4PX Express Tracking API & MCP

Query live 4PX Worldwide Express (4px, 递四方) cross-border package status, scan history, and domestic last-mile handoff numbers in a single synchronous GET request or MCP tool call. lastscanned auto-detects 18-character 4PX…CN tracking numbers, repairs 4PX's cross-timezone chronological sorting bug, and returns a normalized TrackingResult JSON payload.

Overview & Quick FactsCopy Anchor Link

Why developers use lastscanned for 4PX ExpressCopy Anchor Link

• Fixes 4PX's broken cross-timezone scan ordering: 4PX's upstream API computes its tkDate epoch by interpreting every scan's local wall-clock time (tkDateStr) as Beijing time (UTC+8)—ignoring the scan's actual tkTimezone (UTC-05:00). Because US local wall-clock times are 12–13 hours behind Shenzhen, 4PX sorts Chinese export scans above US last-mile scans that occurred hours later in real UTC time. lastscanned ignores the broken tkDate epoch, computes true UTC from tkDateStr + tkTimezone, and re-sorts the timeline in true chronological order.
• Surfaces last-mile carrier & exchange number in message: When 4PX hands a parcel to USPS, UniUni, or another domestic carrier, lastscanned extracts both channelContact (the carrier name) and serverCode (the domestic tracking number) into message.

Tracking Number Formats & Auto-Detection (matches vs mayMatch)Copy Anchor Link

4PX is evaluated sixteenth (#16) in lastscanned's two-pass detector:

When is ?carrier=4px optional vs required?Copy Anchor Link

• Optional (auto-detected): All 18-character 4PX + 13 digits + CN tracking numbers auto-detect in Pass 1.
• Required (?carrier=4px): When querying 4PX's system using the domestic last-mile barcode (e.g. a USPS 92… or Royal Mail S10 number that was inducted by 4PX) or a custom merchant order number.

Synchronous GET Request & Normalized JSON ResponseCopy Anchor Link

curlCopy Anchor Link

curl -s "https://api.lastscanned.com/v1/track/4PX3002491827361CN" \
  -H "Authorization: Bearer $LASTSCANNED_API_KEY"

JavaScript / TypeScript (fetch)Copy Anchor Link

const res = await fetch("https://api.lastscanned.com/v1/track/4PX3002491827361CN", {
  headers: { Authorization: `Bearer ${process.env.LASTSCANNED_API_KEY}` },
});
const pkg = await res.json();
console.log(pkg.status, pkg.message, pkg.events[0]);

MCP track_package tool callCopy Anchor Link

{
  "tool": "track_package",
  "arguments": {
    "tracking_number": "4PX3002491827361CN"
  }
}

Normalized TrackingResult JSON responseCopy Anchor Link

{
  "carrier": "4px",
  "trackingNumber": "4PX3002491827361CN",
  "status": "delivered",
  "statusDescription": "Delivered, In/At Mailbox",
  "service": null,
  "deliveredAt": "2026-10-24T19:22:00Z",
  "deliveredAtLocal": "2026-10-24T14:22:00",
  "signedBy": null,
  "destination": {
    "city": null,
    "state": null,
    "country": "US"
  },
  "estimatedDelivery": null,
  "message": "Handed to USPS as 9261290312839104827163",
  "events": [
    {
      "timestamp": "2026-10-24T19:22:00Z",
      "localTime": "2026-10-24T14:22:00",
      "status": "delivered",
      "description": "Delivered, In/At Mailbox",
      "location": "DALLAS, TX 75201",
      "code": "FPX_L_ok"
    },
    {
      "timestamp": "2026-10-24T11:15:00Z",
      "localTime": "2026-10-24T06:15:00",
      "status": "out_for_delivery",
      "description": "Out for Delivery",
      "location": "DALLAS, TX 75201",
      "code": "FPX_I_RC"
    },
    {
      "timestamp": "2026-10-20T16:40:00Z",
      "localTime": "2026-10-21T00:40:00",
      "status": "in_transit",
      "description": "Depart from facility to service provider.",
      "location": "Shenzhen, China",
      "code": "FPX_C_BTC"
    },
    {
      "timestamp": "2026-10-18T03:12:00Z",
      "localTime": "2026-10-18T11:12:00",
      "status": "label_created",
      "description": "Shipment information received",
      "location": null,
      "code": "FPX_O_CR"
    }
  ]
}

Raw status & scan codes: events[].code preserves 4PX's tkCode ("FPX_O_CR" → label_created, "FPX_C_..." / "FPX_M_..." → in_transit, "FPX_I_RC" → out_for_delivery when out for delivery, "FPX_L_ok" → delivered, "FPX_L_RPI" → returned).

Chaining Last-Mile Handoffs (message)Copy Anchor Link

When 4PX assigns a secondary domestic tracking number (serverCode) different from the 4PX…CN number, lastscanned populates message with:

• "Handed to USPS as 9261290312839104827163" (when channelContact identifies the last-mile carrier), or
• "Handed to the destination carrier as <serverCode>"

You can pass that secondary tracking number directly into a follow-up GET /v1/track/{serverCode} call to retrieve native last-mile scans from USPS, UniUni, GOFO, or OnTrac.

Related ResourcesCopy Anchor Link

• Live browser lookup tool: Track a 4PX Express package live on lastscanned.com/lookup/4px
• Carrier hub: All 31 supported carriers
• Regex & check digits: Tracking number formats & auto-detection
• AI support workflows: WISMO AI agents & synchronous tracking