Installing Pydantic in Termux requires building from source. The solution: install Rust and wait.

The Problem

Attempting to pip install pydantic in Termux fails because pydantic-core needs to be built from source. No precompiled wheel is available for the Termux environment.

The Solution

Install Rust, pkg install rust then let pip build pydantic-core from source.

The build takes approximately 10 minutes. Let it run in the Termux window without interruption.