Developing add-ons

Add-ons are way to customize localization workflow in Weblate.

class weblate.addons.base.BaseAddon(storage: Addon)

Base class for Weblate add-ons.

classmethod can_install(component: Component, user: User | None)

Check whether add-on is compatible with given component.

component_update(component: Component) None

Event handler for component update.

configure(configuration) None

Save configuration.

daily(component: Component) None

Event handler daily.

classmethod get_add_form(user: User | None, *, component: Component | None = None, project: Project | None = None, **kwargs)

Return configuration form for adding new add-on.

get_settings_form(user: User | None, **kwargs)

Return configuration form for this add-on.

post_add(translation: Translation) None

Event handler after new translation is added.

post_commit(component: Component) None

Event handler after changes are committed to the repository.

post_push(component: Component) None

Event handler after repository is pushed upstream.

post_update(component: Component, previous_head: str, skip_push: bool, child: bool) None

Event handler after repository is updated from upstream.

  • previous_head (str) – HEAD of the repository prior to update, can be blank on initial clone.

  • skip_push (bool) – Whether the add-on operation should skip pushing changes upstream. Usually you can pass this to underlying methods as commit_and_push or commit_pending.

pre_commit(translation: Translation, author: User) None

Event handler before changes are committed to the repository.

pre_push(component: Component) None

Event handler before repository is pushed upstream.

pre_update(component: Component) None

Event handler before repository is updated from upstream.

save_state() None

Save add-on state information.

store_post_load(translation: Unit, store: TranslationFormat) None

Event handler after a file is parsed.

It receives an instance of a file format class as a argument.

This is useful to modify file format class parameters, for example adjust how the file will be saved.

unit_pre_create(unit: Unit) None

Event handler before new unit is created.


Weblate user used to track changes by this add-on.

class weblate.addons.base.Addon

ORM object for an add-on.

class weblate.addons.base.Component

ORM object for a component.

class weblate.addons.base.Translation

ORM object for a translation.

class weblate.addons.base.Project

ORM object for a project.

class weblate.addons.base.Unit

ORM object for an unit.

class weblate.addons.base.User

ORM object for an user.

class weblate.addons.base.TranslationFormat

Translation file wrapper.

Here is an example add-on:

# Copyright © Michal Čihař <>
# SPDX-License-Identifier: GPL-3.0-or-later

from django.utils.translation import gettext_lazy

from weblate.addons.base import BaseAddon
from import AddonEvent

class ExampleAddon(BaseAddon):
    # Filter for compatible components, every key is
    # matched against property of component
    compat = {"file_format": {"po", "po-mono"}}
    # List of events add-on should receive
    events = (AddonEvent.EVENT_PRE_COMMIT,)
    # Add-on unique identifier
    name = "weblate.example.example"
    # Verbose name shown in the user interface
    verbose = gettext_lazy("Example add-on")
    # Detailed add-on description
    description = gettext_lazy("This add-on does nothing it is just an example.")

    # Callback to implement custom behavior
    def pre_commit(self, translation, author) -> None: