application registry

A registry of configuration information consulted by Pyramid while servicing an application. An application registry maps resource types to views, as well as housing other application-specific component registrations. Every Pyramid application has one (and only one) application registry.


Any file contained within a Python package which is not a Python source code file.

asset specification

A colon-delimited identifier for an asset. The colon separates a Python package name from a package subpath. For example, the asset specification my.package:static/baz.css identifies the file named baz.css in the static subdirectory of the my.package Python package. See Understanding Asset Specifications for more info.

authentication policy

An authentication policy in Pyramid terms is a bit of code which has an API which determines the current principal (or principals) associated with a request.

authorization policy

An authorization policy in Pyramid terms is a bit of code which has an API which determines whether or not the principals associated with the request can perform an action associated with a permission, based on the information found on the context resource.

configuration declaration

An individual method call made to an instance of a Pyramid Configurator object which performs an arbitrary action, such as registering a view configuration (via the add_view method of the configurator) or route configuration (via the add_route method of the configurator).

configuration decoration

Metadata implying one or more configuration declaration invocations. Often set by configuration Python decorator attributes, such as pyramid.view.view_config, aka @view_config.


An object used to do configuration declaration within an application. The most common configurator is an instance of the pyramid.config.Configurator class.


A wrapper around a Python function or class which accepts the function or class as its first argument and which returns an arbitrary object. Pyramid provides several decorators, used for configuration and return value modification purposes. See also PEP 318.

Default Locale Name

The locale name used by an application when no explicit locale name is set. See Localization-Related Deployment Settings.

default permission

A permission which is registered as the default for an entire application. When a default permission is in effect, every view configuration registered with the system will be effectively amended with a permission argument that will require that the executing user possess the default permission in order to successfully execute the associated view callable See also Setting a Default Permission.

Default view

The default view of a resource is the view invoked when the view name is the empty string (''). This is the case when traversal exhausts the path elements in the PATH_INFO of a request before it returns a context resource.

dotted Python name

A reference to a Python object by name using a string, in the form Often used in Paste and setuptools configurations. A variant is used in dotted names within ZCML attributes that name objects (such as the ZCML "view" directive's "view" attribute): the colon (:) is not used; in its place is a dot.

Exception view

An exception view is a view callable which may be invoked by Pyramid when an exception is raised during request processing. See Custom Exception Views for more information.

Forbidden view

An exception view invoked by Pyramid when the developer explicitly raises a pyramid.exceptions.Forbidden exception from within view code or root factory code, or when the view configuration and authorization policy found for a request disallows a particular view invocation. Pyramid provides a default implementation of a forbidden view; it can be overridden. See Changing the Forbidden View.

imperative configuration

The configuration mode in which you use Python to call methods on a Configurator in order to add each configuration declaration required by your application.

Locale Name

A string like en, en_US, de, or de_AT which uniquely identifies a particular locale.

Locale Negotiator

An object supplying a policy determining which locale name best represents a given request. It is used by the pyramid.i18n.get_locale_name(), and pyramid.i18n.negotiate_locale_name() functions, and indirectly by pyramid.i18n.get_localizer(). The pyramid.i18n.default_locale_negotiator() function is an example of a locale negotiator.


A Python source file; a file on the filesystem that typically ends with the extension .py or .pyc. Modules often live in a package.

Not Found view

An exception view invoked by Pyramid when the developer explicitly raises a pyramid.exceptions.NotFound exception from within view code or root factory code, or when the current request doesn't match any view configuration. Pyramid provides a default implementation of a not found view; it can be overridden. See Changing the Not Found View.


A directory on disk which contains an file, making it recognizable to Python as a location which can be import -ed. A package exists to contain module files.


A lightweight Python web framework.


A web framework.


A serializer that can be referred to via view configuration which converts a non-Response return values from a view into a string (and ultimately a response). Using a renderer can make writing views that require templating or other serialization less tedious. See Writing View Callables Which Use a Renderer for more information.

renderer factory

A factory which creates a renderer. See Adding and Changing Renderers for more information.


A WebOb request object. See Request and Response Objects (narrative) and pyramid.request (API documentation) for information about request objects.

Resource Location

The act of locating a context resource given a request. Traversal and URL dispatch are the resource location subsystems used by Pyramid.

root factory

The "root factory" of an Pyramid application is called on every request sent to the application. The root factory returns the traversal root of an application. It is conventionally named get_root. An application may supply a root factory to Pyramid during the construction of a Configurator. If a root factory is not supplied, the application uses a default root object. Use of the default root object is useful in application which use URL dispatch for all URL-to-view code mappings.


A single pattern matched by the url dispatch subsystem, which generally resolves to one or more view callable objects. See also url dispatch.

route configuration

Route configuration is the act of using imperative configuration or a ZCML <route> statement to associate request parameters with a particular route using pattern matching and route predicate statements. See URL Dispatch for more information about route configuration.

route predicate

An argument to a route configuration which implies a value that evaluates to True or False for a given request. All predicates attached to a route configuration must evaluate to True for the associated route to "match" the current request. If a route does not match the current request, the next route (in definition order) is attempted.


The WSGI application created when you start a Pyramid application. The router intercepts requests, invokes traversal and/or URL dispatch, calls view functions, and returns responses to the WSGI server on behalf of your Pyramid application.


The term used by Pyramid to define the process of importing and examining all code in a Python package or module for configuration decoration.

Translation Directory

A translation directory is a gettext translation directory. It contains language folders, which themselves contain LC_MESSAGES folders, which contain .mo files. Each .mo file represents a set of translations for a language in a translation domain. The name of the .mo file (minus the .mo extension) is the translation domain name.

Translation Domain

A string representing the "context" in which a translation was made. For example the word "java" might be translated differently if the translation domain is "programming-languages" than would be if the translation domain was "coffee". A translation domain is represnted by a collection of .mo files within one or more translation directory directories.


The act of descending "up" a tree of resource objects from a root resource in order to find a context resource. The Pyramid router performs traversal of resource objects when a root factory is specified. See the Traversal chapter for more information. Traversal can be performed instead of URL dispatch or can be combined with URL dispatch. See Combining Traversal and URL Dispatch for more information about combining traversal and URL dispatch (advanced).

URL dispatch

An alternative to traversal as a mechanism for locating a a view callable. When you use a route in your Pyramid application via a route configuration, you are using URL dispatch. See the URL Dispatch for more information.


Common vernacular for a view callable.

view callable

A "view callable" is a callable Python object which is associated with a view configuration; it returns a response object . A view callable accepts a single argument: request, which will be an instance of a request object. A view callable is the primary mechanism by which a developer writes user interface code within Pyramid. See Views for more information about Pyramid view callables.

view configuration

View configuration is the act of associating a view callable with configuration information. This configuration information helps map a given request to a particular view callable and it can influence the response of a view callable. Pyramid views can be configured via imperative configuration, ZCML or by a special @view_config decorator coupled with a scan. See View Configuration for more information about view configuration.

View handler

A view handler ties together pyramid.config.Configurator.add_route() and pyramid.config.Configurator.add_view() to make it more convenient to register a collection of views as a single class when using url dispatch. See also Views.

view mapper

A view mapper is a class which implements the pyramid.interfaces.IViewMapperFactory interface, which performs view argument and return value mapping. This is a plug point for extension builders, not normally used by "civilians".

view name

The "URL name" of a view, e.g index.html. If a view is configured without a name, its name is considered to be the empty string (which implies the default view).

view predicate

An argument to a view configuration which evaluates to True or False for a given request. All predicates attached to a view configuration must evaluate to true for the associated view to be considered as a possible callable for a given request.


Web Server Gateway Interface. This is a Python standard for connecting web applications to web servers, similar to the concept of Java Servlets. Pyramid requires that your application be served as a WSGI application.


Zope Configuration Markup Language, an XML dialect used by Zope and Pyramid for configuration tasks. ZCML is capable of performing different types of configuration declaration, but its primary purpose in Pyramid is to perform view configuration and route configuration within the configure.zcml file in a Pyramid application. You can use ZCML as an alternative to imperative configuration.

ZCML declaration

The concrete use of a ZCML directive within a ZCML file.

ZCML directive

A ZCML "tag" such as <view> or <route>.

Zope Component Architecture

The Zope Component Architecture (aka ZCA) is a system which allows for application pluggability and complex dispatching based on objects which implement an interface. Pyramid uses the ZCA "under the hood" to perform view dispatching and other application configuration tasks.