chrome.declarativeNetRequest

Description

The chrome.declarativeNetRequest API is used to block or modify network requests by specifying declarative rules. This lets extensions modify network requests without intercepting them and viewing their content, thus providing more privacy.

Permissions

declarativeNetRequest
declarativeNetRequestWithHostAccess

The "declarativeNetRequest" and "declarativeNetRequestWithHostAccess" permissions provide the same capabilities. The differences between them is when permissions are requested or granted.

"declarativeNetRequest"
Triggers a permission warning at install time but provides implicit access to allow, allowAllRequests and block rules. Use this when possible to avoid needing to request full access to hosts.
"declarativeNetRequestFeedback"
Enables debugging features for unpacked extensions, specifically getMatchedRules() and onRuleMatchedDebug.
"declarativeNetRequestWithHostAccess"
A permission warning is not shown at install time, but you must request host permissions before you can perform any action on a host. This is appropriate when you want to use declarative net request rules in an extension which already has host permissions without generating additional warnings.

Availability

Chrome 84+

Manifest

In addition to the permissions described previously, certain types of rulesets, static rulesets specifically, require declaring the "declarative_net_request" manifest key, which should be a dictionary with a single key called "rule_resources". This key is an array containing dictionaries of type Ruleset, as shown in the following. (Note that the name 'Ruleset' does not appear in the manifest's JSON since it is merely an array.) Static rulesets are explained later in this document.

{
  "name": "My extension",
  ...

  "declarative_net_request" : {
    "rule_resources" : [{
      "id": "ruleset_1",
      "enabled": true,
      "path": "rules_1.json"
    }, {
      "id": "ruleset_2",
      "enabled": false,
      "path": "rules_2.json"
    }]
  },
  "permissions": [
    "declarativeNetRequest",
    "declarativeNetRequestFeedback"
  ],
  "host_permissions": [
    "http://www.blogger.com/*",
    "http://*.google.com/*"
  ],
  ...
}

Rules and rulesets

To use this API, specify one or more rulesets. A ruleset contains an array of rules. A single rule does one of the following:

  • Block a network request.
  • Upgrade the schema (http to https).
  • Prevent a request from getting blocked by negating any matching blocked rules.
  • Redirect a network request.
  • Modify request or response headers.

There are three types of rulesets, managed in slightly different ways.

Dynamic
Persist across browser sessions and extension upgrades and are managed using JavaScript while an extension is in use.
Session
Cleared when the browser shuts down and when a new version of the extension is installed. Session rules are managed using JavaScript while an extension is in use.
Static
Packaged, installed, and updated when an extension is installed or upgraded. Static rules are stored in JSON-formatted rule files and listed in the manifest file.

Dynamic and session-scoped rulesets

Dynamic and session rulesets are managed using JavaScript while an extension is in use.

  • Dynamic rules persist across browser sessions and extension upgrades.
  • Session rules are cleared when the browser shuts down and when a new version of the extension is installed.

There is only one each of these ruleset types. An extension can add or remove rules to them dynamically by calling updateDynamicRules() and updateSessionRules(), provided the rule limits aren't exceeded. For information on rule limits, see Rule limits. You can see an example of this under code examples.

Static rulesets

Unlike dynamic and session rules, static rules are packaged, installed, and updated when an extension is installed or upgraded. They're stored in rule files in JSON format, which are indicated to the extension using the "declarative_net_request" and "rule_resources" keys as described above, as well as one or more Ruleset dictionaries. A Ruleset dictionary contains a path to the rule file, an ID for the ruleset contained in the file, and whether the ruleset is enabled or disabled. The last two are important when you enable or disable a ruleset programmatically.

{
  ...
  "declarative_net_request" : {
    "rule_resources" : [{
      "id": "ruleset_1",
      "enabled": true,
      "path": "rules_1.json"
    },
    ...
    ]
  }
  ...
}

To test rule files, load your extension unpacked. Errors and warnings about invalid static rules are only displayed for unpacked extensions. Invalid static rules in packed extensions are ignored.

Expedited review

Changes to static rulesets may be eligible for expedited review. See expedited review for eligible changes.

Enable and disable static rules and rulesets

Both individual static rules and complete static rulesets may be enabled or disabled at runtime.

The set of enabled static rules and rulesets is persisted across browser sessions. Neither are persisted across extension updates, meaning that only rules you chose to leave in your rule files are available after an update.

For performance reasons there are also limits to the number of rules and rulesets that may be enabled at one time. Call getAvailableStaticRuleCount() to check the number of additional rules that may be enabled. For information on rule limits, see Rule limits.

To enable or disable static rules, call updateStaticRules(). This method takes an UpdateStaticRulesOptions object, which contains arrays of IDs of rules to enable or disable. The IDs are defined using the "id" key of the Ruleset dictionary. There is a maximum limit of 5000 disabled static rules.

To enable or disable static rulesets, call updateEnabledRulesets(). This method takes an UpdateRulesetOptions object, which contains arrays of IDs of rulesets to enable or disable. The IDs are defined using the "id" key of the Ruleset dictionary.

Build rules

Regardless of type, a rule starts with four fields as shown in the following. While the "id" and "priority" keys take a number, the "action" and "condition" keys may provide several blocking and redirecting conditions. The following rule blocks all script requests originating from "foo.com" to any URL with "abc" as a substring.

{
  "id" : 1,
  "priority": 1,
  "action" : { "type" : "block" },
  "condition" : {
    "urlFilter" : "abc",
    "initiatorDomains" : ["foo.com"],
    "resourceTypes" : ["script"]
  }
}

URL matching

Declarative Net Request provides the ability to match URLs with either a pattern matching syntax or regular expressions.

URL filter syntax

A rule's "condition" key allows a "urlFilter" key for acting on URLs under a specified domain. You create patterns using pattern matching tokens. Here are a few examples.

urlFilter Matches Does not match
"abc" https://abcd.com
https://example.com/abcd		 https://ab.com
"abc*d" https://abcd.com
https://example.com/abcxyzd		 https://abc.com
"||a.example.com" https://a.example.com/
https://b.a.example.com/xyz
https://a.example.company		 https://example.com/
"|https*" https://example.com http://example.com/
http://https.com
"example*^123|" https://example.com/123
http://abc.com/example?123		 https://example.com/1234
https://abc.com/example0123

Regular expressions

Conditions can also use regular expressions. See the "regexFilter" key. To learn about the limits that apply to these conditions, see Rules that use regular expressions.

Write good URL conditions

Take care when writing rules to always match an entire domain. Otherwise, your rule may match in situations that are unexpected. For example, when using the pattern matching syntax:

  • google.com incorrectly matches https://example.com/?param=google.com
  • ||google.com incorrectly matches https://google.company
  • https://www.google.com incorrectly matches https://example.com/?param=https://www.google.com

Consider using:

  • ||google.com/, which matches all paths and all subdomains.
  • |https://www.google.com/ which matches all paths and no subdomains.

Similarly, use the ^ and / characters to anchor a regular expression. For example, ^https:\/\/www\.google\.com\/ matches any path on https://www.google.com.

Rule evaluation

DNR rules are applied by the browser across various stages of the network request lifecycle.

Before the request

Before a request is made, an extension can block or redirect (including upgrading the scheme from HTTP to HTTPS) it with a matching rule.

For each extension, the browser determines a list of matching rules. Rules with a modifyHeaders action are not included here as they will be handled later. Additionally, rules with a responseHeaders condition will be considered later (when response headers are available) and are not included.

Then, for each extension, Chrome picks at most one candidate per request. Chrome finds a matching rule, by ordering all matching rules by priority. Rules with the same priority are ordered by action (allow or allowAllRequests > block > upgradeScheme > redirect).

If the candidate is an allow or allowAllRequests rule, or the frame the request is being made in previously matched an allowAllRequests rule of higher or equal priority from this extension, the request is "allowed" and the extension won't have any effect on the request.

If more than one extension wants to block or redirect this request, a single action to take is chosen. Chrome does this by sorting the rules in the order block > redirect or upgradeScheme > allow or allowAllRequests. If two rules are of the same type, Chrome chooses the rule from the most recently installed extension.

Before request headers are sent

Before Chrome sends request headers to the server, the headers are updated based on matching modifyHeaders rules.

Within a single extension, Chrome builds the list of modifications to perform by finding all matching modifyHeaders rules. Similar to before, only rules which have a higher priority than any matching allow or allowAllRequests rules are included.

These rules are applied by Chrome in an order such that rules from a more recently installed extension are always evaluated before rules from an older extension. Additionally, rules of a higher priority from one extension are always applied before rules of a lower priority from the same extension. Notably, even across extensions:

  • If a rule appends to a header, then lower priority rules can only append to that header. Set and remove operations are not allowed.
  • If a rule sets a header, then only lower priority rules from the same extension can append to that header. No other modifications are allowed.
  • If a rule removes a header, then lower priority rules cannot further modify the header.

Once a response is received

Once the response headers have been received, Chrome evaluates rules with a responseHeaders condition.

After sorting these rules by action and priority and excluding any rules made redundant by a matching allow or allowAllRequests rule (this happens identically to the steps in "Before the request"), Chrome may block or redirect the request on behalf of an extension.

Note that if a request made it to this stage, the request has already been sent to the server and the server has received data like the request body. A block or redirect rule with a response headers condition will still run–but cannot actually block or redirect the request.

In the case of a block rule, this is handled by the page which made the request receiving a blocked response and Chrome terminating the request early. In the case of a redirect rule, Chrome makes a new request to the redirected URL. Make sure to consider if these behaviors meet the privacy expectations for your extension.

If the request is not blocked or redirected, Chrome applies any modifyHeaders rules. Applying modifications to response headers works in the same way as described in "Before request headers are sent". Applying modifications to request headers does nothing, since the request has already been made.

Safe rules

Safe rules are defined as rules with an action of block, allow, allowAllRequests or upgradeScheme. These rules are subject to an increased dynamic rules quota.

Rule limits

There is a performance overhead to loading and evaluating rules in the browser, so some limits apply when using the API. Limits depend on the type of rule you're using.

Static rules

Static rules are those specified in rule files declared in the manifest file. An extension can specify up to 100 static rulesets as part of the "rule_resources" manifest key, but only 50 of these rulesets can be enabled at a time. The latter is called the MAX_NUMBER_OF_ENABLED_STATIC_RULESETS. Collectively, those rulesets are guaranteed at least 30,000 rules. This is called the GUARANTEED_MINIMUM_STATIC_RULES.

The number of rules available after that depends on how many rules are enabled by all the extensions installed on a user's browser. You can find this number at runtime by calling getAvailableStaticRuleCount(). You can see an example of this under code examples.

Session rules

An extension can have up to 5000 session rules. This is exposed as the MAX_NUMBER_OF_SESSION_RULES.

Before Chrome 120, there was a limit of 5000 combined dynamic and session rules.

Dynamic rules

An extension can have at least 5000 dynamic rules. This is exposed as the MAX_NUMBER_OF_UNSAFE_DYNAMIC_RULES.

Starting in Chrome 121, there is a larger limit of 30,000 rules available for safe dynamic rules, exposed as the MAX_NUMBER_OF_DYNAMIC_RULES. Any unsafe rules added within the limit of 5000 will also count towards this limit.

Before Chrome 120, there was a 5000 combined dynamic and session rules limit.

Rules that use regular expressions

All types of rules can use regular expressions; however, the total number of regular expression rules of each type cannot exceed 1000. This is called the MAX_NUMBER_OF_REGEX_RULES.

Additionally, each rule must be less than 2KB once compiled. This roughly correlates with the complexity of the rule. If you try to load a rule that exceeds this limit, you will see a warning like the following and the rule will be ignored.

rules_1.json: Rule with id 1 specified a more complex regex than allowed
as part of the "regexFilter" key.

Interactions with service workers

A declarativeNetRequest only applies to requests that reach the network stack. This includes responses from the HTTP cache, but may not include responses that go through a service worker's onfetch handler. declarativeNetRequest won't affect responses generated by the service worker or retrieved from CacheStorage, but it will affect calls to fetch() made in a service worker.

Web accessible resources

A declarativeNetRequest rule cannot redirect from a public resource request to a resource that is not web accessible. Doing so triggers an error. This is true even if the specified web accessible resource is owned by the redirecting extension. To declare resources for declarativeNetRequest, use the manifest's "web_accessible_resources" array.

Header modification

The append operation is only supported for the following headers: accept, accept-encoding, accept-language, access-control-request-headers, cache-control, connection, content-language, cookie, forwarded, if-match, if-none-match, keep-alive, range, te, trailer, transfer-encoding, upgrade, user-agent, via, want-digest, x-forwarded-for.

Examples

Code examples

Update dynamic rules

The following example shows how to call updateDynamicRules(). The procedure for updateSessionRules() is the same.

// Get arrays containing new and old rules
const newRules = await getNewRules();
const oldRules = await chrome.declarativeNetRequest.getDynamicRules();
const oldRuleIds = oldRules.map(rule => rule.id);

// Use the arrays to update the dynamic rules
await chrome.declarativeNetRequest.updateDynamicRules({
  removeRuleIds: oldRuleIds,
  addRules: newRules
});

Update static rulesets

The following example shows how to enable and disable rulesets while considering the number of available and the maximum number of enabled static rulesets. You would do this when the number of static rules you need exceeds the number allowed. For this to work, some of your rulesets should be installed with some of your rulesets disabled (setting "Enabled" to false within the manifest file).

async function updateStaticRules(enableRulesetIds, disableCandidateIds) {
  // Create the options structure for the call to updateEnabledRulesets()
  let options = { enableRulesetIds: enableRulesetIds }
  // Get the number of enabled static rules
  const enabledStaticCount = await chrome.declarativeNetRequest.getEnabledRulesets();
  // Compare rule counts to determine if anything needs to be disabled so that
  // new rules can be enabled
  const proposedCount = enableRulesetIds.length;
  if (enabledStaticCount + proposedCount > chrome.declarativeNetRequest.MAX_NUMBER_OF_ENABLED_STATIC_RULESETS) {
    options.disableRulesetIds = disableCandidateIds
  }
  // Update the enabled static rules
  await chrome.declarativeNetRequest.updateEnabledRulesets(options);
}

Rule examples

The following examples illustrate how Chrome prioritizes rules in an extension. When reviewing them, you may want to open the prioritization rules in a separate window.

The "priority" key

These examples require host permission to *://*.example.com/*.

To work out the priority of a particular URL, look at the (developer-defined) "priority" key, the "action" key and the "urlFilter" key. These examples refer to the example rule file shown below them.

Navigation to https://google.com
Two rules cover this URL: the rules with IDs 1 and 4. The rule with ID 1 applies because "block" actions have a higher priority than "redirect" actions. The remaining rules don't apply because they are for longer URLs.
Navigation to https://google.com/1234
Because of the longer URL, the rule with ID 2 now matches in addition to the rules with IDs 1 and 4. The rule with ID 2 applies because "allow" has a higher priority than "block" and "redirect".
Navigation to https://google.com/12345
All four rules match this URL. The rule with ID 3 applies because its developer-defined priority is the highest of the group.
[
  {
    "id": 1,
    "priority": 1,
    "action": { "type": "block" },
    "condition": {"urlFilter": "||google.com/", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 2,
    "priority": 1,
    "action": { "type": "allow" },
    "condition": { "urlFilter": "||google.com/123", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 3,
    "priority": 2,
    "action": { "type": "block" },
    "condition": { "urlFilter": "||google.com/12345", "resourceTypes": ["main_frame"] }
  },
  {
    "id": 4,
    "priority": 1,
    "action": { "type": "redirect", "redirect": { "url": "https://example.com" } },
    "condition": { "urlFilter": "||google.com/", "resourceTypes": ["main_frame"] }
  },
]

Redirects

The example below requires host permission to *://*.example.com/*.

The following example shows how to redirect a request from example.com to a page within the extension itself. The extension path /a.jpg resolves to chrome-extension://EXTENSION_ID/a.jpg, where EXTENSION_ID is the ID of your extension. For this to work the manifest should declare /a.jpg as a web accessible resource.

{
  "id": 1,
  "priority": 1,
  "action": { "type": "redirect", "redirect": { "extensionPath": "/a.jpg" } },
  "condition": {
    "urlFilter": "||https://www.example.com/",
    "resourceTypes": ["main_frame"]
  }
}

The following uses the "transform" key to redirect to a subdomain of example.com. It uses a domain name anchor ("||") to intercept requests with any scheme from example.com. The "scheme" key in "transform" specifies that redirects to the subdomain will always use "https".

{
  "id": 1,
  "priority": 1,
  "action": {
    "type": "redirect",
    "redirect": {
      "transform": { "scheme": "https", "host": "new.example.com" }
    }
  },
  "condition": {
    "urlFilter": "||example.com/",
    "resourceTypes": ["main_frame"]
  }
}

The following example uses regular expressions to redirect from https://www.abc.xyz.com/path to https://abc.xyz.com/path. In the "regexFilter" key, notice how periods are escaped and that the capturing group selects either "abc" or "def". The "regexSubstitution" key specifies the first returned match of the regular expression using "\1". In this case, "abc" is captured from the redirected URL and placed in the substitution.

{
  "id": 1,
  "priority": 1,
  "action": {
    "type": "redirect",
    "redirect": {
      "regexSubstitution": "https://\\1.xyz.com/"
    }
  },
  "condition": {
    "regexFilter": "^https://www\\.(abc|def)\\.xyz\\.com/",
    "resourceTypes": [
      "main_frame"
    ]
  }
}

Headers

The following example removes all cookies from both a main frame and any sub frames.

{
  "id": 1,
  "priority": 1,
  "action": {
    "type": "modifyHeaders",
    "requestHeaders": [{ "header": "cookie", "operation": "remove" }]
  },
  "condition": { "resourceTypes": ["main_frame", "sub_frame"] }
}

Types

DomainType

This describes whether the request is first or third party to the frame in which it originated. A request is said to be first party if it has the same domain (eTLD+1) as the frame in which the request originated.

Enum

"firstParty"
The network request is first party to the frame in which it originated.

"thirdParty"
The network request is third party to the frame in which it originated.

ExtensionActionOptions

Chrome 88+

Properties

  • displayActionCountAsBadgeText

    boolean optional

    Whether to automatically display the action count for a page as the extension's badge text. This preference is persisted across sessions.

  • tabUpdate

    TabActionCountUpdate optional

    Chrome 89+

    Details of how the tab's action count should be adjusted.

GetDisabledRuleIdsOptions

Chrome 111+

Properties

  • rulesetId

    string

    The id corresponding to a static Ruleset.

GetRulesFilter

Chrome 111+

Properties

  • ruleIds

    number[] optional

    If specified, only rules with matching IDs are included.

HeaderInfo

Chrome 128+

Properties

  • excludedValues

    string[] optional

    If specified, this condition is not matched if the header exists but its value contains at least one element in this list. This uses the same match pattern syntax as values.

  • header

    string

    The name of the header. This condition matches on the name only if both values and excludedValues are not specified.

  • values

    string[] optional

    If specified, this condition matches if the header's value matches at least one pattern in this list. This supports case-insensitive header value matching plus the following constructs:

    '*' : Matches any number of characters.

    '?' : Matches zero or one character(s).

    '*' and '?' can be escaped with a backslash, e.g. '\*' and '\?'

HeaderOperation

Chrome 86+

This describes the possible operations for a "modifyHeaders" rule.

Enum

"append"
Adds a new entry for the specified header. This operation is not supported for request headers.

"set"
Sets a new value for the specified header, removing any existing headers with the same name.

"remove"
Removes all entries for the specified header.

IsRegexSupportedResult

Chrome 87+

Properties

  • isSupported

    boolean

  • reason

    UnsupportedRegexReason optional

    Specifies the reason why the regular expression is not supported. Only provided if isSupported is false.

MatchedRule

Properties

  • ruleId

    number

    A matching rule's ID.

  • rulesetId

    string

    ID of the Ruleset this rule belongs to. For a rule originating from the set of dynamic rules, this will be equal to DYNAMIC_RULESET_ID.

MatchedRuleInfo

Properties

  • tabId

    number

    The tabId of the tab from which the request originated if the tab is still active. Else -1.

  • timeStamp

    number

    The time the rule was matched. Timestamps will correspond to the Javascript convention for times, i.e. number of milliseconds since the epoch.

MatchedRuleInfoDebug

Properties

MatchedRulesFilter

Properties

  • minTimeStamp

    number optional

    If specified, only matches rules after the given timestamp.

  • tabId

    number optional

    If specified, only matches rules for the given tab. Matches rules not associated with any active tab if set to -1.

ModifyHeaderInfo

Chrome 86+

Properties

  • header

    string

    The name of the header to be modified.

  • operation

    HeaderOperation

    The operation to be performed on a header.

  • value

    string optional

    The new value for the header. Must be specified for append and set operations.

QueryKeyValue

Properties

  • key

    string

  • replaceOnly

    boolean optional

    Chrome 94+

    If true, the query key is replaced only if it's already present. Otherwise, the key is also added if it's missing. Defaults to false.

  • value

    string

QueryTransform

Properties

  • addOrReplaceParams

    QueryKeyValue[] optional

    The list of query key-value pairs to be added or replaced.

  • removeParams

    string[] optional

    The list of query keys to be removed.

Redirect

Properties

  • extensionPath

    string optional

    Path relative to the extension directory. Should start with '/'.

  • regexSubstitution

    string optional

    Substitution pattern for rules which specify a regexFilter. The first match of regexFilter within the url will be replaced with this pattern. Within regexSubstitution, backslash-escaped digits (\1 to \9) can be used to insert the corresponding capture groups. \0 refers to the entire matching text.

  • transform

    URLTransform optional

    Url transformations to perform.

  • url

    string optional

    The redirect url. Redirects to JavaScript urls are not allowed.

RegexOptions

Chrome 87+

Properties

  • isCaseSensitive

    boolean optional

    Whether the regex specified is case sensitive. Default is true.

  • regex

    string

    The regular expresson to check.

  • requireCapturing

    boolean optional

    Whether the regex specified requires capturing. Capturing is only required for redirect rules which specify a regexSubstition action. The default is false.

RequestDetails

Properties

  • documentId

    string optional

    Chrome 106+

    The unique identifier for the frame's document, if this request is for a frame.

  • documentLifecycle

    DocumentLifecycle optional

    Chrome 106+

    The lifecycle of the frame's document, if this request is for a frame.

  • frameId

    number

    The value 0 indicates that the request happens in the main frame; a positive value indicates the ID of a subframe in which the request happens. If the document of a (sub-)frame is loaded (type is main_frame or sub_frame), frameId indicates the ID of this frame, not the ID of the outer frame. Frame IDs are unique within a tab.

  • frameType

    FrameType optional

    Chrome 106+

    The type of the frame, if this request is for a frame.

  • initiator

    string optional

    The origin where the request was initiated. This does not change through redirects. If this is an opaque origin, the string 'null' will be used.

  • method

    string

    Standard HTTP method.

  • parentDocumentId

    string optional

    Chrome 106+

    The unique identifier for the frame's parent document, if this request is for a frame and has a parent.

  • parentFrameId

    number

    ID of frame that wraps the frame which sent the request. Set to -1 if no parent frame exists.

  • requestId

    string

    The ID of the request. Request IDs are unique within a browser session.

  • tabId

    number

    The ID of the tab in which the request takes place. Set to -1 if the request isn't related to a tab.

  • The resource type of the request.

  • url

    string

    The URL of the request.

RequestMethod

Chrome 91+

This describes the HTTP request method of a network request.

Enum

"connect"

"delete"

"get"

"head"

"options"

"patch"

"post"

"put"

"other"

ResourceType

This describes the resource type of the network request.

Enum

"main_frame"

"sub_frame"

"stylesheet"

"script"

"image"

"font"

"object"

"xmlhttprequest"

"ping"

"csp_report"

"media"

"websocket"

"webtransport"

"webbundle"

"other"

Rule

Properties

  • action

    RuleAction

    The action to take if this rule is matched.

  • condition

    RuleCondition

    The condition under which this rule is triggered.

  • id

    number

    An id which uniquely identifies a rule. Mandatory and should be >= 1.

  • priority

    number optional

    Rule priority. Defaults to 1. When specified, should be >= 1.

RuleAction

Properties

  • redirect

    Redirect optional

    Describes how the redirect should be performed. Only valid for redirect rules.

  • requestHeaders

    ModifyHeaderInfo[] optional

    Chrome 86+

    The request headers to modify for the request. Only valid if RuleActionType is "modifyHeaders".

  • responseHeaders

    ModifyHeaderInfo[] optional

    Chrome 86+

    The response headers to modify for the request. Only valid if RuleActionType is "modifyHeaders".

  • The type of action to perform.

RuleActionType

Describes the kind of action to take if a given RuleCondition matches.

Enum

"block"
Block the network request.

"redirect"
Redirect the network request.

"allow"
Allow the network request. The request won't be intercepted if there is an allow rule which matches it.

"upgradeScheme"
Upgrade the network request url's scheme to https if the request is http or ftp.

"modifyHeaders"
Modify request/response headers from the network request.

"allowAllRequests"
Allow all requests within a frame hierarchy, including the frame request itself.

RuleCondition

Properties

  • domainType

    DomainType optional

    Specifies whether the network request is first-party or third-party to the domain from which it originated. If omitted, all requests are accepted.

  • domains

    string[] optional

    Deprecated since Chrome 101

    Use initiatorDomains instead

    The rule will only match network requests originating from the list of domains.

  • excludedDomains

    string[] optional

    Deprecated since Chrome 101

    Use excludedInitiatorDomains instead

    The rule will not match network requests originating from the list of excludedDomains.

  • excludedInitiatorDomains

    string[] optional

    Chrome 101+

    The rule will not match network requests originating from the list of excludedInitiatorDomains. If the list is empty or omitted, no domains are excluded. This takes precedence over initiatorDomains.

    Notes:

    • Sub-domains like "a.example.com" are also allowed.
    • The entries must consist of only ascii characters.
    • Use punycode encoding for internationalized domains.
    • This matches against the request initiator and not the request url.
    • Sub-domains of the listed domains are also excluded.
  • excludedRequestDomains

    string[] optional

    Chrome 101+

    The rule will not match network requests when the domains matches one from the list of excludedRequestDomains. If the list is empty or omitted, no domains are excluded. This takes precedence over requestDomains.

    Notes:

    • Sub-domains like "a.example.com" are also allowed.
    • The entries must consist of only ascii characters.
    • Use punycode encoding for internationalized domains.
    • Sub-domains of the listed domains are also excluded.
  • excludedRequestMethods

    RequestMethod[] optional

    Chrome 91+

    List of request methods which the rule won't match. Only one of requestMethods and excludedRequestMethods should be specified. If neither of them is specified, all request methods are matched.

  • excludedResourceTypes

    ResourceType[] optional

    List of resource types which the rule won't match. Only one of resourceTypes and excludedResourceTypes should be specified. If neither of them is specified, all resource types except "main_frame" are blocked.

  • excludedResponseHeaders

    HeaderInfo[] optional

    Chrome 128+

    Rule does not match if the request matches any response header condition in this list (if specified). If both excludedResponseHeaders and responseHeaders are specified, then the excludedResponseHeaders property takes precedence.

  • excludedTabIds

    number[] optional

    Chrome 92+

    List of tabs.Tab.id which the rule should not match. An ID of tabs.TAB_ID_NONE excludes requests which don't originate from a tab. Only supported for session-scoped rules.

  • initiatorDomains

    string[] optional

    Chrome 101+

    The rule will only match network requests originating from the list of initiatorDomains. If the list is omitted, the rule is applied to requests from all domains. An empty list is not allowed.

    Notes:

    • Sub-domains like "a.example.com" are also allowed.
    • The entries must consist of only ascii characters.
    • Use punycode encoding for internationalized domains.
    • This matches against the request initiator and not the request url.
    • Sub-domains of the listed domains are also matched.
  • isUrlFilterCaseSensitive

    boolean optional

    Whether the urlFilter or regexFilter (whichever is specified) is case sensitive. Default is false.

  • regexFilter

    string optional

    Regular expression to match against the network request url. This follows the RE2 syntax.

    Note: Only one of urlFilter or regexFilter can be specified.

    Note: The regexFilter must be composed of only ASCII characters. This is matched against a url where the host is encoded in the punycode format (in case of internationalized domains) and any other non-ascii characters are url encoded in utf-8.

  • requestDomains

    string[] optional

    Chrome 101+

    The rule will only match network requests when the domain matches one from the list of requestDomains. If the list is omitted, the rule is applied to requests from all domains. An empty list is not allowed.

    Notes:

    • Sub-domains like "a.example.com" are also allowed.
    • The entries must consist of only ascii characters.
    • Use punycode encoding for internationalized domains.
    • Sub-domains of the listed domains are also matched.
  • requestMethods

    RequestMethod[] optional

    Chrome 91+

    List of HTTP request methods which the rule can match. An empty list is not allowed.

    Note: Specifying a requestMethods rule condition will also exclude non-HTTP(s) requests, whereas specifying excludedRequestMethods will not.

  • resourceTypes

    ResourceType[] optional

    List of resource types which the rule can match. An empty list is not allowed.

    Note: this must be specified for allowAllRequests rules and may only include the sub_frame and main_frame resource types.

  • responseHeaders

    HeaderInfo[] optional

    Chrome 128+

    Rule matches if the request matches any response header condition in this list (if specified).

  • tabIds

    number[] optional

    Chrome 92+

    List of tabs.Tab.id which the rule should match. An ID of tabs.TAB_ID_NONE matches requests which don't originate from a tab. An empty list is not allowed. Only supported for session-scoped rules.

  • urlFilter

    string optional

    The pattern which is matched against the network request url. Supported constructs:

    '*' : Wildcard: Matches any number of characters.

    '|' : Left/right anchor: If used at either end of the pattern, specifies the beginning/end of the url respectively.

    '||' : Domain name anchor: If used at the beginning of the pattern, specifies the start of a (sub-)domain of the URL.

    '^' : Separator character: This matches anything except a letter, a digit, or one of the following: _, -, ., or %. This also match the end of the URL.

    Therefore urlFilter is composed of the following parts: (optional Left/Domain name anchor) + pattern + (optional Right anchor).

    If omitted, all urls are matched. An empty string is not allowed.

    A pattern beginning with ||* is not allowed. Use * instead.

    Note: Only one of urlFilter or regexFilter can be specified.

    Note: The urlFilter must be composed of only ASCII characters. This is matched against a url where the host is encoded in the punycode format (in case of internationalized domains) and any other non-ascii characters are url encoded in utf-8. For example, when the request url is http://abc.рф?q=ф, the urlFilter will be matched against the url http://abc.xn--p1ai/?q=%D1%84.

Ruleset

Properties

  • enabled

    boolean

    Whether the ruleset is enabled by default.

  • id

    string

    A non-empty string uniquely identifying the ruleset. IDs beginning with '_' are reserved for internal use.

  • path

    string

    The path of the JSON ruleset relative to the extension directory.

RulesMatchedDetails

Properties

TabActionCountUpdate

Chrome 89+

Properties

  • increment

    number

    The amount to increment the tab's action count by. Negative values will decrement the count.

  • tabId

    number

    The tab for which to update the action count.

TestMatchOutcomeResult

Chrome 103+

Properties

  • matchedRules

    MatchedRule[]

    The rules (if any) that match the hypothetical request.

TestMatchRequestDetails

Chrome 103+

Properties

  • initiator

    string optional

    The initiator URL (if any) for the hypothetical request.

  • method

    RequestMethod optional

    Standard HTTP method of the hypothetical request. Defaults to "get" for HTTP requests and is ignored for non-HTTP requests.

  • responseHeaders

    object optional

    Chrome 129+

    The headers provided by a hypothetical response if the request does not get blocked or redirected before it is sent. Represented as an object which maps a header name to a list of string values. If not specified, the hypothetical response would return empty response headers, which can match rules which match on the non-existence of headers. E.g. {"content-type": ["text/html; charset=utf-8", "multipart/form-data"]}

  • tabId

    number optional

    The ID of the tab in which the hypothetical request takes place. Does not need to correspond to a real tab ID. Default is -1, meaning that the request isn't related to a tab.

  • The resource type of the hypothetical request.

  • url

    string

    The URL of the hypothetical request.

UnsupportedRegexReason

Chrome 87+

Describes the reason why a given regular expression isn't supported.

Enum

"syntaxError"
The regular expression is syntactically incorrect, or uses features not available in the RE2 syntax.

"memoryLimitExceeded"
The regular expression exceeds the memory limit.

UpdateRuleOptions

Chrome 87+

Properties

  • addRules

    Rule[] optional

    Rules to add.

  • removeRuleIds

    number[] optional

    IDs of the rules to remove. Any invalid IDs will be ignored.

UpdateRulesetOptions

Chrome 87+

Properties

  • disableRulesetIds

    string[] optional

    The set of ids corresponding to a static Ruleset that should be disabled.

  • enableRulesetIds

    string[] optional

    The set of ids corresponding to a static Ruleset that should be enabled.

UpdateStaticRulesOptions

Chrome 111+

Properties

  • disableRuleIds

    number[] optional

    Set of ids corresponding to rules in the Ruleset to disable.

  • enableRuleIds

    number[] optional

    Set of ids corresponding to rules in the Ruleset to enable.

  • rulesetId

    string

    The id corresponding to a static Ruleset.

URLTransform

Properties

  • fragment

    string optional

    The new fragment for the request. Should be either empty, in which case the existing fragment is cleared; or should begin with '#'.

  • host

    string optional

    The new host for the request.

  • password

    string optional

    The new password for the request.

  • path

    string optional

    The new path for the request. If empty, the existing path is cleared.

  • port

    string optional

    The new port for the request. If empty, the existing port is cleared.

  • query

    string optional

    The new query for the request. Should be either empty, in which case the existing query is cleared; or should begin with '?'.

  • queryTransform

    QueryTransform optional

    Add, remove or replace query key-value pairs.

  • scheme

    string optional

    The new scheme for the request. Allowed values are "http", "https", "ftp" and "chrome-extension".

  • username

    string optional

    The new username for the request.

Properties

DYNAMIC_RULESET_ID

Ruleset ID for the dynamic rules added by the extension.

Value

"_dynamic"

GETMATCHEDRULES_QUOTA_INTERVAL

Time interval within which MAX_GETMATCHEDRULES_CALLS_PER_INTERVAL getMatchedRules calls can be made, specified in minutes. Additional calls will fail immediately and set runtime.lastError. Note: getMatchedRules calls associated with a user gesture are exempt from the quota.

Value

10

GUARANTEED_MINIMUM_STATIC_RULES

Chrome 89+

The minimum number of static rules guaranteed to an extension across its enabled static rulesets. Any rules above this limit will count towards the global static rule limit.

Value

30000

MAX_GETMATCHEDRULES_CALLS_PER_INTERVAL

The number of times getMatchedRules can be called within a period of GETMATCHEDRULES_QUOTA_INTERVAL.

Value

20

MAX_NUMBER_OF_DYNAMIC_RULES

The maximum number of dynamic rules that an extension can add.

Value

30000

MAX_NUMBER_OF_ENABLED_STATIC_RULESETS

Chrome 94+

The maximum number of static Rulesets an extension can enable at any one time.

Value

50

MAX_NUMBER_OF_REGEX_RULES

The maximum number of regular expression rules that an extension can add. This limit is evaluated separately for the set of dynamic rules and those specified in the rule resources file.

Value

1000

MAX_NUMBER_OF_SESSION_RULES

Chrome 120+

The maximum number of session scoped rules that an extension can add.

Value

5000

MAX_NUMBER_OF_STATIC_RULESETS

The maximum number of static Rulesets an extension can specify as part of the "rule_resources" manifest key.

Value

100

MAX_NUMBER_OF_UNSAFE_DYNAMIC_RULES

Chrome 120+

The maximum number of "unsafe" dynamic rules that an extension can add.

Value

5000

MAX_NUMBER_OF_UNSAFE_SESSION_RULES

Chrome 120+

The maximum number of "unsafe" session scoped rules that an extension can add.

Value

5000

SESSION_RULESET_ID

Chrome 90+

Ruleset ID for the session-scoped rules added by the extension.

Value

"_session"

Methods

getAvailableStaticRuleCount()

Promise Chrome 89+ 
chrome.declarativeNetRequest.getAvailableStaticRuleCount(
  callback?: function,
)

Returns the number of static rules an extension can enable before the global static rule limit is reached.

Parameters

  • callback

    function optional

    The callback parameter looks like: 

    (count: number) => void

    • count

      number

Returns

  • Promise<number>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

getDisabledRuleIds()

Promise Chrome 111+ 
chrome.declarativeNetRequest.getDisabledRuleIds(
  options: GetDisabledRuleIdsOptions,
  callback?: function,
)

Returns the list of static rules in the given Ruleset that are currently disabled.

Parameters

  • Specifies the ruleset to query.

  • callback

    function optional

    The callback parameter looks like: 

    (disabledRuleIds: number[]) => void

    • disabledRuleIds

      number[]

Returns

  • Promise<number[]>

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

getDynamicRules()

Promise 
chrome.declarativeNetRequest.getDynamicRules(
  filter?: GetRulesFilter,
  callback?: function,
)

Returns the current set of dynamic rules for the extension. Callers can optionally filter the list of fetched rules by specifying a filter.

Parameters

  • filter

    GetRulesFilter optional

    Chrome 111+

    An object to filter the list of fetched rules.

  • callback

    function optional

    The callback parameter looks like: 

    (rules: Rule[]) => void

Returns

  • Promise<Rule[]>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

getEnabledRulesets()

Promise 
chrome.declarativeNetRequest.getEnabledRulesets(
  callback?: function,
)

Returns the ids for the current set of enabled static rulesets.

Parameters

  • callback

    function optional

    The callback parameter looks like: 

    (rulesetIds: string[]) => void

    • rulesetIds

      string[]

Returns

  • Promise<string[]>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

getMatchedRules()

Promise 
chrome.declarativeNetRequest.getMatchedRules(
  filter?: MatchedRulesFilter,
  callback?: function,
)

Returns all rules matched for the extension. Callers can optionally filter the list of matched rules by specifying a filter. This method is only available to extensions with the "declarativeNetRequestFeedback" permission or having the "activeTab" permission granted for the tabId specified in filter. Note: Rules not associated with an active document that were matched more than five minutes ago will not be returned.

Parameters

Returns

  • Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

getSessionRules()

Promise Chrome 90+ 
chrome.declarativeNetRequest.getSessionRules(
  filter?: GetRulesFilter,
  callback?: function,
)

Returns the current set of session scoped rules for the extension. Callers can optionally filter the list of fetched rules by specifying a filter.

Parameters

  • filter

    GetRulesFilter optional

    Chrome 111+

    An object to filter the list of fetched rules.

  • callback

    function optional

    The callback parameter looks like: 

    (rules: Rule[]) => void

Returns

  • Promise<Rule[]>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

isRegexSupported()

Promise Chrome 87+ 
chrome.declarativeNetRequest.isRegexSupported(
  regexOptions: RegexOptions,
  callback?: function,
)

Checks if the given regular expression will be supported as a regexFilter rule condition.

Parameters

Returns

  • Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

setExtensionActionOptions()

Promise Chrome 88+ 
chrome.declarativeNetRequest.setExtensionActionOptions(
  options: ExtensionActionOptions,
  callback?: function,
)

Configures if the action count for tabs should be displayed as the extension action's badge text and provides a way for that action count to be incremented.

Parameters

  • callback

    function optional

    Chrome 89+

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

testMatchOutcome()

Promise Chrome 103+ 
chrome.declarativeNetRequest.testMatchOutcome(
  request: TestMatchRequestDetails,
  callback?: function,
)

Checks if any of the extension's declarativeNetRequest rules would match a hypothetical request. Note: Only available for unpacked extensions as this is only intended to be used during extension development.

Parameters

Returns

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

updateDynamicRules()

Promise 
chrome.declarativeNetRequest.updateDynamicRules(
  options: UpdateRuleOptions,
  callback?: function,
)

Modifies the current set of dynamic rules for the extension. The rules with IDs listed in options.removeRuleIds are first removed, and then the rules given in options.addRules are added. Notes:

  • This update happens as a single atomic operation: either all specified rules are added and removed, or an error is returned.
  • These rules are persisted across browser sessions and across extension updates.
  • Static rules specified as part of the extension package can not be removed using this function.
  • MAX_NUMBER_OF_DYNAMIC_RULES is the maximum number of dynamic rules an extension can add. The number of unsafe rules must not exceed MAX_NUMBER_OF_UNSAFE_DYNAMIC_RULES.

Parameters

  • Chrome 87+
  • callback

    function optional

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

updateEnabledRulesets()

Promise 
chrome.declarativeNetRequest.updateEnabledRulesets(
  options: UpdateRulesetOptions,
  callback?: function,
)

Updates the set of enabled static rulesets for the extension. The rulesets with IDs listed in options.disableRulesetIds are first removed, and then the rulesets listed in options.enableRulesetIds are added. Note that the set of enabled static rulesets is persisted across sessions but not across extension updates, i.e. the rule_resources manifest key will determine the set of enabled static rulesets on each extension update.

Parameters

  • Chrome 87+
  • callback

    function optional

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

updateSessionRules()

Promise Chrome 90+ 
chrome.declarativeNetRequest.updateSessionRules(
  options: UpdateRuleOptions,
  callback?: function,
)

Modifies the current set of session scoped rules for the extension. The rules with IDs listed in options.removeRuleIds are first removed, and then the rules given in options.addRules are added. Notes:

  • This update happens as a single atomic operation: either all specified rules are added and removed, or an error is returned.
  • These rules are not persisted across sessions and are backed in memory.
  • MAX_NUMBER_OF_SESSION_RULES is the maximum number of session rules an extension can add.

Parameters

  • callback

    function optional

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 91+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

updateStaticRules()

Promise Chrome 111+ 
chrome.declarativeNetRequest.updateStaticRules(
  options: UpdateStaticRulesOptions,
  callback?: function,
)

Disables and enables individual static rules in a Ruleset. Changes to rules belonging to a disabled Ruleset will take effect the next time that it becomes enabled.

Parameters

Returns

  • Promise<void>

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

Events

onRuleMatchedDebug

chrome.declarativeNetRequest.onRuleMatchedDebug.addListener(
  callback: function,
)

Fired when a rule is matched with a request. Only available for unpacked extensions with the "declarativeNetRequestFeedback" permission as this is intended to be used for debugging purposes only.

Parameters