Sending logs

SDKs send logs to Hypertune Edge in the background. This allows you to:

  • See how often different parts of your flag logic are called, e.g. to see how often different targeting rules are evaluated and passed in realtime

  • Log events and exposures for your A/B tests and machine learning loops

  • See any SDK errors from the Hypertune UI

Manually flush logs

You can manually trigger and wait for logs to be flushed with hypertune.flushLogs():

import { NextFetchEvent, NextRequest } from "next/server";
import hypertune from "./lib/hypertune";

export async function middleware(
  req: NextRequest,
  context: NextFetchEvent
): Promise<void> {
  await hypertune.initIfNeeded();

  const rootNode = hypertune.root({
    args: {
      context: {
        user: { id: "test", name: "Test", email: "" },
  const exampleFlag = rootNode.exampleFlag({ fallback: false });
  console.log("Edge Middleware flag:", exampleFlag);


This is particularly useful in serverless environments, e.g. Vercel deployments, where background SDK tasks like fetching updates aren't guaranteed to execute.

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