Retreaver setup

How it works on Retreaver

Retreaver campaign webhooks can fire on the Start trigger, as soon as the call is received and before routing. Even better: when the pinged URL returns flat JSON, Retreaver applies the root keys and values to the call as tags automatically. CallerSift's response is flat JSON, so verdict, reason, and line_type become call tags with zero mapping work, and your buyers filter on them.

Your lookup URL

Every workspace gets one lookup URL, shown on your dashboard home page. POST the caller number to it and the JSON response answers verdict: allow or block.

POSThttps://api.callersift.com/v1/your-workspace

Wire it up

1. Edit the campaign that receives the calls you want screened.
2. Scroll to the Webhooks section, click Add, and pick the Start trigger (fires as soon as the call is received).
3. Build the webhook with the Webhook Configurator: ping_method POST, ping_headers {"Content-Type":"application/json","X-Api-Key":"fck_your_key"}, and ping_data {"caller_number":"[caller_number]"}. The [caller_number] token is the caller ID in E.164, per Retreaver's tag reference.
4. Do NOT use a plain URL-with-query-parameters webhook: Retreaver pings those as GET, and the lookup API only answers POST, so nothing gets screened (and your key would ride in a logged URL).
5. On every buyer (Call Endpoint) in the campaign, add a tag filter requiring verdict = allow. A blocked caller then matches no endpoint and never connects.

Apply the verdict = allow filter to every buyer in the campaign. Any endpoint without the filter is a path a blocked caller can still leak through.

Beat the race

1. Retreaver gives webhooks a 5 second response window and can start routing before a slow webhook returns. CallerSift answers in milliseconds, but Retreaver's own fix is worth adopting anyway: add a short Greeting or Please Hold prompt so tags always land before the routing decision (their troubleshooting guide recommends exactly this).
2. Place one live call and watch the verdict land twice: as tags on the Retreaver call, and in your CallerSift lookup log with the caller number and reason.

A lookup that fails or times out answers allow: an outage on the scoring path never blocks a genuine caller.

Official Retreaver docs

1. Webhooks guide: triggers, the UI path, and the root-JSON-to-tags rule.
2. Webhook Configurator: custom methods, headers, JSON bodies, and response mapping.
3. Tag types and operators: the [caller_number] token family and buyer tag filters.
4. Troubleshooting webhooks: timing, latency, and the hold-prompt pattern.