Build Varmo into your processes.

import { createHmac, timingSafeEqual } from "node:crypto";

// rawBody: der unveränderte Inhalt der Anfrage (Text), nicht neu serialisiert.
export function verifyVarmoSignature(secret, header, rawBody, toleranceSeconds = 300) {
  const parts = Object.fromEntries(
    String(header ?? "").split(",").map((p) => p.trim().split("=")),
  );
  const timestamp = Number(parts.t);
  if (!Number.isInteger(timestamp) ||
      Math.abs(Date.now() / 1000 - timestamp) > toleranceSeconds) {
    return false;
  }
  const expected = createHmac("sha256", secret)
    .update(`${timestamp}.${rawBody}`)
    .digest("hex");
  const given = String(parts.v1 ?? "");
  return given.length === expected.length &&
    timingSafeEqual(Buffer.from(given), Buffer.from(expected));
}

import hashlib
import hmac
import time


def verify_varmo_signature(secret: str, header: str, raw_body: bytes, tolerance: int = 300) -> bool:
    parts = dict(p.strip().split("=", 1) for p in (header or "").split(",") if "=" in p)
    try:
        timestamp = int(parts.get("t", ""))
    except ValueError:
        return False
    if abs(time.time() - timestamp) > tolerance:
        return False
    expected = hmac.new(secret.encode(), f"{timestamp}.".encode() + raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, parts.get("v1", ""))

function Test-VarmoSignature {
  param([string]$Secret, [string]$Header, [string]$RawBody, [int]$Tolerance = 300)
  $parts = @{}
  foreach ($p in ($Header -split ',')) {
    $kv = $p.Trim() -split '=', 2
    if ($kv.Count -eq 2) { $parts[$kv[0]] = $kv[1] }
  }
  $t = 0L
  if (-not [long]::TryParse([string]$parts['t'], [ref]$t)) { return $false }
  $now = [DateTimeOffset]::UtcNow.ToUnixTimeSeconds()
  if ([math]::Abs($now - $t) -gt $Tolerance) { return $false }
  $hmac = New-Object System.Security.Cryptography.HMACSHA256 (,[Text.Encoding]::UTF8.GetBytes($Secret))
  $hash = $hmac.ComputeHash([Text.Encoding]::UTF8.GetBytes("$t.$RawBody"))
  $expected = -join ($hash | ForEach-Object { $_.ToString('x2') })
  return $expected -ceq [string]$parts['v1']
}