A method of automated conversion of an input declarative representation of a user interface into an output declarative representation of the user interface of a different format, the method comprising: receiving the input declarative representation of the user interface, wherein the input declarative representation of the user interface is of a first hierarchical, declarative format; receiving a selection of a second hierarchical, declarative format; identifying a hierarchical arrangement of templates designated for user interface representation conversion to the second hierarchical, declarative format, wherein the templates process respective hierarchical levels in the output declarative representation of the user interface; and converting the input declarative representation of the user interface into the output declarative representation of the user interface, wherein the converting comprises: executing a plurality of parsing instructions configured to parse declarative user interface representations of the input declarative user interface representation format to provide input element types and/or values to the templates; executing the hierarchical arrangement of templates, wherein the executing comprises: dividing mapping work among the templates according to a hierarchical level in the output declarative representation to which a template is dedicated; and mapping user interface elements in the input declarative representation of the user interface to user interface elements in the output declarative representation of the user interface according to the templates using template helpers including mapping instructions that define the conversion between elements of one declarative format to another declarative format, wherein the parsing instructions are used by the mapping instructions to get the context of elements in the input declarative user interface representation and return the element to be mapped. receiving the input declarative representation of the user interface, wherein the input declarative representation of the user interface is of a first hierarchical, declarative format; receiving a selection of a second hierarchical, declarative format; identifying a hierarchical arrangement of templates designated for user interface representation conversion to the second hierarchical, declarative format, wherein the templates process respective hierarchical levels in the output declarative representation of the user interface; and converting the input declarative representation of the user interface into the output declarative representation of the user interface, wherein the converting comprises: executing a plurality of parsing instructions configured to parse declarative user interface representations of the input declarative user interface representation format to provide input element types and/or values to the templates; executing the hierarchical arrangement of templates, wherein the executing comprises: dividing mapping work among the templates according to a hierarchical level in the output declarative representation to which a template is dedicated; and mapping user interface elements in the input declarative representation of the user interface to user interface elements in the output declarative representation of the user interface according to the templates using template helpers including mapping instructions that define the conversion between elements of one declarative format to another declarative format, wherein the parsing instructions are used by the mapping instructions to get the context of elements in the input declarative user interface representation and return the element to be mapped. executing a plurality of parsing instructions configured to parse declarative user interface representations of the input declarative user interface representation format to provide input element types and/or values to the templates; executing the hierarchical arrangement of templates, wherein the executing comprises: dividing mapping work among the templates according to a hierarchical level in the output declarative representation to which a template is dedicated; and mapping user interface elements in the input declarative representation of the user interface to user interface elements in the output declarative representation of the user interface according to the templates using template helpers including mapping instructions that define the conversion between elements of one declarative format to another declarative format, wherein the parsing instructions are used by the mapping instructions to get the context of elements in the input declarative user interface representation and return the element to be mapped. dividing mapping work among the templates according to a hierarchical level in the output declarative representation to which a template is dedicated; and mapping user interface elements in the input declarative representation of the user interface to user interface elements in the output declarative representation of the user interface according to the templates using template helpers including mapping instructions that define the conversion between elements of one declarative format to another declarative format, wherein the parsing instructions are used by the mapping instructions to get the context of elements in the input declarative user interface representation and return the element to be mapped.