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REx Types

The REx family models responses from APNIC's REx (Resource EXplorer) cross-RIR registry API at api.rex.apnic.net. REx aggregates delegated resource data across all RIRs (and NIRs where applicable), exposing per-resource, per-holder, per-source-network and aggregate-count views through a small REST surface.

All types live in models.go and carry JSON tags matching the REx wire format.

Class Diagram

classDiagram
    class RExResource {
        +string Resource
        +string Type
        +string OpaqueID
        +string HolderName
        +string RIR
        +string NIR
        +string DelegationDate
        +string TransferDate
        +string CC
    }

    class RExResourcesResult {
        +[]RExResource Items
    }

    class RExHolder {
        +string OpaqueID
        +string Registry
        +string NIR
        +string HolderName
        +[]string ASNs
        +int ASNsCount
        +[]string IPv4
        +float64 IPv4_24Count
        +[]string IPv6
        +float64 IPv6_48Count
    }

    class RExUserNetwork {
        +string IP
        +string Prefix
        +int64 ASN
        +string Economy
    }

    class RExHoldersCount {
        +int64 Count
    }

    RExResourcesResult --> RExResource

RExResource — /v1/resources

A single delegated resource record (one prefix or ASN), attributed to its holder via OpaqueID and tagged with the responsible RIR (and NIR where one applies). Type is one of "ipv4", "ipv6", "asn".

Field JSON key Description
Resource resource The prefix or ASN itself.
Type type "ipv4", "ipv6", or "asn".
OpaqueID opaqueId Stable identifier of the holder organization; joinable against the extended delegated stats and RExHolder.OpaqueID.
HolderName holderName Human-readable holder name.
RIR rir Responsible Regional Internet Registry (apnic, arin, …).
NIR nir National Internet Registry, when one applies (e.g. jpirr, idnic). Empty for direct RIR delegations.
DelegationDate delegationDate Original delegation date (string, as returned by REx).
TransferDate transferDate Most recent transfer date, if any.
CC cc Economy (ISO country) code.

RExResourcesResult — wrapper

REx's /v1/resources returns a bounded recent window of delegated resources, newest-first — not the full history. For aggregate scale across all holders use FetchRExHoldersUniqueCount (→ RExHoldersCount).

Field JSON key Description
Items items Slice of RExResource.

RExHolder — /v1/holder

The aggregated per-holder view. Given a holder's OpaqueID and the responsible RIR, REx returns every ASN and prefix attributed to that holder along with derived size metrics.

Field JSON key Description
OpaqueID opaqueId Holder identifier; matches the input.
Registry registry RIR (apnic, …).
NIR nir NIR if applicable.
HolderName holderName Human-readable holder name.
ASNs / ASNsCount asns / asnsCount All ASNs held by the holder, plus the count.
IPv4 / IPv4_24Count ipv4 / ipv4_24Count All IPv4 prefixes, plus the holder's IPv4 space expressed in /24 units.
IPv6 / IPv6_48Count ipv6 / ipv6_48Count All IPv6 prefixes, plus the holder's IPv6 space expressed in /48 units.

IPv4_24Count and IPv6_48Count are the standard "size" metrics used to compare holders across registries; they are float64 because they are summed across multiple prefixes.

RExUserNetwork — /v1/user-network

The "which network am I in?" endpoint. REx geo-locates the caller's source IP and reports the covering prefix, its origin ASN and the economy the network is registered in. It is the cross-RIR analogue of a local RDAP/whois lookup.

Field JSON key Description
IP ip The source IP REx saw (after any proxy headers it trusts).
Prefix prefix The covering delegated prefix.
ASN asn Origin ASN as an integer (0 if unknown).
Economy economy ISO economy code the network is registered in.

RExHoldersCount — /v1/holders/unique-count

The total number of distinct resource-holder organisations across all RIRs. Use this for aggregate scale rather than summing RExResourcesResult.Items (which is a bounded recent window).

Field JSON key Description
Count count Unique holder count across all RIRs.

Endpoint → type map

flowchart LR
    subgraph REx["api.rex.apnic.net"]
        E1["GET /v1/resources"]
        E2["GET /v1/holder/:opaqueId/:rir"]
        E3["GET /v1/user-network"]
        E4["GET /v1/holders/unique-count"]
    end

    E1 -->|FetchRExResources| RXRR["RExResourcesResult"]
    RXRR --> RXR["RExResource"]
    E2 -->|FetchRExHolder| RXH["RExHolder"]
    E3 -->|FetchRExUserNetwork| RXUN["RExUserNetwork"]
    E4 -->|FetchRExHoldersUniqueCount| RXC["RExHoldersCount"]