CSP

CSP Generator

Generate Content Security Policy headers

Security & Auth

🔒 100% client-side — your data never leaves this page

Maintained by ToolsKit Editorial Team•Updated: March 22, 2026•Reviewed: March 27, 2026

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Policy Input

Quick CTA

Fill the core CSP directives first to generate the policy header; report-uri and scenario comparisons stay in Deep.

default-srcscript-srcstyle-srcimg-srcconnect-src

CSP Output

CSP policy will appear here

🔒 100% client-side

Next step workflow

Build security headers Generate meta tags bundle Check content-type headers

Page reading mode

Deep expands pitfalls, recipes, snippets, FAQ, and related tools when you need troubleshooting or deeper follow-through.

About this tool

Create Content Security Policy rules for modern web apps and output both HTTP header and meta tag formats. This tool helps reduce XSS risk by defining trusted script, style, image, and connect sources. It is useful during security hardening, penetration testing, and production rollout checks.

Direct Answers

Q01

What is the safest baseline when starting a CSP policy?

Start from a restrictive default-src self baseline, then add only the external origins your app truly needs.

Q02

Is report-uri worth enabling?

Yes when you are tightening policy gradually. Reporting helps you see what would break before enforcement becomes painful.

Failure Input Library

Wildcard source silently weakens policy

Bad input: Using `script-src *` to quickly “fix” blocked third-party scripts.

Failure: Policy appears present but offers little effective protection.

Fix: Restrict to explicit trusted origins and remove broad wildcards.

Input assumptions are not normalized

Bad input: Edge payloads omit required fields.

Failure: Output appears valid locally but fails during downstream consumption.

Fix: Normalize contracts and enforce preflight checks before export.

Compatibility boundaries are implicit

Bad input: One-step execution bypasses review checkpoints.

Failure: Same source data yields inconsistent outcomes across environments.

Fix: Declare compatibility constraints and verify with an independent consumer.

Practical Notes

CSP Generator works best when you apply it with clear input assumptions and a repeatable workflow.

Practical usage

Use this tool as part of a repeatable debugging workflow instead of one-off trial and error.

Capture one reproducible input and expected output so teammates can verify behavior quickly.

Engineering tips

Keep tool output in PR comments or issue templates to shorten communication loops.

When behavior changes after deployment, compare old and new outputs with the same fixture data.

Use It In Practice

CSP Generator is most reliable with real inputs and scenario-driven decisions, especially around "Balancing CSP strictness and operational compatibility".

Use Cases

When Balancing CSP strictness and operational compatibility, prioritize Adopt staged rollout with report-only telemetry and explicit allowlists..
When Local exploration and temporary diagnostics, prioritize Use fast pass with lightweight verification..
Compare Strict CSP vs Permissive CSP for Strict CSP vs permissive CSP before implementation.

Quick Steps

Fill in the default, script, style, image, and connect sources your page actually uses.
Enable a reporting endpoint if you want violation visibility during rollout.
Generate the header and test it against real third-party integrations before strict enforcement.

Avoid Common Mistakes

Common failure: Policy appears present but offers little effective protection.
Common failure: Output appears valid locally but fails during downstream consumption.

Scenario Recipes

Build a baseline CSP for a web app

Goal: Generate a practical policy before shipping security headers on a dashboard, marketing site, or SaaS app.

Fill in the default, script, style, image, and connect sources your page actually uses.
Enable a reporting endpoint if you want violation visibility during rollout.
Generate the header and test it against real third-party integrations before strict enforcement.

Result: You move from vague CSP aspirations to a concrete starter policy you can iterate on.

Harden CSP during third-party script cleanup

Goal: Reduce XSS surface while keeping analytics and payments functional.

Inventory all script/style/font origins from real page loads.
Start with report-only policy and inspect blocked resource reports.
Promote to enforcing policy after false positives are resolved.

Result: Security posture improves without breaking core business flows.

Csp Generator readiness pass for cross-team handoff validation

Goal: Validate assumptions before output enters shared workflows.

Run representative samples and capture output structure.
Replay edge cases with downstream acceptance criteria.
Publish only after sample and edge-case checks both pass.

Result: Delivery quality improves with less rollback and rework.

Csp Generator incident replay for legacy contract stabilization

Goal: Convert recurring failures into repeatable diagnostics.

Rebuild problematic inputs in an isolated environment.
Compare expected and actual outputs against explicit pass criteria.
Document reusable runbook steps for on-call and handoff.

Result: Recovery time drops and operational variance shrinks.

Failure Clinic (Common Pitfalls)

Allowing broad sources just to make errors disappear

Cause: Under deadline pressure, teams often add https: or wildcard sources without understanding what broke.

Fix: Expand directives narrowly and use reporting to learn which origins are actually required.

Forgetting app-specific fetch endpoints

Cause: Policies may cover scripts and images but miss API, websocket, or analytics connections.

Fix: Audit connect-src separately so runtime API calls do not fail after rollout.

Production Snippets

Baseline CSP header

http

Content-Security-Policy: default-src 'self'; script-src 'self' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; connect-src 'self' https://api.toolskit.cc

Compare & Decision

Strict CSP vs permissive CSP

Strict CSP

Use it when the app stack is stable and you can maintain a narrow source allowlist.

Permissive CSP

Use it only during transition periods when dependencies are still being discovered.

Note: Permissive policies may reduce breakage today, but strict policies create stronger long-term security boundaries.

Fast pass vs controlled workflow

Fast pass

Use for low-impact exploration and quick local checks.

Controlled workflow

Use for production delivery, audit trails, or cross-team handoff.

Note: Csp Generator is more reliable when acceptance criteria are explicit before release.

Direct execution vs staged validation

Direct execution

Use for disposable experiments and temporary diagnostics.

Stage + verify

Use when outputs will be reused by downstream systems.

Note: Staged validation reduces silent compatibility regressions.

Quick Decision Matrix

Balancing CSP strictness and operational compatibility

Recommend: Adopt staged rollout with report-only telemetry and explicit allowlists.

Avoid: Avoid one-shot strict policies without resource dependency mapping.

Local exploration and temporary diagnostics

Recommend: Use fast pass with lightweight verification.

Avoid: Avoid promoting exploratory output directly to production artifacts.

Production release, compliance, or cross-team handoff

Recommend: Use staged workflow with explicit validation records.

Avoid: Avoid one-step execution without replayable evidence.

Frequently Asked Questions

What is CSP used for?

CSP limits which sources can load scripts and other resources, reducing XSS and injection risks.

Should I use HTTP header or meta tag?

HTTP header is preferred in production. Meta tag can help for static hosting scenarios.

Can CSP break existing pages?

Yes if sources are too strict. Start with report-only strategy and tighten rules gradually.

Can I use this output directly in production?

Yes, but you should still validate output in your real runtime environment before deployment. CSP Generator is designed for fast local verification and clean copy-ready results.

Does this tool run fully client-side?

Yes. All processing happens in your browser and no input is uploaded to a server.

How can I avoid formatting or parsing errors?

Use well-formed input, avoid mixed encodings, and paste minimal reproducible samples first. Then scale to full content after the preview looks correct.