Injecting secrets into build or deployment processes is crucial for ensuring secure interactions between services, particularly when deploying across multiple environments. To avoid hardcoding sensitive information like API tokens into configuration files, which poses security risks, a dynamic approach is recommended. This involves generating config files on the fly and injecting secrets into CI/CD pipeline jobs. CircleCI offers a solution with its contexts feature, which securely stores secrets using Hashicorp Vault and makes them accessible as environment variables within pipeline jobs. Alternatively, third-party secret stores can be used for greater flexibility, though this requires additional scripting for integration. The choice of template rendering engine, influenced by the tools and languages in use, plays a vital role in dynamically creating config files. By leveraging CircleCI's conveniences, such as pre-built images and orbs, and caching rendered templates for efficiency, organizations can maintain secure, efficient, and scalable CI/CD pipelines.