Permissions-Policy Header Builder
Permissions-Policy Header Builder: Constructs W3C Feature Policy / Permissions Policy header directives restricting browser capabilities.
About this permissions-policy header builder
Permissions-Policy Header Builder — browser-based utility.
How this tool works
Implements client-side Permissions-Policy Header Builder operations. Constructs W3C Feature Policy / Permissions Policy header directives restricting browser capabilities specifically designed for a web architect builds a permissions-policy header to disable camera, microphone, and geolocation apis.
- Token Structure Extraction: Splits JWT strings on '.' delimiters into Header, Payload, and Signature segments.
- Base64URL Decoding: Decodes URL-safe Base64 segments into raw JSON strings without executing unverified signature payloads.
- Claims Parsing & Timestamp Evaluation: Parses registered claims ('exp', 'nbf', 'iat', 'iss', 'aud') and checks current clock validity.
- Cryptographic Status Reporting: Displays token signature algorithm (RS256, HS256, ES256, EdDSA) and warns that client decoding does not verify cryptographic signatures without the public key.
Worked example
Scenario: Serialize two documented Permissions-Policy directives from JSON.
Sample input:
Processing: Validate feature tokens, join origins inside parentheses, and join directives with comma-space.
Illustrative output:
Limits and verification
Rejects strings that do not contain exactly two '.' delimiters. Explicitly informs the user that client-side decoding inspects token claims but CANNOT verify mathematical signature validity unless the corresponding public key/secret is supplied.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the Permissions-Policy Header Builder workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What JSON shape does Permissions-Policy Builder accept?+
It reads a JSON object with a features object. Each feature name must match lowercase letters, digits, and hyphens; each origins value may be an array or one scalar string.
How is a directive serialized?+
For each feature, the tool joins origins with spaces inside parentheses and joins directives with comma-space. camera ["'self'"] and microphone [] produce Permissions-Policy: camera=('self'), microphone=().
What did the browser fixture verify?+
The frozen page produced exactly that header for the camera and microphone JSON fixture. It verifies this local string builder, not a browser permission decision.
Which policy behavior is outside scope?+
It does not query a device, enforce a header, parse every specification edge case, model iframe allow attributes, inspect server responses, or prove that a feature is blocked.