Python
04 Sep 2026
8 min read
Use Slotted Dataclasses When Object Shape Is Fixed in Python
Python dataclasses reduce boilerplate for record-like classes, but their instances are still ordinary Python objects by default. Declared fields normally live in an instance dictionary, and new attributes can be attached later. That flexibility is useful until the model is supposed to have a fixed shape. Coordinates, parsed records, configuration snapshots, protocol messages, and other compact value objects often have a known set of fields. When many such objects exist, keeping dynamic per-instance attribute storage may also be unnecessary.