Facebook Marketplace Webhook Alerts for New Listings

If you want Facebook Marketplace listing alerts inside your own software, the useful workflow has two separate parts. A Classifindr search checks supported public Marketplace results for the item you described. A webhook channel sends the matching listing data to an HTTPS endpoint you control.

The webhook does not come directly from Facebook, and Classifindr does not claim an official Facebook integration. It is Classifindr’s signed delivery method for the matches found by your search.

How to set up a Facebook Marketplace webhook alert

1. Create a Facebook Marketplace search in Classifindr.
2. Choose the item keywords, picked locality, price range, category, condition, and check speed that fit the buying job.
3. Add include terms, exclude terms, or AI relevance filtering when broad seller wording creates noise.
4. In the desktop web portal, create a webhook endpoint with a public HTTPS URL.
5. Save the whsec_ signing secret when it is shown. It cannot be retrieved later.
6. Verify the endpoint with the signed test event.
7. Assign the active webhook channel to the Facebook Marketplace search.

Classifindr can check the search every 1, 10, or 60 minutes. After a check finds a new match, the notification worker prepares the event and attempts delivery. End-to-end timing still depends on marketplace availability, when the listing appears relative to the next check, filtering, and the receiver.

What the Facebook listing webhook contains

The alert.listing.matched.v1 event includes the saved search, the match, and bounded public listing fields that help a receiver decide what to do next. Useful fields include:

• a stable event identifier
• the search and match identifiers
• platform and search name
• listing title, description, price, currency, and source URL when available
• broad search locality fields when known
• broad listing location text when Facebook supplies it
• match reasons and the change type
• an optional Classifindr-cached thumbnail URL

The payload does not include Facebook credentials, seller account identity fields, webhook secrets, request signatures, coordinates, raw provider responses, or internal scoring and cost data. Facebook may omit listing location. For a Facebook-only search, the search radius value is null because Facebook controls the approximate default area for the public results returned around the selected locality.

Open the original Facebook Marketplace listing before messaging a seller or making a buying decision. A webhook match is a lead, not a verification of ownership, condition, availability, price accuracy, or seller identity.

Use the event type to route the next action

Classifindr currently sends two alert event types:

Event	What changed	Useful receiver action
alert.listing.matched.v1	A check found a new listing that passed the search rules	Add it to a buying queue, inventory candidate table, or review dashboard
alert.listing.price_decreased.v1	A previously tracked listing has a lower price	Recalculate margin, raise its priority, or ask a buyer to review it again

Do not build one giant automation for every search. Route a rare camera model differently from a broad furniture search. The webhook event contains search context so your receiver can choose a queue, owner, priority, or downstream action without guessing from the title alone.

Verify every signed delivery

Your endpoint should read the raw UTF-8 request body and verify the Standard Webhooks headers before parsing JSON. Use Webhook-Id, Webhook-Timestamp, and each v1 value in Webhook-Signature with the one-time secret. Reject requests outside a five-minute timestamp window and keep a processed-event record keyed by Webhook-Id.

Return a 2xx response quickly after validation, then do slower work asynchronously. Webhook delivery is at least once and unordered, so a retry can deliver an event you have already seen and a later event can arrive first. The marketplace webhook receiver guide explains the complete acceptance path and links to maintained Node.js and Python verification examples.

Connect Facebook Marketplace alerts to the tools you use

A webhook is useful whenever a listing needs to become structured work rather than another personal notification. Common patterns include:

• add a candidate to an internal buying dashboard
• create a review item for a sourcing partner
• attach a new listing to an inventory or margin-tracking record
• route high-value searches to an on-call buyer
• keep a private research dataset of the alert fields your account received
• start an automation in a webhook-capable workflow tool

If a third-party automation service receives the event, confirm that it can preserve the raw request body for signature verification and that you are allowed to send the listing data to it. Never paste the signing secret into a public workflow, log, ticket, or client-side script.

Troubleshoot a Facebook Marketplace webhook that is not firing

Work through the pipeline in order:

1. Check the search. Confirm that it is active, healthy, and finding public Facebook Marketplace listings for the selected locality.
2. Check filtering. Review filtered listings and match reasons. A listing can be found but correctly withheld by title rules or relevance filtering.
3. Check assignment. Confirm that the active webhook channel is assigned to this search, or is configured as a default channel when the search has no explicit assignments.
4. Send a test. Use the desktop portal to send a recorded test event. A test checks the receiver independently of marketplace search activity.
5. Inspect delivery history. Look for the safe failure reason, response class, and retry state. Delivery attempts and bounded payload snapshots remain visible for 30 days.
6. Fix the receiver. Validate HTTPS reachability, raw-body verification, timestamp handling, response time, and deduplication before redelivering.

A successful test does not prove that a particular Facebook search will find a listing. It proves that a signed Classifindr test request reached the endpoint and received a 2xx response.

Keep phone alerts and webhooks focused

You do not have to choose one channel for the entire account. Send urgent Facebook Marketplace searches to mobile push and a webhook when both a person and a system need the match. Send quieter research searches only to the dashboard or webhook. Use separate search assignments so a background watch does not create the same interruption as an item you are ready to buy today.

Start with one narrow Facebook Marketplace search and one receiver. Test the signed request, review a real delivery, and make the downstream action idempotent before connecting the rest of your searches.