In the past, I’ve worked with the following:
JavaScript (Express/Node, Svelte/Sveltekit), HTML/CSS (of course), PHP, Python (Flask), MySQL, Postgres, MongoDB, Supabase.
If you have any requests relating to specific languages/technologies, please feel free to reach out and ask. That being said, even though I do build tools, websites (like this one) and write/edit code on occasion, please note that I am not a web developer by profession. It can, therefore, be worth working with a developer to implement major changes to large websites/code-bases as this is not my area of expertise. I’m an SEO with programming skills, not a developer with SEO skills. Although this may seem like a minor syntactical difference, it’s actually a major one!