What is SOLID The SOLID is an acronym created in 2004 based on principles that Uncle Bob introduced in the 2000s to identify the best practices of software design. 💡 Disclaimer: I’m not giving a full description of the SOLID pattern because a lot of folks have done that. Digital Ocean has done that and the Uncle Bob himself has done that Although the SOLID principles may apply to any object-oriented design, they usually bring with them the Clean Code and Clean Architecture philosophies.