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Endpoint URL Requirements

HookBridge validates every endpoint URL when you create or update an endpoint. These rules apply equally to outbound endpoints (where HookBridge delivers webhooks) and inbound forwarding URLs (where HookBridge forwards received webhooks).

Understanding the requirements up front avoids validation errors during setup.

All endpoint URLs must use HTTPS. HTTP URLs are rejected.

https://your-app.example/webhooks ✓
http://your-app.example/webhooks ✗
  • Minimum: 12 characters
  • Maximum: 2,048 characters

The endpoint’s domain must resolve via DNS. If the domain cannot be resolved, the endpoint is rejected with ENDPOINT_UNREACHABLE.

Endpoint URLs must not target private, internal, or reserved IP addresses. This includes:

  • Loopback addresses (127.0.0.0/8, ::1, localhost)
  • Private network ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)
  • Link-local addresses (169.254.0.0/16, fe80::/10)
  • IPv6 unique local addresses (fc00::/7)
  • Multicast addresses (224.0.0.0/4)
  • Unspecified addresses (0.0.0.0, ::)

Requests to these addresses are rejected with ENDPOINT_BLOCKED.

Endpoint URLs must not point back to HookBridge domains. This is rejected with a validation error.

CodeMeaning
INVALID_ENDPOINTURL is not HTTPS, is too short/long, or is otherwise malformed.
ENDPOINT_UNREACHABLEDomain could not be resolved via DNS.
ENDPOINT_BLOCKEDURL resolves to a private or internal address.
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