A handler specific parameter string. For example, PDFs might use <kbd>page15-100px</kbd>. <var>$1urlwidth</var> must be used and be consistent with <var>$1urlparam</var>.

Some parameter types in API requests need further explanation:
;boolean
:Boolean parameters work like HTML checkboxes: if the parameter is specified, regardless of value, it is considered true. For a false value, omit the parameter entirely.
;timestamp
:Timestamps may be specified in several formats. ISO 8601 date and time is recommended. All times are in UTC, any included timezone is ignored.
:* ISO 8601 date and time, <kbd><var>2001</var>-<var>01</var>-<var>15</var>T<var>14</var>:<var>56</var>:<var>00</var>Z</kbd> (punctuation and <kbd>Z</kbd> are optional)
:* ISO 8601 date and time with (ignored) fractional seconds, <kbd><var>2001</var>-<var>01</var>-<var>15</var>T<var>14</var>:<var>56</var>:<var>00</var>.<var>00001</var>Z</kbd> (dashes, colons, and <kbd>Z</kbd> are optional)
:* MediaWiki format, <kbd><var>2001</var><var>01</var><var>15</var><var>14</var><var>56</var><var>00</var></kbd>
:* Generic numeric format, <kbd><var>2001</var>-<var>01</var>-<var>15</var> <var>14</var>:<var>56</var>:<var>00</var></kbd> (optional timezone of <kbd>GMT</kbd>, <kbd>+<var>##</var></kbd>, or <kbd>-<var>##</var></kbd> is ignored)
:* EXIF format, <kbd><var>2001</var>:<var>01</var>:<var>15</var> <var>14</var>:<var>56</var>:<var>00</var></kbd>
:*RFC 2822 format (timezone may be omitted), <kbd><var>Mon</var>, <var>15</var> <var>Jan</var> <var>2001</var> <var>14</var>:<var>56</var>:<var>00</var></kbd>
:* RFC 850 format (timezone may be omitted), <kbd><var>Monday</var>, <var>15</var>-<var>Jan</var>-<var>2001</var> <var>14</var>:<var>56</var>:<var>00</var></kbd>
:* C ctime format, <kbd><var>Mon</var> <var>Jan</var> <var>15</var> <var>14</var>:<var>56</var>:<var>00</var> <var>2001</var></kbd>
:* Seconds since 1970-01-01T00:00:00Z as a 1 to 13 digit integer (excluding <kbd>0</kbd>)
:* The string <kbd>now</kbd>

Link to search for. Must be used with <var>$1lang</var>.

Interwiki link to search for. Must be used with <var>$1blprefix</var>.

Interwiki link to search for. Must be used with <var>$1prefix</var>.

Link to search for. Must be used with <var>$1lang</var>.

Interwiki link to search for. Must be used with <var>$1prefix</var>.

Which category to enumerate (required). Must include the <kbd>{{ns:category}}:</kbd> prefix. Cannot be used together with <var>$1pageid</var>.

If <kbd>[[Special:ApiHelp/query+authmanagerinfo|action=query&meta=authmanagerinfo]]</kbd> returned true for <samp>hasprimarypreservedstate</samp>, requests marked as <samp>primary-required</samp> should be omitted. If it returned a non-empty value for <samp>preservedusername</samp>, that username must be used for the <var>username</var> parameter.

Une chaîne de paramètre spécifique à l’analyseur. Par exemple, les PDFs peuvent utiliser <kbd>page15-100px</kbd>. <var>$1urlwidth</var> doit être utilisé et être cohérent avec <var>$1urlparam</var>.

Unha cadea de parámetro específico no analizador. Por exemplo, os PDFs poden usar <kbd>page15-100px</kbd>. Debe usarse <var>$1urlwidth</var> que debe ser coherente con <var>$1urlparam</var>.

Cannot be used with <var>$3user</var>.

Parameter "$1" must be a string

Parse the content of this page. Cannot be used together with <var>$1text</var> and <var>$1title</var>.

Sortkey prefix to start listing from. Can only be used with <kbd>$1sort=sortkey</kbd>. Overrides <var>$1starthexsortkey</var>.

ID of the block to unblock (obtained through <kbd>list=blocks</kbd>). Cannot be used together with <var>$1user</var>.

ID of the block to unblock (obtained through <kbd>list=blocks</kbd>). Cannot be used together with <var>$1user</var>.

May only be used with <var>$3user</var>.

מחרוזת פרמטר ייחודית למטפל. למשל, PDF־ים יכולים להשתמש ב־<kbd>page15-100px</kbd>.‏ <var>$1urlwidth</var> צריך לשמש ולהיות עקבי עם <var>$1urlparam</var>.

Рядок окремого параметра. Наприклад, PDF-ки можуть використовувати <kbd>page15-100px</kbd>. <var>$1urlwidth</var> повинно використовуватись і бути сумісним з <var>$1urlparam</var>.

Modules to display help for (values of the <var>action</var> and <var>format</var> parameters, or <kbd>main</kbd>). Can specify submodules with a <kbd>+</kbd>.

Perform a prefix search for page titles.

Despite the similarity in names, this module is not intended to be equivalent to [[Special:PrefixIndex]]; for that, see <kbd>[[Special:ApiHelp/query+allpages|action=query&list=allpages]]</kbd> with the <kbd>apprefix</kbd> parameter. The purpose of this module is similar to <kbd>[[Special:ApiHelp/opensearch|action=opensearch]]</kbd>: to take user input and provide the best-matching titles. Depending on the search engine backend, this might include typo correction, redirect avoidance, or other heuristics.

Parses content and returns parser output.

See the various prop-modules of <kbd>[[Special:ApiHelp/query|action=query]]</kbd> to get information from the current version of a page.

There are several ways to specify the text to parse:
# Specify a page or revision, using <var>$1page</var>, <var>$1pageid</var>, or <var>$1oldid</var>.
# Specify content explicitly, using <var>$1text</var>, <var>$1title</var>, and <var>$1contentmodel</var>.
# Specify only a summary to parse. <var>$1prop</var> should be given an empty value.

The general procedure to use this module is:
# Fetch the fields available from <kbd>[[Special:ApiHelp/query+authmanagerinfo|action=query&meta=authmanagerinfo]]</kbd> with <kbd>amirequestsfor=$4</kbd>, and a <kbd>$5</kbd> token from <kbd>[[Special:ApiHelp/query+tokens|action=query&meta=tokens]]</kbd>.
# Present the fields to the user, and obtain their submission.
# Post to this module, supplying <var>$1returnurl</var> and any relevant fields.
# Check the <samp>status</samp> in the response.
#* If you received <samp>PASS</samp> or <samp>FAIL</samp>, you're done. The operation either succeeded or it didn't.
#* If you received <samp>UI</samp>, present the new fields to the user and obtain their submission. Then post to this module with <var>$1continue</var> and the relevant fields set, and repeat step 4.
#* If you received <samp>REDIRECT</samp>, direct the user to the <samp>redirecttarget</samp> and wait for the return to <var>$1returnurl</var>. Then post to this module with <var>$1continue</var> and any fields passed to the return URL, and repeat step 4.
#* If you received <samp>RESTART</samp>, that means the authentication worked but we don't have a linked user account. You might treat this as <samp>UI</samp> or as <samp>FAIL</samp>.

Title of page the text belongs to. If omitted, <var>$1contentmodel</var> must be specified, and [[API]] will be used as the title.