Great news - Ethernet support for ESP32 has been added for Mongoose OS.

ESP32 includes an Ethernet MAC and requires an external PHY,
connected over RMII interface. Two PHY models are currently supported:

• Microchip LAN87x0 (LAN8710 supports both MII and RMII,
  LAN8720 is RMII only).
• TI TLK110 (PHY model selection is a compile-time option and is set here).

Here is a detailed article on how to connect a PHY yourself, but it is much easier to buy a dev board which already has one, for example Olimex ESP32-EVB:

Once wired, mos config-set eth.enable=true to enable Ethernet. If you're building your own app, make sure to include ethernet library in your mos.yml:

libs:
  - origin: https://github.com/mongoose-os-libs/ethernet
  ...

Questions?
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