🔗Getting started

🔗Requirements

Nim >= 2.2.0
nimble (comes with Nim)

Dependencies are resolved automatically by nimble:

nimsimd >= 1.3.2
mimedb >= 0.1.1
openparser >= 0.1.8
multipart >= 0.1.4
checksums >= 0.2.2

🔗Installation

nimble install powpow

For a local checkout, from the repository root:

nimble install -Y

🔗Your first HTTP server

import powpow

let server = newHttpServer()          # creates its own loop

proc handler(req: HttpRequest, res: HttpResponse) {.gcsafe.} =
  if req.getPath() == "/":
    res.status(Http200)
       .header("Content-Type", "text/html; charset=utf-8")
       .send("<h1>Hello from powpow!</h1>")
  else:
    res.sendError(Http404)

server.start(handler, Port(9000))

Compile and run:

nim c -r -d:release myserver.nim
curl http://localhost:9000/

That's the whole library surface in one handler: req gives you the parsed request, res is a fluent response builder.

🔗Your first WebSocket server

import powpow

let wss = newWsServer()
wss.onMessage(proc(ws: WsConnection, kind: WsFrameKind, data: openArray[byte]) =
  ws.sendText("echo: " & cast[string](data)))

wss.start()
wss.listen("0.0.0.0", 9001)

nim c -r -d:release wsdemo.nim
websocat ws://localhost:9001

🔗Running the examples

Every example in examples/ is runnable:

nim c -r examples/httpserver.nim          # HTTP server on :9000
nim c -r --threads:on examples/httpserver_threads.nim   # multi-threaded on :9000

See the examples index for the full list, ports and test commands.

🔗Build flags and notes

--threads:on — required for the multi-threaded server (concurrency) and the thread-safety tests. The core event loop itself is single-threaded and does not require it.
-d:release — always use release for benchmarking or real workloads.
--features:io_uring / -d:powpowIoUring — Linux only: switch the I/O backend to io_uring (submission-based). The same code runs unchanged; see the io_uring guide for the zero-copy options and configuration.
-d:powpowEnableMetrics — compile-time opt-in for event-loop metrics (roadmap item; not yet implemented).
Windows — supported via IOCP, but TLS is not available on Windows and the WebSocket/file-watching feature set is less complete.
Unix domain sockets — listenUnix/connectUnix are POSIX-only.

🔗Running the tests

nimble test            # the standard suite
nimble testThreads     # thread-safety smoke tests (--threads:on)
nimble testSmuggler    # parser fuzzing with the smuggler package (if installed)

See testing for the full test-suite map.

🔗A note on routing

powpow deliberately ships no router. Routing is up to you — simple if/case on getPath(), or a framework such as Supranim built on top of powpow's OnRequestCallback. See the HTTP server guide for the routing idioms used by the examples.

🔗Where to go next

Overview — architecture and the full feature matrix
Event loop — the foundation everything sits on
HTTP server — routing, responses, config
Examples index — 19 runnable programs

Getting Started

Core

Networking

HTTP

Other Protocols

Concurrency