and clickjacking. By declaring approved sources of dynamic content, you instruct browsers to download and run only those trusted resources, protecting your users from malicious script executions.
You deploy a Content Security Policy by adding it as a Content-Security-Policy HTTP response header on your web server configuration (like Nginx or Apache), or by declaring it within a meta tag in your HTML file head. Server response headers are the most secure and highly recommended deployment option now.
Yes. Our Content Security Policy Builder runs completely client-side in your local web browser. Your directives, domains, and reporting endpoints are never uploaded to any external server or backend API. All policy definitions are processed privately and compiled securely on your device, ensuring total privacy of your network setup now.
The default-src directive specifies the fallback policy for other CSP fetch directives that you do not define explicitly. By setting default-src to a restrictive value like 'self' or 'none', you ensure the browser blocks unexpected asset types, preventing attackers from exploiting unconfigured resource loaders in your application code files instantly.
The unsafe-inline source value allows the loading and execution of inline scripts and stylesheets. While convenient for rapid styling and script setups, it disables the core XSS protection mechanism of CSP, as malicious scripts injected into HTML pages will be treated as valid and executed by user web browsers directly.
Yes. Setting object-src to none is a critical security recommendation. It completely restricts the loading of plugins like Flash, Java Applets, or PDF embed viewers. Since these legacy plugins are prone to vulnerability exploits, blocking them at the policy level helps reduce the attack surface of your modern applications now.
Report-Only mode, set using the Content-Security-Policy-Report-Only header, monitors policy violations without actually enforcing blocks. The browser will report any policy mismatch via a POST request to your specified endpoint, allowing developers to test and refine their policy configuration safely without breaking any active features on their live sites right now.
Yes. You can load inline scripts by appending a cryptographic nonce (number used once) token to each tag and adding it to script-src. The browser will only execute inline scripts matching the nonce generated per request, allowing required dynamic elements while rejecting static injections from malicious third parties very easily.
The upgrade-insecure-requests directive instructs browsers to treat all of your website's insecure URL resource links (loading over HTTP) as if they were pointing to secure HTTPS instead. This prevents mixed-content warnings and blocks on secure pages, simplifying HTTPS migration across large legacy database asset sets instantly and completely for free.