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Creating an Server in Flow-Wing

· 2 min read
Kushagra Rathore
Kushagra Rathore
Software Engineer

Get something running in a few minutes​

  1. Install a Flow-Wing SDK (see the docs: Getting Started → Installation) so you have flowwing or FlowWing and the standard modules on disk.
  2. Put the program below in main.fg. It listens on a port, waits for one HTTP request, and sends "Hello". Vortex is the HTTP stack; Err is for **listen failures.
  3. Compile and run the executable (AOT) or use JIT if you have flowwing-jit (see Flow-Wing CLI). Then curl or open the URL in a browser while the process is up.

Minimal example (one request—add a loop around accept() for a real service):

bring vortex
bring Err

fun fg_main() -> nthg {
var app: vortex::Server = new vortex::Server()
var err: Err::Result = app.listen(8080)
if Err::isErr(err) {
  println(err.getMessage())
  return:
}
var req: vortex::Request, res: vortex::Response = app.accept()
res.status(200).send("Hello")
}
fg_main()

Build (typical AOT name on PATH):

flowwing main.fg -O3

bring vortex is usually enough; you rarely need extra “server” link flags on top of a normal app. The full guide in the main docs (routing, JSON, streaming, error handling) is HTTP server (Vortex) under Creating a server in the sidebar—read that next.

  • HTTP server (Vortex) — Request / Response API, paths, and production-minded notes.
  • Err module and Flow-Wing CLI for flags and result handling.

Optional video​

For repo readers: Vortex in tests​

If you have the Flow-Wing repository, extra Vortex samples and router-style programs live under tests/fixtures/LatestTests/ServerTests/ (for example vortex_router.fg and mission_control_server/). They are regression and demo .fg files, not a separate product—use them after you are comfortable with the minimal example above.