Next.js spam filter.

// app/api/contact/route.ts
import { NextResponse } from "next/server";

export async function POST(req: Request) {
  const { email, message } = await req.json();
  if (!email || !message) {
    return NextResponse.json({ error: "email and message required" }, { status: 400 });
  }

  let probability = 0;
  let ceiling = null;
  try {
    const resp = await fetch("https://api.siftfy.io/v1/predict", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        "X-API-Key": process.env.SIFTFY_KEY!,
      },
      body: JSON.stringify({ text: message }),
      signal: AbortSignal.timeout(2000),
    });
    if (resp.ok) {
      const data = await resp.json();
      probability = data.spam_probability;
      ceiling = data.max_confidence ?? null;
    }
  } catch {
    probability = 0;
  }

  // Drop only ABOVE the ceiling the response reports. At the ceiling the score
  // is censored, so a fixed constant never fires on the model's own opinion.
  if (ceiling !== null && probability > ceiling) return NextResponse.json({ ok: true });
  if (probability >= 0.50) await queueForReview({ email, message, probability });
  else await sendLead({ email, message });
  return NextResponse.json({ ok: true });
}