Ping post is the exchange that lets a buyer's own system decide, in real time, whether to accept a specific lead or call before anything is delivered or billed. It shows up across pay-per-lead and pay-per-call buying in different forms, and Callmart's wholesale buyers can opt into a version of it for inbound calls, called buyer preacceptance ping.
The basic ping post exchange
A ping is a request sent to a buyer's system describing an opportunity, a lead record in lead buying, or in Callmart's case a proposed call. The buyer's system checks whatever it wants to check, budget remaining, existing customer records, current staffing, and returns a decision. If the buyer accepts, the marketplace posts the full record or connects the call. If the buyer declines, the opportunity moves on rather than sitting and waiting.
The name describes the two steps in order. The ping carries a limited set of details, enough to decide, not the full record. The post, if the buyer accepts, delivers the real thing: a lead's contact information, or a live connected call.
Why ping post exists
Without a pre-acceptance step, a marketplace either sends everything to everyone who is switched on, or a person has to review each opportunity before it moves, which is far too slow for a call that is happening right now. Ping post gives a buyer's own system a narrow window to apply its own logic before committing.
- A buyer at their daily spending limit can decline automatically instead of overspending.
- A buyer who already has that customer on file can decline a likely duplicate.
- A buyer with every agent already on a call can decline rather than let a call ring out unanswered.
Ping post for leads versus ping post for calls
In lead buying, a ping usually carries a small set of fields, something like a state and a general interest, and the buyer's system scores it before the full contact record posts. Call buying runs on a tighter clock. There is no separate record to withhold, since the call itself is the live event: either the buyer's system accepts the opportunity to be connected, or it does not, inside a window measured in seconds rather than the longer window a lead exchange can sometimes tolerate.
How Callmart's buyer preacceptance ping fits in
Callmart's version of this is buyer preacceptance ping, available to wholesale buyers. A buyer supplies an HTTPS endpoint and an API key inside Buyer ping settings, under Delivery controls, in their workspace. The endpoint must be publicly reachable HTTPS on port 443; private or internal hostnames are rejected, and the API key is stored encrypted at rest with AES-256-GCM.
| Field | What it carries |
|---|---|
| request_id | The unique identifier for that specific call opportunity |
| offer_id | An identifier for the offer or campaign the call belongs to |
| caller_id | The calling consumer's number, in E.164 format |
| state | A two letter US state code |
| expires_at | When the offer stops being valid |
| is_test | Marks the request as test traffic, not a live call |
For every proposed call, Callmart sends an HTTP POST to that endpoint with an Authorization bearer header carrying the buyer's own API key, and a JSON body carrying the fields above.
What a buyer's endpoint needs to do
To accept the call, the endpoint returns JSON with accept: true and the exact request_id it was sent. Anything else, accept: false, a mismatched request_id, invalid JSON, an unreachable host, or a timeout, denies the call. The HTTP request itself times out at 3 seconds, the total buyer decision deadline is 4 seconds, and the whole exchange sits inside a 30 second provisional reservation. Ping is per buyer and always on once enabled. A buyer with no configuration enabled is simply accepted immediately, with no ping step at all.
Practical notes for building your endpoint
- 01Respond fastBuild for the 3 second timeout as your normal case, not your worst case.
- 02Keep the endpoint warmA cold start that eats your timeout budget is indistinguishable from a down endpoint.
- 03Treat every ping as idempotentDesign your handler so receiving the same request_id twice never causes a problem.
- 04Log request_id on every decisionIt is the one identifier that ties your logs back to a specific call opportunity.
- 05Never block on a slow downstream systemIf a system you depend on is slow, return a denial rather than let the whole request time out.
- 06Test with is_test traffic firstVerify your endpoint against real formatted requests before you enable it for live calls.
Common questions
01Is ping post the same for every Callmart buyer?
No. On Callmart, ping is a per buyer setting inside Delivery controls, and it is only active for buyers who have configured and enabled an endpoint. A buyer with nothing configured is accepted immediately, with no ping step.
02What happens if my endpoint times out?
A timeout is treated as a decline. The request has a 3 second window and the full decision needs to land inside 4 seconds, so a slow endpoint denies calls it might otherwise have accepted.
03Can I test my ping endpoint before going live?
Yes. Requests can carry an is_test flag so you can build and verify your endpoint against real, correctly formatted traffic before you enable it for live calls.
04Does ping post apply to every Callmart buyer, not just wholesale?
Buyer preacceptance ping is a wholesale feature, configured per account. Other buyers use the standard availability and delivery controls in their workspace.