Regional inspection platforms (like WhisperReporter, H&S, or custom carrier portals) embed your sketcher in 10 lines of JS. They pass their sketch JSON from their own database into the iframe and listen for SKETCH_SAVED to write the calculated areas back to their own database:

<iframe id="sketchFrame" src="https://app.planimble.com/embed?apiKey=pk_live_991" class="w-full h-[650px]"></iframe>

<script>
  const frame = document.getElementById('sketchFrame');

  // 1. WRITE values from Partner's own DB into Planimble when iframe loads:
  frame.onload = () => {
    frame.contentWindow.postMessage({
      type: 'PLANIMBLE_LOAD',
      externalInspectionId: 'CLAIM-90421',
      subject: '742 Evergreen Terrace',
      areas: existingAreasFromPartnerDatabase // or [] for new sketch
    }, '*');
  };

  // 2. READ calculated square footage & vector JSON back into Partner's DB on Save:
  window.addEventListener('message', async (event) => {
    if (event.data?.type === 'PLANIMBLE_SAVED') {
      const { externalInspectionId, totals, areas, vectorJson, pngDataUrl } = event.data.payload;
      await fetch('/partner-internal-api/save-inspection-sketch', {
        method: 'POST',
        body: JSON.stringify({ externalInspectionId, glaSqFt: totals.glaSqFt, areas, vectorJson, pngDataUrl })
      });
    }
  });
</script>

For enterprise insurance platforms that want server-side synchronization: their server calls POST /api/v1/sessions with their inspection ID and webhook URL, redirects the inspector to the returned editUrl, and your ASP.NET Core backend fires a signed HMAC-SHA256 webhook back to their server whenever the sketch is created or QA-approved.