Vix.cpp

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Vix.cpp Examples Guide (Beginner Friendly) ​

Welcome to Vix.cpp.

This guide is designed for developers coming from:

  • Python (FastAPI, Flask)
  • Node.js (Express)
  • Simple HTTP servers in other languages

The goal is to show you how to think in Vix.

Vix is:

  • Explicit
  • Predictable
  • No magic
  • No hidden runtime behavior
  • C++ performance with modern syntax
  1. Minimal Server (Hello World)

In Node.js (Express):

js
    app.get("/", (req, res) => {
        res.json({ message: "Hello" });
    });

In Vix:

cpp
#include <vix.hpp>

using namespace vix;

int main()
{
    App app;

    app.get("/", [](Request&, Response& res) {
        res.json({"message", "Hello Vix"});
    });

    app.run(8080);
}

Run it:

bash
    vix run main.cpp

Open:

bash
    http://localhost:8080
  1. Returning JSON Automatically

In Vix you can either:

  • Use res.json(...)
  • Or return JSON directly

Example:

cpp
app.get("/auto", [](Request&, Response&) {
    return vix::json::o(
        "framework", "vix",
        "language", "c++",
        "fast", true
    );
});

If you return a value, Vix auto-sends it.

  1. Path Parameters (Like Express :id)

Node.js:

app.get("/users/:id", ...)

Vix:

cpp
app.get("/users/{id}", [](Request& req, Response& res) {
    std::string id = req.param("id", "0");

    res.json({
        "id", id,
        "name", "User#" + id
    });
});

Test:

bash
    http://localhost:8080/users/42
  1. Query Parameters

Example:

/search?q=vix&page=2
cpp
app.get("/search", [](Request& req, Response& res) {

    std::string q = req.query_value("q", "");
    std::string pageStr = req.query_value("page", "1");

    res.json({
        "query", q,
        "page", pageStr
    });
});
  1. Status Codes
cpp
app.get("/created", [](Request&, Response& res) {
    res.status(201).json({
        "status", 201,
        "message", "Created"
    });
});
  1. Reading Headers
cpp
app.get("/headers", [](Request& req, Response& res) {

    std::string ua = req.header("User-Agent");

    res.json({
        "user_agent", ua
    });
});
  1. Reading JSON Body

Even though GET is used here for demo purposes, normally POST is used.

cpp
app.post("/echo", [](Request& req, Response& res) {

    auto j = req.json();

    if (!j.is_object()) {
        res.status(400).json({"error", "Invalid JSON"});
        return;
    }

    res.json({
        "received", j
    });
});
  1. Returning Text
cpp
app.get("/text", [](Request&, Response&) {
    return "Plain text response";
});
  1. Organizing Routes

Instead of writing everything in main(), do this:

cpp
void register_routes(App& app)
{
    app.get("/", [](Request&, Response& res){
        res.json({"ok", true});
    });

    app.get("/health", [](Request&, Response& res){
        res.json({"status", "healthy"});
    });
}

int main()
{
    App app;
    register_routes(app);
    app.run(8080);
}

Keep main() clean.

  1. Disabling Auto Docs

By default Vix can generate OpenAPI docs.

To disable:

bash
    vix run api.cpp --no-docs

Mental Model for Python / Node Developers ​

In Python or Node:

  • The runtime hides many details.
  • Middleware stacks are dynamic.
  • Garbage collection is automatic.

In Vix:

  • Everything is explicit.
  • No garbage collector.
  • No hidden async magic.
  • You control memory and execution.

This gives:

  • Lower latency
  • Higher predictability
  • Better performance under load

Where to Go Next ​

After this guide:

  • Explore Session and ThreadPool for advanced execution
  • Enable OpenAPI and test /docs
  • Add your own real API routes
  • Connect to a database
  • Deploy to production

Vix is simple at the surface. Powerful underneath.

Keep building.