Glean Webhooks & Events

Overview

Glean uses an event-driven indexing model where source system webhooks trigger incremental updates to the Glean Indexing API. Instead of emitting its own webhooks, Glean receives document changes from platforms like GitHub, Confluence, and Notion. You can also monitor internal Glean events such as document indexing completion, permission changes, connector sync status, and search anomalies through the admin API.

Webhook Registration

// Register a source system webhook that pushes to Glean Indexing API
const response = await fetch("https://yourapp.com/admin/webhooks", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    url: "https://yourapp.com/webhooks/glean-indexer",
    events: ["document.indexed", "permission.changed", "connector.synced", "search.anomaly"],
    secret: process.env.GLEAN_WEBHOOK_SECRET,
  }),
});

Signature Verification

import crypto from "crypto";
import { Request, Response, NextFunction } from "express";

function verifyGleanSignature(req: Request, res: Response, next: NextFunction) {
  const signature = req.headers["x-glean-signature"] as string;
  const expected = crypto.createHmac("sha256", process.env.GLEAN_WEBHOOK_SECRET!)
    .update(req.body).digest("hex");
  if (!crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))) {
    return res.status(401).json({ error: "Invalid signature" });
  }
  next();
}

Event Handler

import express from "express";
const app = express();

app.post("/webhooks/glean-indexer", express.raw({ type: "application/json" }), verifyGleanSignature, (req, res) => {
  const event = JSON.parse(req.body.toString());
  res.status(200).json({ received: true });

  switch (event.type) {
    case "document.indexed":
      confirmIndexStatus(event.data.datasource, event.data.doc_id); break;
    case "permission.changed":
      reindexPermissions(event.data.datasource, event.data.object_id); break;
    case "connector.synced":
      logSyncMetrics(event.data.connector_name, event.data.docs_processed); break;
    case "search.anomaly":
      alertOps(event.data.query_pattern, event.data.anomaly_type); break;
  }
});

Event Types

Event	Payload Fields	Use Case
document.indexed	datasource, doc_id, index_time_ms	Confirm content is searchable
permission.changed	datasource, object_id, new_acl	Re-sync access controls
connector.synced	connector_name, docs_processed, errors	Monitor connector health
search.anomaly	query_pattern, anomaly_type, severity	Detect unusual search behavior
document.deleted	datasource, doc_id, deleted_by	Audit content removal

Retry & Idempotency

const processed = new Set<string>();

async function handleIdempotent(event: { id: string; type: string; data: any }) {
  if (processed.has(event.id)) return;
  await routeEvent(event);
  processed.add(event.id);
  if (processed.size > 10_000) {
    const entries = Array.from(processed);
    entries.slice(0, entries.length - 10_000).forEach((id) => processed.delete(id));
  }
}

Error Handling

Issue	Cause	Fix
Index rejected	Document exceeds size limit	Chunk large documents before indexing
Permission denied	Stale OAuth token for connector	Refresh connector credentials in admin
Duplicate documents	Source sends create + update rapidly	Deduplicate by doc_id before indexing
Connector timeout	Source API rate limited	Implement exponential backoff in connector

Prerequisites

• A secret-manager webhook secret, an approved event origin allowlist, a replay-window policy, and an opaque event ledger.
• A sandbox receiver with fictional events and a tested disable/rollback control for the consumer.
• Data-owner approval for every event type that can alter an index, permission mapping, or retention state.

Instructions

1. Authenticate the source before parsing, validate timestamp and event ID, and reject unknown origins, stale deliveries, and malformed payloads.
2. Store only a bounded, redacted event envelope and use event ID plus target revision as the idempotency key.
3. Validate source ACL and destination before enqueueing work; quarantine uncertainty rather than creating or changing indexed content.
4. Process one canary source first, observe synthetic allow/deny outcomes and queue health, then promote or disable the consumer.
5. Retry transient failures within a fixed budget and route exhausted events to a reviewed dead-letter path without replaying non-idempotent writes.

Output

Return an event receipt with event type, opaque event ID, signature/timestamp result, target datasource, idempotency outcome, queue state, canary result, and rollback reference. Exclude payload content and signatures.

Examples

type=document.updated; event=evt-opaque-9; signature=pass; replay=absent; source=sandbox-guides; enqueue=once; allow=pass; rollback=consumer-disabled proves the event boundary.

Resources

• Glean Indexing API

Next Steps

See glean-security-basics.