This is what I am best know for -
With my past companies, the applications had regular issues, public APIs are vulnerable, wasn't fault tolerant, had multiple downtimes in the day.
I have worked in stages on the applications, made them stable, fault tolerant.
Added security measures. Improved api response time.
Added processes for better error tracking and resolution.
Added Typescript to projects. Set processes for documentation, rules for contributing to code.
Setup CI/CD pipelines with git hooks, Github workflow, Terraform.
Added workflows and made the team follow agile process of development.
Identified and Automated manual work for many teams.