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Last Updated: Jun 29, 2020


The Link Kit SDK for C is intended for devices that use C to develop product logic. Currently most of the IoT devices are using Language C for product development, because Language C has a faster running speed and needs less memory compared to other programming languages.

Get version 2.3.0 of the Link Kit SDK

If the program is implemented by an older version of the SDK (below 2.3.0) and you want to upgrade the SDK, please be sure to read the Interface Change Records to see if the program needs to be changed accordingly.

List of SDK features

The following table lists the features in the latest version of the Link Kit SDK for C.Note: The table does not provide a detailed description of each feature. A feature will be described in detail in the development section of the corresponding feature.

Functional module
Function point
Connect devices to cloud
  • MQTT-based connection to cloud, devices can choose to connect to Alibaba Cloud IoT Platform through MQTT
  • CoAP-based connection to cloud, devices can choose to connect to Alibaba Cloud IoT Platform through CoAP
  • HTTP/S-based connection to cloud, devices can choose to connect to Alibaba Cloud IoT Platform through HTTP/S
  • HTTP2 file upload, enable file upload through HTTP2
Device identity authentication
  • Unique-certificate-per-device authentication
  • Unique-certificate-per-product authentication
Thing specification language
  • Property reporting, property setup
  • Service calls
  • Event reporting
Cloud region configuration
  • Specified by manufacturers, the manufacturers of the cloud sites choose to connect to Alibaba Cloud; for example, East China 2, Singapore, US West, and France
  • Dynamic connection to cloud, devices automatically connect to the cloud sites with the lowest latency
  • Device firmware upgrade
  • Device configuration file acquisition
Sub-device management
  • Sub-device addition and deletion
  • Sub-device identity authentication
  • Sub-device thing specification language agent
Wi-Fi Provisioning
  • One-Time-Configuration Provisioning
  • Phose-As-AP Provisioning
  • Router Provisioning
  • Zero-Time_Configuration Provisioning
Device local control
  • ALCS Server, Controlled-end implementation
  • ALCS Client, Controlling-end implementation
Device-binding support
Maintenance of binding token, cloud synchronization, and response to app queries
Device shadows
Specify cloud storage device information for apps to query
Reset support
  • Online real-time reporting
  • Offline reset support
Obtain time
Obtain real time from the cloud

List of historical versions

Version number
Release date
Download link
Update content
  • Added unique-certificate-per-product authentication/dynamic registration feature:
  • Added offline countdown routine
  • Added OTA to download firmware using iTLS: Using HTTPS to download firmware is no longer required when iTLS/ID2 is enabled
  • Open-source release of Wi-Fi network distribution feature
  • Open-source release of local communication feature
  • Offline reset support
  • Simplified version of TSL support
  • Device enable/disable support
  • TSL array supports objects type
  • MQTT overseas multi-site connection support
  • MQTT bulk subscription for thing specification language
  • HTTP2 file upload support
  • iTLS support
  • CoAP PSK-based authentication and encryption
  • DTLS session reuse of CoAP
  • Unified single product/gateway processing
  • Added Cmake compile system
  • Added thing specification language support
  • Sub-device management support
  • Optimized HTTP flow
  • Optimized TLS, fixed memory leak issues
  • Upgraded MQTT channel to support longer topics and more subscription requests, and MQTT supports multiple threads
  • Added mbedtls support, currently adapted for Linux and Windows systems
  • Optimized the HTTP interface to enable the continuous opening of TLS connections when sending packets
  • Added OpenSSL adaptation
  • Supports the compiling of Win7 libraries and routines using mingw32
  • make reconfig can pop up and select adapted platforms
  • Added OTA based on CoAP notification method
  • Added a cloud-connected channel for HTTP + TLS
  • Refined OTA status
  • Fixed the errors that the SDK reported when compiling in armcc compiler
  • Added MQTT direct connections
  • Added CoAP channels
  • Added OTA features
  • Upgraded the build system
The open-source release of the first device-side C SDK that officially supports the East China 2 sites