The key programming languages for IoT development include:

C: Widely used for its efficiency and low-level hardware interaction capabilities, making it ideal for embedded systems and microcontroller programming.
C++: Builds on C by adding object-oriented features, providing a powerful tool for developing complex IoT applications.
Python: Known for its simplicity and readability, Python is excellent for quick development and prototyping of IoT applications. It also has numerous libraries for data analysis, machine learning, and connectivity.
Java: Offers platform independence with its "write once, run anywhere" capability, making it suitable for IoT devices that need to operate across different environments.
JavaScript: Essential for web-based IoT applications, enabling real-time updates and communication through various frameworks and libraries.
Rust: Gaining popularity for its safety and performance, Rust is used in IoT for developing robust and concurrent systems.
Node.js: Utilized for server-side development, it allows for the efficient handling of numerous connections, making it suitable for IoT solutions requiring real-time data processing.

Choosing the right language depends on the specific requirements of your IoT project, such as hardware constraints, performance needs, and development speed. To gain a comprehensive understanding and hands-on experience, consider enrolling in an IoT certification course.