---
title: Blocking content with your Safari web extension
framework: safariservices
role: article
role_heading: Article
path: safariservices/blocking-content-with-your-safari-web-extension
---

# Blocking content with your Safari web extension

Build content blocking with declarative net request into your Safari web extension.

## Overview

Overview Add declarative content blocking that works in Safari, Mac web apps, and other browsers to your Safari web extension. This approach blocks content quickly and ensures privacy for users, because the web extension doesn’t need access to the entire web request to make blocking decisions. Safari web extensions implement declarative content blocking with the Declarative Net Request API common to web extensions on other browsers. Request permission to block content To use the Declarative Net Request API in your Safari web extension, first request permission. In your Xcode project, add the declarative net request permission to the permissions list in your manifest.js file. {  ...    "permissions": [     "declarativeNetRequest",     "activeTab"   ],   ... } For more information about permissions, see Managing Safari web extension permissions. Add rulesets to your extension and manifest You specify rules for content blocking in rulesets, which are files with json describing the content blocking rules. Add references to ruleset files that you create in your manifest.js file to tell Safari to use them. For example: {    ...    "declarative_net_request" : {     "rule_resources" : [{       "id": "ruleset_for_images",       "enabled": true,       "path": "image_rules.json"     }, {       "id": "ruleset_for_scripts",       "enabled": false,       "path": "script_rules.json"     }]   },   ... } Build your rules describing how you want to block content, and add them to your ruleset files. For example: {     "id": 1,     "priority": 1,     "action": { "type": "block" },     "condition": {         "regexFilter": ".*",         "resourceTypes": [ "script" ]     } }

Review Safari’s support for specifying rules: Adjust rules dynamically for the extension or session After a user installs and uses your extension, adjust content blocking using dynamic rules. Add, change, or remove rules that persist between browser sessions using updateDynamicRules. Add, change, or remove rules that apply only to the current session using updateSessionRules. var rule = {     id: 1,     priority: 1,     action: { type: "block" },     condition: {         urlFilter: "||example.com",         resourceTypes: [ "main_frame", "script" ]     } };

await browser.declarativeNetRequest.updateDynamicRules({ addRules: [ rule ] });

## See Also

### Blocking content

- [Adopting Declarative Content Blocking in Safari Web Extensions](safariservices/adopting-declarative-content-blocking-in-safari-web-extensions.md)