This is an ACME client for ESP (ESP32, etc) devices, so your IoT can fetch their own certificate for secure communication. ACME is a protocol (see <a href="https://tools.ietf.org/html/rfc8555">RFC8555</a>) for automatic certificate management. Sites such as letsencrypt.org allow you to obtain free (no charge) certificates in an automated way using the ACME protocol. Now also supporting the ARI protocol, to learn about when to renew a certificate. Also works with Google ACME, next to Letsencrypt.
Tiny dependency-free wire-framing codec: CRC-32 length-delimited typed frames with an incremental, resynchronizing StreamParser for carrying messages over any raw byte stream (USB/CDC/socket/UART)
Multiplex several framed protocols (OTA, crash-dump, CAN bridge, app control, ...) over one byte stream: parses the stream_frame codec once and routes each frame to a per-module handler by the frame's module byte