Wrangler

wrangler dev runs a Worker on your machine with workerd, the same runtime Cloudflare uses in production, plus local copies of KV, R2 and D1. wrangler deploy uploads it, wrangler tail streams live logs, and commands such as wrangler secret put and wrangler d1 migrations apply handle secrets and database changes.

Settings live in a wrangler.jsonc or wrangler.toml file beside the code: the Worker's name, compatibility date, routes, bindings and variables. Keeping that file in Git makes deployments repeatable and easy to run from CI.