docs: Add Content Security Policy requirements for Web SDK #344
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Add CSP documentation explaining the wasm-unsafe-eval requirement for PowerSync Web SDK. This addresses a common production deployment issue where PowerSync fails in Safari due to missing CSP directives. Key additions: - Explanation of why wasm-unsafe-eval is required - Security considerations and comparison to unsafe-eval - Browser compatibility information - Links to official WASM CSP documentation Resolves customer support inquiry about CSP requirements. Co-Authored-By: Craft Agent <agents-noreply@craft.do>
Relocate Content Security Policy documentation from early in the document to the Developer Notes section for better organization. Co-Authored-By: Craft Agent <agents-noreply@craft.do>
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In addition to this change I've also put together a test which verifies this: |
rkistner
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Jan 29, 2026
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Not clear here - does it also work if you just have no CSP at all?
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I believe it should just work if you have no CSP specified. I could verify this by testing a PowerSync web app hosted on Github pages (which does not send a Content Security Header response) From looking at the attached demo script. It seems like a CSP is defined for both cases. So I assume a CSP is required to trigger this. I imagine having a CSP is quite common, but, I agree - we should make a note about this in the docs. |
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Summary
Adds comprehensive Content Security Policy (CSP) documentation for the PowerSync Web SDK, specifically covering the
wasm-unsafe-evalrequirement.Changes
client-sdks/reference/javascript-web.mdxwasm-unsafe-evalCSP directiveunsafe-evalContext
This addresses a common production deployment issue where PowerSync fails in Safari when the
wasm-unsafe-evalCSP directive is missing. Security teams often flag this directive due to XSS concerns, but it's actually more secure thanunsafe-evalas it only permits WebAssembly compilation, not JavaScript eval.Placement
Positioned this in the
Developer Notessection of the Web SDK docs.Related
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