Full-stack embeddednetworking library

Embedded TCP/IP stack

// Built-in stack and driver
#define MG_ENABLE_TCPIP 1
#define MG_ENABLE_DRIVER_STM32H 1

Dual IPv4/IPv6 stack. Built-in drivers for STM32, NXP i.MX RT, RW612 and RP2350. Or run on top of lwIP or Zephyr.

Built-in TLS 1.3

#define MG_TLS MG_TLS_BUILTIN
// MG_TLS_MBED    to use mbedTLS
// MG_TLS_WOLFSSL to use WolfSSL
// MG_TLS_OPENSSL to use OpenSSL

HTTPS, WSS are built-in. Mutual TLS supported. TLS takes +50Kb flash, +10 Kb RAM per connection. Fast sub-100ms handshakes on ARM

Embedded web server

mg_http_listen(&mgr, "http://0.0.0.0:80", fn, NULL);,

// In fn(), on MG_EV_HTTP_MSG:
mg_http_reply(c, 200, "", "Hello\n");

HTTP server and client. REST APIs, static files from an embedded filesystem, file uploads, JWT auth, firmware OTA updates.

WebSocket

// In fn(), on MG_EV_HTTP_MSG:
mg_ws_upgrade(c, hm, NULL);

// Later, push data to the browser:
mg_ws_send(c, "hello", 5, WEBSOCKET_OP_TEXT);

Server and client, plain or over TLS. Push live data to a browser or a cloud service over one connection. Over 25k msgs/sec on STM32H7!

MQTT client and server

mg_mqtt_connect(&mgr, "mqtts://broker:8883", &opts, fn, NULL);,

// In fn(), on MG_EV_MQTT_OPEN:
opts.topic = mg_str("dev1/status");
opts.message = mg_str("online");
mg_mqtt_pub(c, &opts);

MQTT 3.1.1 and 5, plain or over TLS. Guides for AWS IoT, Azure IoT Hub and EMQX.

Network services

long t = mg_json_get_long(json, "$.temp", 0);
mg_snprintf(buf, sizeof(buf), "{%m:%ld}",
            MG_ESC("temp"), t);

SNTP, DNS, mDNS, DNS-SD, Modbus-TCP server, JSON parser and printer, JSON-RPC, JWT. Raw TCP and UDP for custom protocols.

Firmware OTA updates

bool mg_ota_begin(size_t size);
bool mg_ota_write(const void *buf, size_t n);
bool mg_ota_end(void);

Streams straight to flash, checks ECDSA-P256 signatures, then swaps banks. STM32, ESP32, RP2040/RP2350, NXP, Renesas, WCH.

mDash device management

#define MG_ENABLE_MDASH 1
#define MG_MDASH_KEY "..."
#define MG_FIRMWARE_VERSION "myfw.1.0"

Cloud backend for fleet OTA updates, remote control and health monitoring. Enabled in mongoose_config.h. Managed at mdash.net or installed on your own servers.

Security and CRA

// Reject firmware without our signature
#define MG_OTA_PUBLIC_KEY { \
  0x19, 0x7f, 0xed, 0x81, 0x8b, 0xb7, \
  ...

Security reports come in every month and get fixed. Commercial users get fixes before CVEs go public. OTA updates have signature checks and authentication, as the EU CRA expects.

Device dashboard

Dashboard API connects device data to a browser UI: realtime data display, setting panels, user auth, file uploads, firmware update. Write the UI by hand or with AI, or build it in Mongoose Wizard, a no-code builder that generates a ready-to-build project.

AI-assisted development

# AGENTS.md
- Read mongoose.h first.
- Use public APIs from mongoose.h only.
- Prefer existing examples over
  invented patterns.

The whole API, with docstrings and examples, is in mongoose.h and fits in one context window. AGENTS.md tells coding agents how to use it, llms.txt summarises Mongoose for LLMs.

One library means one small, coherent API instead of several unrelated ones. The docstrings live in the header, so AI tools need no separate MCP server and write better code on the first try.

Supported platforms

// mongoose_config.h
#define MG_ARCH MG_ARCH_CUBE
// or MG_ARCH_ZEPHYR, MG_ARCH_ESP32,
//    MG_ARCH_PICOSDK, MG_ARCH_UNIX

Bare metal, FreeRTOS, Zephyr, ThreadX, CMSIS-RTOS, RT-Thread, TI-RTOS, embedded Linux, Windows, macOS. Already on lwIP or Zephyr? Mongoose runs on top of it.