{"title":"System check framework","version":"5.1","locale":"en","docname":"ref/checks","url":"/en/5.1/ref/checks/","canonical":"https://djangodocs.dev/en/5.1/ref/checks/","summary":"The system check framework is a set of static checks for validating Django projects. It detects common problems and provides hints for how to fix them. The…","html":"

System check frameworkLink to this heading#

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The system check framework is a set of static checks for validating Django\nprojects. It detects common problems and provides hints for how to fix them.\nThe framework is extensible so you can easily add your own checks.

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For details on how to add your own checks and integrate them with Django’s\nsystem checks, see the System check topic guide.

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API referenceLink to this heading#

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CheckMessageLink to this heading#

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\nclass CheckMessage(level, msg, hint=None, obj=None, id=None)Link to this definition#
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The warnings and errors raised by system checks must be instances of\nCheckMessage. An instance encapsulates a single reportable error or\nwarning. It also provides context and hints applicable to the message, and a\nunique identifier that is used for filtering purposes.

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Constructor arguments are:

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level

The severity of the message. Use one of the predefined values: DEBUG,\nINFO, WARNING, ERROR, CRITICAL. If the level is greater or\nequal to ERROR, then Django will prevent management commands from\nexecuting. Messages with level lower than ERROR (i.e. warnings) are\nreported to the console, but can be silenced.

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msg

A short (less than 80 characters) string describing the problem. The string\nshould not contain newlines.

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hint

A single-line string providing a hint for fixing the problem. If no hint\ncan be provided, or the hint is self-evident from the error message, the\nhint can be omitted, or a value of None can be used.

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obj

Optional. An object providing context for the message (for example, the\nmodel where the problem was discovered). The object should be a model,\nfield, or manager or any other object that defines a __str__() method.\nThe method is used while reporting all messages and its result precedes the\nmessage.

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id

Optional string. A unique identifier for the issue. Identifiers should\nfollow the pattern applabel.X001, where X is one of the letters\nCEWID, indicating the message severity (C for criticals, E for\nerrors and so). The number can be allocated by the application, but should\nbe unique within that application.

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There are subclasses to make creating messages with common levels easier. When\nusing them you can omit the level argument because it is implied by the\nclass name.

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\nclass Debug(msg, hint=None, obj=None, id=None)Link to this definition#
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\nclass Info(msg, hint=None, obj=None, id=None)Link to this definition#
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\nclass Warning(msg, hint=None, obj=None, id=None)Link to this definition#
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\nclass Error(msg, hint=None, obj=None, id=None)Link to this definition#
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\nclass Critical(msg, hint=None, obj=None, id=None)Link to this definition#
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Builtin tagsLink to this heading#

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Django’s system checks are organized using the following tags:

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Some checks may be registered with multiple tags.

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Core system checksLink to this heading#

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Asynchronous supportLink to this heading#

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The following checks verify your setup for Asynchronous support:

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Backwards compatibilityLink to this heading#

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Compatibility checks warn of potential problems that might occur after\nupgrading Django.

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CachesLink to this heading#

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The following checks verify that your CACHES setting is correctly\nconfigured:

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DatabaseLink to this heading#

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MySQL and MariaDBLink to this heading#

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If you’re using MySQL or MariaDB, the following checks will be performed:

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    \n

  • mysql.E001: MySQL/MariaDB does not allow unique CharFields to have a\nmax_length > 255. This check was changed to mysql.W003 in Django\n3.1 as the real maximum size depends on many factors.

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  • mysql.W002: MySQL/MariaDB Strict Mode is not set for database connection\n<alias>. See also Setting sql_mode.

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  • mysql.W003: MySQL/MariaDB may not allow unique CharFields to have a\nmax_length > 255.

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Managing filesLink to this heading#

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The following checks verify your setup for Managing files:

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Model fieldsLink to this heading#

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File fieldsLink to this heading#

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  • fields.E200: unique is not a valid argument for a FileField.\nThis check is removed in Django 1.11.

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  • fields.E201: primary_key is not a valid argument for a FileField.

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  • fields.E202: FileField’s upload_to argument must be a relative\npath, not an absolute path.

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  • fields.E210: Cannot use ImageField because Pillow is not installed.

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Related fieldsLink to this heading#

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    \n

  • fields.E300: Field defines a relation with model <model>, which is\neither not installed, or is abstract.

    • \n

  • fields.E301: Field defines a relation with the model\n<app_label>.<model> which has been swapped out.

    • \n

  • fields.E302: Reverse accessor <related model>.<accessor name> for\n<app_label>.<model>.<field name> clashes with field name\n<app_label>.<model>.<field name>.

    • \n

  • fields.E303: Reverse query name for <app_label>.<model>.<field name>\nclashes with field name <app_label>.<model>.<field name>.

    • \n

  • fields.E304: Reverse accessor <related model>.<accessor name> for\n<app_label>.<model>.<field name> clashes with reverse accessor for\n<app_label>.<model>.<field name>.

    • \n

  • fields.E305: Reverse query name for <app_label>.<model>.<field name>\nclashes with reverse query name for <app_label>.<model>.<field name>.

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  • fields.E306: The name <name> is invalid related_name for field\n<model>.<field name>.

    • \n

  • fields.E307: The field <app label>.<model>.<field name> was declared\nwith a lazy reference to <app label>.<model>, but app <app label>\nisn’t installed or doesn’t provide model <model>.

    • \n

  • fields.E308: Reverse query name <related query name> must not end\nwith an underscore.

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  • fields.E309: Reverse query name <related query name> must not contain\n'__'.

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  • fields.E310: No subset of the fields <field1>, <field2>, … on\nmodel <model> is unique.

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  • fields.E311: <model>.<field name> must be unique because it is\nreferenced by a ForeignKey.

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  • fields.E312: The to_field <field name> doesn’t exist on the\nrelated model <app label>.<model>.

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  • fields.E320: Field specifies on_delete=SET_NULL, but cannot be null.

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  • fields.E321: The field specifies on_delete=SET_DEFAULT, but has no\ndefault value.

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  • fields.E330: ManyToManyFields cannot be unique.

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  • fields.E331: Field specifies a many-to-many relation through model\n<model>, which has not been installed.

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  • fields.E332: Many-to-many fields with intermediate tables must not be\nsymmetrical. This check appeared before Django 3.0.

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  • fields.E333: The model is used as an intermediate model by <model>,\nbut it has more than two foreign keys to <model>, which is ambiguous.\nYou must specify which two foreign keys Django should use via the\nthrough_fields keyword argument.

    • \n

  • fields.E334: The model is used as an intermediate model by <model>,\nbut it has more than one foreign key from <model>, which is ambiguous.\nYou must specify which foreign key Django should use via the\nthrough_fields keyword argument.

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  • fields.E335: The model is used as an intermediate model by <model>,\nbut it has more than one foreign key to <model>, which is ambiguous.\nYou must specify which foreign key Django should use via the\nthrough_fields keyword argument.

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  • fields.E336: The model is used as an intermediary model by <model>,\nbut it does not have foreign key to <model> or <model>.

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  • fields.E337: Field specifies through_fields but does not provide the\nnames of the two link fields that should be used for the relation through\n<model>.

    • \n

  • fields.E338: The intermediary model <through model> has no field\n<field name>.

    • \n

  • fields.E339: <model>.<field name> is not a foreign key to <model>.

    • \n

  • fields.E340: The field’s intermediary table <table name> clashes with\nthe table name of <model>/<model>.<field name>.

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  • fields.W340: null has no effect on ManyToManyField.

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  • fields.W341: ManyToManyField does not support validators.

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  • fields.W342: Setting unique=True on a ForeignKey has the same\neffect as using a OneToOneField.

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  • fields.W343: limit_choices_to has no effect on ManyToManyField\nwith a through model. This check appeared before Django 4.0.

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  • fields.W344: The field’s intermediary table <table name> clashes with\nthe table name of <model>/<model>.<field name>.

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  • fields.W345: related_name has no effect on ManyToManyField with a\nsymmetrical relationship, e.g. to “self”.

    • \n

  • fields.W346: db_comment has no effect on ManyToManyField.

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ModelsLink to this heading#

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SecurityLink to this heading#

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The security checks do not make your site secure. They do not audit code, do\nintrusion detection, or do anything particularly complex. Rather, they help\nperform an automated, low-hanging-fruit checklist, that can help you to improve\nyour site’s security.

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Some of these checks may not be appropriate for your particular deployment\nconfiguration. For instance, if you do your HTTP to HTTPS redirection in a load\nbalancer, it’d be irritating to be constantly warned about not having enabled\nSECURE_SSL_REDIRECT. Use SILENCED_SYSTEM_CHECKS to\nsilence unneeded checks.

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The following checks are run if you use the check --deploy option:

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The following checks verify that your security-related settings are correctly\nconfigured:

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SignalsLink to this heading#

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TemplatesLink to this heading#

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The following checks verify that your TEMPLATES setting is correctly\nconfigured:

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TranslationLink to this heading#

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The following checks are performed on your translation configuration:

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URLsLink to this heading#

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The following checks are performed on your URL configuration:

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contrib app checksLink to this heading#

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adminLink to this heading#

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Admin checks are all performed as part of the admin tag.

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The following checks are performed on any\nModelAdmin (or subclass) that is registered\nwith the admin site:

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ModelAdminLink to this heading#

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The following checks are performed on any\nModelAdmin that is registered\nwith the admin site:

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    \n

  • admin.E101: The value of save_as must be a boolean.

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  • admin.E102: The value of save_on_top must be a boolean.

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  • admin.E103: The value of inlines must be a list or tuple.

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  • admin.E104: <InlineModelAdmin class> must inherit from\nInlineModelAdmin.

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  • admin.E105: <InlineModelAdmin class> must have a model attribute.

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  • admin.E106: The value of <InlineModelAdmin class>.model must be a\nModel.

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  • admin.E107: The value of list_display must be a list or tuple.

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  • admin.E108: The value of list_display[n] refers to <label>, which\nis not a callable or attribute of <ModelAdmin class>, or an attribute,\nmethod, or field on <model>.

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  • admin.E109: The value of list_display[n] must not be a many-to-many\nfield or a reverse foreign key.

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  • admin.E110: The value of list_display_links must be a list, a tuple,\nor None.

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  • admin.E111: The value of list_display_links[n] refers to <label>,\nwhich is not defined in list_display.

    • \n

  • admin.E112: The value of list_filter must be a list or tuple.

    • \n

  • admin.E113: The value of list_filter[n] must inherit from\nListFilter.

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  • admin.E114: The value of list_filter[n] must not inherit from\nFieldListFilter.

    • \n

  • admin.E115: The value of list_filter[n][1] must inherit from\nFieldListFilter.

    • \n

  • admin.E116: The value of list_filter[n] refers to <label>,\nwhich does not refer to a Field.

    • \n

  • admin.E117: The value of list_select_related must be a boolean,\ntuple or list.

    • \n

  • admin.E118: The value of list_per_page must be an integer.

    • \n

  • admin.E119: The value of list_max_show_all must be an integer.

    • \n

  • admin.E120: The value of list_editable must be a list or tuple.

    • \n

  • admin.E121: The value of list_editable[n] refers to <label>,\nwhich is not a field of <model>.

    • \n

  • admin.E122: The value of list_editable[n] refers to <label>,\nwhich is not contained in list_display.

    • \n

  • admin.E123: The value of list_editable[n] cannot be in both\nlist_editable and list_display_links.

    • \n

  • admin.E124: The value of list_editable[n] refers to the first field\nin list_display (<label>), which cannot be used unless\nlist_display_links is set.

    • \n

  • admin.E125: The value of list_editable[n] refers to <field name>,\nwhich is not editable through the admin.

    • \n

  • admin.E126: The value of search_fields must be a list or tuple.

    • \n

  • admin.E127: The value of date_hierarchy refers to <field name>,\nwhich does not refer to a Field.

    • \n

  • admin.E128: The value of date_hierarchy must be a DateField or\nDateTimeField.

    • \n

  • admin.E129: <modeladmin> must define a has_<foo>_permission()\nmethod for the <action> action.

    • \n

  • admin.E130: __name__ attributes of actions defined in\n<modeladmin> must be unique. Name <name> is not unique.

    • \n
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InlineModelAdminLink to this heading#

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The following checks are performed on any\nInlineModelAdmin that is registered as an\ninline on a ModelAdmin.

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    \n

  • admin.E201: Cannot exclude the field <field name>, because it is the\nforeign key to the parent model <app_label>.<model>.

    • \n

  • admin.E202: <model> has no ForeignKey to <parent model>./\n<model> has more than one ForeignKey to <parent model>. You must\nspecify a fk_name attribute.

    • \n

  • admin.E203: The value of extra must be an integer.

    • \n

  • admin.E204: The value of max_num must be an integer.

    • \n

  • admin.E205: The value of min_num must be an integer.

    • \n

  • admin.E206: The value of formset must inherit from\nBaseModelFormSet.

    • \n
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GenericInlineModelAdminLink to this heading#

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The following checks are performed on any\nGenericInlineModelAdmin that is\nregistered as an inline on a ModelAdmin.

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    \n

  • admin.E301: 'ct_field' references <label>, which is not a field\non <model>.

    • \n

  • admin.E302: 'ct_fk_field' references <label>, which is not a\nfield on <model>.

    • \n

  • admin.E303: <model> has no GenericForeignKey.

    • \n

  • admin.E304: <model> has no GenericForeignKey using content type\nfield <field name> and object ID field <field name>.

    • \n
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AdminSiteLink to this heading#

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The following checks are performed on the default\nAdminSite:

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authLink to this heading#

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contenttypesLink to this heading#

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The following checks are performed when a model contains a\nGenericForeignKey or\nGenericRelation:

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postgresLink to this heading#

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The following checks are performed on django.contrib.postgres model\nfields:

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sitesLink to this heading#

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The following checks are performed on any model using a\nCurrentSiteManager:

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The following checks verify that django.contrib.sites is correctly\nconfigured:

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staticfilesLink to this heading#

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The following checks verify that django.contrib.staticfiles is correctly\nconfigured:

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","rootId":"system-check-framework","toc":[{"title":"API reference","anchor":"api-reference","children":[{"title":"CheckMessage","anchor":"checkmessage","children":[]}]},{"title":"Builtin tags","anchor":"builtin-tags","children":[]},{"title":"Core system checks","anchor":"core-system-checks","children":[{"title":"Asynchronous support","anchor":"asynchronous-support","children":[]},{"title":"Backwards compatibility","anchor":"backwards-compatibility","children":[]},{"title":"Caches","anchor":"caches","children":[]},{"title":"Database","anchor":"database","children":[{"title":"MySQL and MariaDB","anchor":"mysql-and-mariadb","children":[]}]},{"title":"Managing files","anchor":"managing-files","children":[]},{"title":"Model fields","anchor":"model-fields","children":[{"title":"File fields","anchor":"file-fields","children":[]},{"title":"Related fields","anchor":"related-fields","children":[]}]},{"title":"Models","anchor":"models","children":[]},{"title":"Security","anchor":"security","children":[]},{"title":"Signals","anchor":"signals","children":[]},{"title":"Templates","anchor":"templates","children":[]},{"title":"Translation","anchor":"translation","children":[]},{"title":"URLs","anchor":"urls","children":[]}]},{"title":"contrib app checks","anchor":"contrib-app-checks","children":[{"title":"admin","anchor":"admin","children":[{"title":"ModelAdmin","anchor":"modeladmin","children":[]},{"title":"InlineModelAdmin","anchor":"inlinemodeladmin","children":[]},{"title":"GenericInlineModelAdmin","anchor":"genericinlinemodeladmin","children":[]},{"title":"AdminSite","anchor":"adminsite","children":[]}]},{"title":"auth","anchor":"auth","children":[]},{"title":"contenttypes","anchor":"contenttypes","children":[]},{"title":"postgres","anchor":"postgres","children":[]},{"title":"sites","anchor":"sites","children":[]},{"title":"staticfiles","anchor":"staticfiles","children":[]}]}],"breadcrumbs":[{"docname":"ref/index","title":"API Reference","url":"/en/5.1/ref/"}],"prev":{"docname":"ref/applications","title":"Applications","url":"/en/5.1/ref/applications/"},"next":{"docname":"ref/class-based-views/index","title":"Built-in class-based views API","url":"/en/5.1/ref/class-based-views/"},"formats":{"html":"/en/5.1/ref/checks/","markdown":"/en/5.1/ref/checks.md","json":"/en/5.1/ref/checks.json"},"source":"https://github.com/django/django/blob/stable/5.1.x/docs/ref/checks.txt","official":"https://docs.djangoproject.com/en/5.1/ref/checks/","inVersions":["dev","6.1","6.0","5.2","5.1","5.0","4.2","4.1","4.0","3.2","3.1","3.0","2.2","2.1","2.0","1.11","1.10","1.9","1.8"],"inLocales":["en","zh-hans","fr","ja","id","it","pt-br","ko","es","el","pl"]}