LwM2M

LwM2M (Lightweight M2M), standardized by the Open Mobile Alliance, is a device-management and service-enablement protocol built for constrained IoT devices — the low-power, low-bandwidth hardware that cannot afford heavy HTTP stacks. It runs on CoAP over UDP (and increasingly other transports) and defines a compact object model so a management server can remotely provision, monitor, and control fleets of devices. The goal is a single, interoperable way to manage IoT devices across vendors.

• CoAP-based transport - Lightweight request/response designed for lossy, low-power networks rather than HTTP.
• Standardized object model - Registered objects and resources give every device a predictable, addressable structure.
• Full device lifecycle - Bootstrap, registration, firmware update, and remote read/write/execute operations.
• Security bindings - DTLS and OSCORE protect communication between device and management server.

LwM2M matters in the API conversation because it is effectively the management API for the constrained edge of the IoT world — where REST-over-HTTP is too expensive and a purpose-built protocol wins. Its registered object model is a form of contract, much like an OpenAPI definition is for web APIs, and that structure is what makes large device estates governable, observable, and — increasingly — legible to automated and agentic systems reasoning over IoT infrastructure.