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Unexpected Maker NANOS3 might be the world’s tiniest ESP32-S3 module, yet fully-featured
(unexpectedmaker.com)
Everything microcontrollers: projects, questions, new releases, etc.
dragontamer's Beginner Guides:
Beginner Series I: What is a Microcontroller?
Beginner Series II: The "Generic" Microcontroller
Beginner Sidenote: Microchip's Signal Chain Design Guide
Beginner Series III: Skills and Complexity Tiers
Beginner Series IV: Deep Dive into Microchip's AVR EA
That does look to be about as small as you can make one without using an ESP32-S3 with internal flash.