ultralytics/docs/en/reference/utils/callbacks/base.md

description	keywords
Discover the essential base callbacks in Ultralytics for training, validation, prediction, and exporting models efficiently.	Ultralytics, base callbacks, training, validation, prediction, model export, ML, machine learning, deep learning

Reference for ultralytics/utils/callbacks/base.py

!!! Note

This file is available at [https://github.com/ultralytics/ultralytics/blob/main/ultralytics/utils/callbacks/base.py](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/utils/callbacks/base.py). If you spot a problem please help fix it by [contributing](https://docs.ultralytics.com/help/contributing/) a [Pull Request](https://github.com/ultralytics/ultralytics/edit/main/ultralytics/utils/callbacks/base.py) 🛠️. Thank you 🙏!

::: ultralytics.utils.callbacks.base.on_pretrain_routine_start

::: ultralytics.utils.callbacks.base.on_pretrain_routine_end

::: ultralytics.utils.callbacks.base.on_train_start

::: ultralytics.utils.callbacks.base.on_train_epoch_start

::: ultralytics.utils.callbacks.base.on_train_batch_start

::: ultralytics.utils.callbacks.base.optimizer_step

::: ultralytics.utils.callbacks.base.on_before_zero_grad

::: ultralytics.utils.callbacks.base.on_train_batch_end

::: ultralytics.utils.callbacks.base.on_train_epoch_end

::: ultralytics.utils.callbacks.base.on_fit_epoch_end

::: ultralytics.utils.callbacks.base.on_model_save

::: ultralytics.utils.callbacks.base.on_train_end

::: ultralytics.utils.callbacks.base.on_params_update

::: ultralytics.utils.callbacks.base.teardown

::: ultralytics.utils.callbacks.base.on_val_start

::: ultralytics.utils.callbacks.base.on_val_batch_start

::: ultralytics.utils.callbacks.base.on_val_batch_end

::: ultralytics.utils.callbacks.base.on_val_end

::: ultralytics.utils.callbacks.base.on_predict_start

::: ultralytics.utils.callbacks.base.on_predict_batch_start

::: ultralytics.utils.callbacks.base.on_predict_batch_end

::: ultralytics.utils.callbacks.base.on_predict_postprocess_end

::: ultralytics.utils.callbacks.base.on_predict_end

::: ultralytics.utils.callbacks.base.on_export_start

::: ultralytics.utils.callbacks.base.on_export_end

::: ultralytics.utils.callbacks.base.get_default_callbacks

::: ultralytics.utils.callbacks.base.add_integration_callbacks