How to use this developer tool
- Paste or upload the expected source text.
- Review any options shown below the input.
- Select Deduplicate Sources or press Ctrl/Cmd + Enter.
- Check the notes, then copy or download the output.
CSP Source List Deduplicator
Remove repeated source expressions from each directive in a CSP policy without alphabetizing or changing the first occurrence. Directive names are compared case-insensitively, and duplicate directives are folded together. The result is easier to review in configuration files and response headers. This cleanup does not assess whether a source is trustworthy, whether host patterns overlap, or whether nonce and hash values are current.
Developer Input
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What this developer tool does
CSP Source List Deduplicator turns the entered source into a structured or generated result that can be inspected before use.
Groups directives by normalized name and performs exact token deduplication while retaining first-seen order.
Input stays in this browser tab. Always remove live secrets before sharing screenshots or downloaded results.
Example
Input
script-src 'self' https://cdn.example.com https://cdn.example.com 'nonce-abc' 'self'; img-src data: https://images.example.com data:
Running the sample produces output that reflects the parsed fields and reports any unsupported or security-sensitive detail.
Use cases
- Translate copied API documentation into project code.
- Inspect request, response, or header configuration during debugging.
- Create a reviewable draft for tests and documentation.
- Spot malformed, duplicate, or overly broad values before deployment.
Tips for reliable output
- Remove real tokens, cookies, and API keys before pasting.
- Keep quoted values intact when copying shell commands.
- Read warnings instead of assuming every option was converted.
- Test generated code against a staging endpoint first.
- Review browser and server security rules separately.
Processing details
Groups directives by normalized name and performs exact token deduplication while retaining first-seen order. Processing is deterministic except where cryptographic random values are intentionally generated.
This browser tool does not execute remote requests, expand shell variables, inspect server behavior, or replace application-specific security review.
Frequently asked questions
Does CSP Source List Deduplicator send my input to a server?
No. Processing runs in the browser and the page does not transmit the entered text.
What input does CSP Source List Deduplicator support?
Paste a CSP policy with repeated sources using the syntax shown in the sample.
Can I use the generated output in production?
Use it as a reviewed starting point. Environment-specific security, authentication, and error handling still need verification.
Why might CSP Source List Deduplicator report a limitation?
The parser handles documented common syntax and reports constructs that would require shell, browser, or server context.
How can I verify the CSP Source List Deduplicator result?
Compare the parsed URL, headers, body, directives, or origins with the source and test the final configuration in a non-production environment.
Related developer tools
Output fields
| Field | Meaning |
|---|---|
| Output | Generated or parsed text |
| Summary | Counts and completion state |
| Notes | Warnings and review guidance |
HTTP & Security Headers
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