Fava supports extensions. Extensions allow you to register hooks and generate your own report pages.

If you use this extension system and need it to do more or need other hooks, please open an issue on GitHub.

A Fava extension is simply a Python module which contains a class that inherits from FavaExtensionBase from fava.ext. Invoking an extension is done via the fava-extension option in the beancount file. Check out fava.ext.auto_commit for an example.

Extensions may also contain a report - this is detected when the extension's class has a report_title attribute. The template for the report should be in a templates subdirectory with a report matching the class's name. For example, check out fava.ext.portfolio_list which has its template located at fava/ext/portfolio_list/templates/PortfolioList.html.

Finally, extensions may contain a Javascript module to be loaded in the frontend. The module should be in a Javascript file matching the class's name and the extension should have its has_js_module attribte set to True. The module can define functions to be called when different events happen. Take a look at fava/ext/portfolio_list/PortfolioList.js for an example. Currently, the following events/functions can be specified:

  • init: is called when a Fava report is first opened
  • onPageLoad: Is called when any page in Fava is loaded (so on first open and on any further navigation).
  • onExtensionPageLoad: Is called when the extension report is loaded.

The whole extension system should be considered unstable and it might change drastically.

Fava Extension Setup Options


A Python module to load as extension. The path of the Beancount file is searched in addition to anything on the Python path. Single python files will also be searched - so for example a my_extension.py could be used by giving my_extension. Note that Python has a global namespace for currently loaded modules, so try avoiding simple names that might coincide with some Python library (as well as running Fava on two files that have different extensions of the same name).

Extensions allow for an optional configuration options string, whose structure is specified by the individual extension.


Below is a list of all current hooks.


Called after a ledger file has been loaded. Use the self.ledger object to access the ledger data.


Called when starting to process a request. Use Flaskā€™s request object to access the request being processed (from flask import request).

after_write_source(path: str, source: str)

Called after the string source has been written to the Beancount file at path.

after_insert_metadata(entry: Directive, key: str, value: str)

Called after metadata (key: value) has been added to an entry.

after_insert_entry(entry: Directive)

Called after an entry has been inserted.

after_entry_modified(entry: Directive, new_lines: str)

Called after an entry has been modified, e.g., via the context popup.

after_delete_entry(entry: Directive)

Called after an entry has been deleted, e.g., via the context popup.

Extension attributes


Optional attribute to set extension report title used in the sidebar.