Hono

Now the default for small backends on Cloudflare Workers — the per-request context and lazy environment binding keep a throwaway tool down to a single file, so the cost of shipping one is low enough that it stops being a decision. It also pairs well with the stateless mode of Model Context Protocol v2, where a server holds no session state and a new capability can be handed to an agent as just another Worker.

Hono is web framework design for serverless applications which use "Context" in each request that can support lazy initialized environment variables.