oak

Oak works seamlessly across Deno, Node.js, Bun, and Cloudflare Workers, as highlighted in the README's multi-runtime support, allowing developers to write once and deploy anywhere with minimal changes.

It uses an async middleware stack similar to Koa, enabling fine-grained control over request/response flow, demonstrated in the logging and timing examples where middleware can await next() and modify headers.

Includes a router with parameter parsing, nested routing, and path-to-regexp support, making it easy to define RESTful endpoints without external dependencies, as shown in the book API example.

Aligns with Fetch API standards for body parsing (e.g., .json(), .formData()) and uses Request/Response objects, reducing boilerplate and improving interoperability with web standards.

Offers a send() function with ETag and caching headers for serving static assets, automatically handling conditional requests to improve performance, as detailed in the static content section.