# ExpressLink Documentation

ExpressLink hardware modules are pre-programmed to connect to AWS IoT services and are pre-loaded with security credentials. They allow original equipment manufacturers (OEMs) to connect many different products to the cloud, send data and commands using simple commands, and use AWS services to address their data storage, analytics, and machine learning (ML) needs.

- [AWS IoT ExpressLink Programmer's Guide](/iot-expresslink/latest/programmersguide/elpg.html): Defines the application programming interface (API) that all connectivity modules compliant with AWS IoT ExpressLink are required to implement in order to connect host processors to the AWS cloud.
- [AWS IoT ExpressLink Getting Started Guide](/iot-expresslink/latest/gettingstartedguide/elgsg.html): Walks through how to connect an AWS IoT ExpressLink Evaluation Kit to the cloud to send and receive data directly with your AWS account.
- [AWS IoT ExpressLink Onboarding-by-Claim Customer/OEM Guide](/iot-expresslink/latest/oemonboardingguide/oemog.html): Walks through how to use an onboarding-by-claim mechanism created to leverage an AWS IoT ExpressLink module's unique security and connectivity capabilities.

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