> ## Documentation Index
> Fetch the complete documentation index at: https://docs.interchange.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Public callback URL requirements

> Requirements for partner-agent endpoints and buyer task callbacks

Partner-agent endpoints and buyer task callback URLs must be directly reachable
public HTTPS endpoints. If your URL already meets those requirements, no action
is needed.

## Where this applies

* **Sellers:** the endpoint URL when you register or update a partner agent.
* **Buyers:** the callback URL you provide for asynchronous storefront task
  results.

## Requirements

Your URL must:

1. Use `https://`.
2. Resolve only to public IP addresses.
3. Accept the webhook directly; redirects are not followed.

URLs that point to `localhost`, private or link-local networks, cloud metadata
addresses, multicast ranges, or encoded numeric IP forms are rejected. A
hostname that looks public is also rejected when DNS resolves it to any
non-public address.

## What you will see

When a seller creates or updates a partner agent with an incompatible endpoint,
the request returns a validation error. For buyer task callbacks, Interchange
checks the destination again immediately before delivery; an unsafe or
unresolvable destination is not called.

Use a stable public DNS name or public IP address, terminate TLS at that
destination, and configure the final callback URL rather than a redirecting
link. Test the exact URL from a network outside your private environment before
registering it.