---
title: 'Level 15: Customize the trainer'
description: In this level you'll learn to modify the behavior of the Trainer.
canonical: 'https://lightning.ai/docs/pytorch/stable/level-up/advanced/advanced_level_16'
---
# Level 15: Customize the trainer {#level-15-customize-the-trainer}

In this level you'll learn to modify the behavior of the Trainer.

- [Create and use Callbacks](/docs/pytorch/2.6.6/reference/extensions/callbacks.md) — Modify Trainer behavior with reusable, self-contained code.

- [Customize the progress bar](/docs/pytorch/2.6.6/reference/common/progress_bar.md) — Create beautiful custom progress bars.

---

**Navigation**

- Parent: [Advanced skills](/docs/pytorch/2.6.6/level-up/advanced.md)