[7] Deno explicitly takes on the role of both runtime and package manager within a single executable, rather than requiring a separate package-management program.

[10] He eventually presented the prototype of Deno, aiming to achieve system call bindings through message passing with serialization tools such as Protocol Buffers, and to provide command line flags for access control.

Deno was initially written in Go and used Protocol Buffers for serialization between privileged (Go, with system call access) and unprivileged (V8) sides.

[5] Similar to Node.js, Deno emphasizes event-driven architecture, providing a set of non-blocking core I/O utilities, along with their blocking versions.

They both have internal event loops and provide command-line interfaces for running scripts and a wide range of system utilities.

An implementation of the Unix cat program: [1] A simple Web server: [2]Deno automatically downloads and caches the remote standard library files when the script is run, and then compiles the code.

Similarly, it can run a standard library script (such as a file server) directly without explicitly downloading, by providing the URL as the input filename (-A turns on all permissions):