HPD API v1.2

A free, public HTTP API for decoding raw network packets using the Wireshark/tshark engine. No authentication required.

Introduction

Hex Packet Decoder exposes a REST API at /api that accepts a raw hex packet and returns a full protocol dissection in XML (PDML), plain text, or PNG image format.

All requests are simple GET calls — no API key, for reasonable use only (100 requests maximum per hour).

Endpoint

GET https://hpd.gasmi.net/api

Parameters

Parameter	Required	Values	Description
`data`	Yes	hex string	Raw packet bytes in hex. Accepts raw hex, spaced hex, tcpdump/Wireshark dump formats. The packet must start with an Ethernet header unless `force` is set.
`format`	No	`xml` (default) `text` `file` `png`	`xml` — PDML XML, inline in the response. `text` — plain text tree (equivalent to `tshark -V`). `file` — PDML XML as a downloadable attachment. `png` — a PNG image of the hex map.
`force`	No	`ipv4` `ipv6`	Treat `data` as a raw IPv4 or IPv6 payload with no Ethernet header. HPD prepends a dummy 14-byte Ethernet header automatically.

Response: XML (PDML)

The default response wraps standard PDML output with an <hpd_info> metadata block at the top of the <pdml> element.

hpd_info fields

Field	Description
`bytes`	Normalised hex bytes that were decoded (including any prepended dummy Ethernet header)
`force_ipv4`	`True` if `force=ipv4` was used
`force_ipv6`	`True` if `force=ipv6` was used
`time_ms`	Server-side decoding time in milliseconds
`request_error`	`True` if the request itself was invalid
`packet_error`	`True` if tshark could not parse the packet
`hpd_version`	HPD version string

Example XML response

<?xml version="1.0" encoding="utf-8"?>
<pdml version="0" creator="hpd.gasmi.net" …>
  <hpd_info>
    <bytes>000000000000000000000000080045000028…</bytes>
    <force_ipv4>True</force_ipv4>
    <force_ipv6>False</force_ipv6>
    <time_ms>374</time_ms>
    <request_error>False</request_error>
    <packet_error>False</packet_error>
    <hpd_version>4.1</hpd_version>
  </hpd_info>
  <packet>
    <proto name="eth" showname="Ethernet II, Src: …" size="14" pos="0">
      <!-- field elements … -->
    </proto>
    <proto name="ip" …> … </proto>
    <proto name="udplite" …> … </proto>
  </packet>
</pdml>

Response: Text

With format=text, the response is a plain-text protocol tree identical to tshark -V output — useful for quick inspection or logging.

Frame 1: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Jul 14, 2020 01:58:36.000000000 CEST
    …
Ethernet II, Src: 00:00:00_00:00:00, Dst: 00:00:00_00:00:00
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 139.133.204.176, Dst: 139.133.204.183
    Version: 4
    Header Length: 20 bytes
    Total Length: 40
    Time to live: 64
    Protocol: UDPLite (136)
    Source: 139.133.204.176
    Destination: 139.133.204.183
Lightweight User Datagram Protocol, Src Port: 32768, Dst Port: 1234
    Source Port: 32768
    Destination Port: 1234
    Checksum: 0xf53f
Data (12 bytes)
0000  68 65 6c 6c 6f 20 77 6f 72 6c 64 0a   hello world.

Response: PNG

With format=png, the response is a PNG image of the hex map with the protocol legend — the same graphic shown on the main interface. Useful for embedding in reports or documentation.

Examples: curl

IPv4 + UDPLite payload, default XML output

curl "https://hpd.gasmi.net/api?force=ipv4&data=4500002852924000408837498B85CCB08B85CCB7800004D2000CF53F68656C6C6F20776F726C640A000000000000"

Plain text output

curl "https://hpd.gasmi.net/api?force=ipv4&data=4500002852924000408837498B85CCB08B85CCB7800004D2000CF53F68656C6C6F20776F726C640A000000000000&format=text"

Download as PDML file

curl -O -J "https://hpd.gasmi.net/api?force=ipv4&data=4500002852924000…&format=file"

Download as PNG

curl -o packet.png "https://hpd.gasmi.net/api?force=ipv4&data=4500002852924000…&format=png"

Examples: Python

Decode and walk the PDML tree

import requests, xml.etree.ElementTree as ET

hex_data = "4500002852924000408837498B85CCB08B85CCB7800004D2000CF53F68656C6C6F20776F726C640A000000000000"

r = requests.get("https://hpd.gasmi.net/api", params={
    "data":  hex_data,
    "force": "ipv4",
})

root = ET.fromstring(r.text)

# Print top-level protocol names
for proto in root.find("packet").iter("proto"):
    print(proto.get("name"), "→", proto.get("showname"))

Check for errors

info = root.find("hpd_info")
if info.findtext("request_error") == "True":
    raise ValueError("HPD: bad request")
if info.findtext("packet_error") == "True":
    raise ValueError("HPD: could not decode packet")

Examples: JavaScript

Fetch and parse XML

const params = new URLSearchParams({
  data:  "4500002852924000408837498B85CCB08B85CCB7800004D2000CF53F68656C6C6F20776F726C640A000000000000",
  force: "ipv4",
});

const res  = await fetch(`https://hpd.gasmi.net/api?${params}`);
const text = await res.text();
const xml  = new DOMParser().parseFromString(text, "text/xml");

const error = xml.querySelector("request_error")?.textContent;
if (error === "True") throw new Error("HPD request error");

xml.querySelectorAll("packet > proto").forEach(proto => {
  console.log(proto.getAttribute("name"), proto.getAttribute("showname"));
});

💡 The API is free for reasonable use. If you rely on it heavily in a production system, consider contacting us about a dedicated instance.

HPD by Salim Gasmi — packet decoding powered by Wireshark / tshark — hpd.gasmi.net