Tracking & Visibility

Shipment tracking is the ability to monitor a package's journey from origin to destination in real time. Every parcel carrier assigns a unique tracking number when a shipping label is created, and that number becomes the key to visibility — allowing shippers, recipients, and intermediaries to see where the package is, what's happening to it, and when it will arrive.

Tracking has transformed from a carrier-only tool into a customer expectation. In e-commerce, tracking links are embedded in order confirmation emails, and customers check their package status multiple times a day. For logistics professionals, tracking data is essential for exception management, performance analytics, and customer service.

This article explains how tracking works, what tracking events mean, and how visibility platforms aggregate data across carriers.

What is a Tracking Number

A tracking number (also called a tracking ID or shipment identifier) is a unique alphanumeric code assigned by the carrier to a specific package. It serves as the primary key in the carrier's database, linking all scans, status updates, and delivery information to that shipment.

Tracking numbers are:

• Globally unique — no two packages from the same carrier will ever have the same tracking number (though carriers may reuse numbers after several years)
• Encoded in barcodes — printed as 1D and 2D barcodes on the shipping label for automated scanning
• Carrier-specific — each carrier uses its own format, making it easy to identify which carrier a tracking number belongs to

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Tracking numbers are generated when the shipping label is created, not when the package is picked up. You can track a package before it enters the carrier's network — the first event will be "Label Created" or "Shipping Information Received."

Tracking Number Formats by Carrier

Each carrier uses a distinct format for tracking numbers. Understanding these patterns helps validate input, identify the carrier, and troubleshoot issues.

Carrier	Format	Length	Pattern	Example
UPS	Alphanumeric	18 chars	Starts with "1Z"	1Z999AA10123456784
FedEx Express	Numeric	12 digits	All digits, no prefix	9876 5432 1098
FedEx Ground	Numeric	15 digits	All digits	1234 5678 9012 345
USPS	Alphanumeric	20-22 chars	Format: AA 000000000 BB	9400 1000 0000 0000 0000 00
DHL Express	Numeric	10-11 digits	All digits	1234567890
DHL eCommerce	Alphanumeric	14 chars	Format: GM000000000000	GM12345678901234
Amazon Logistics	Alphanumeric	15 chars	Starts with "TBA"	TBA123456789012

UPS Tracking Number Structure

UPS tracking numbers follow the format: 1Z [6-char shipper number] [2-char service code] [8-digit package number] [1 check digit]

Example: 1Z999AA10123456784

• 1Z = UPS prefix
• 999AA1 = shipper account identifier
• 01 = service code (e.g., Ground, Next Day Air)
• 12345678 = sequential package number
• 4 = check digit (calculated from previous digits)

USPS Tracking Number Structure (S10 Standard)

USPS uses the Universal Postal Union (UPU) S10 standard for international mail tracking:

Format: AA 000000000 BB

• AA = service type (2 letters)
  • EA, EB, EC = Express Mail
  • LK, LN = First-Class Package International
  • CP = Priority Mail International
• 000000000 = 9-digit unique identifier
• 9 = check digit
• BB = country code (e.g., US for United States)

Example: EA 123456789 US (Express Mail International)

Domestic USPS tracking numbers may use 20-22 digit numeric formats without letters, particularly for Priority Mail and USPS Tracking services.

FedEx Tracking Number Types

FedEx uses different formats depending on the service:

• 12-digit = FedEx Express (air services)
• 14-digit = FedEx Express alternate format
• 15-digit = FedEx Ground
• 20-digit = FedEx SmartPost (USPS final mile)
• 22-digit = FedEx Ground barcode with service code prefix

Auto-Detect Carrier by Tracking Number

Many tracking platforms (Google, AfterShip, 17track) can automatically detect the carrier from the tracking number format. Simply paste the number into a search, and the system will route it to the correct carrier.

How Tracking Works

Tracking is powered by barcode scanning at every touchpoint in the carrier's network. Each scan creates a tracking event that updates the shipment's status in the carrier's database.

Tracking Event Lifecycle

A typical parcel tracking history includes these stages:

1. Label Created / Shipping Information Received
   The carrier receives electronic shipping data but has not yet physically received the package.

2. Picked Up / Accepted
   The carrier takes possession of the package (either at a drop-off location or via scheduled pickup).

3. In Transit
   The package is moving through the carrier's network. Multiple "In Transit" events may occur as the package arrives at and departs from sorting hubs.

4. Out for Delivery
   The package is loaded on a delivery vehicle and will be delivered today.

5. Delivered
   The package has been successfully delivered. The event typically includes:

   • Delivery date and time
   • Location (front door, mailbox, reception desk, etc.)
   • Signature (if required)

6. Exception (if problems occur)
   An unexpected event has interrupted normal delivery. See Tracking Event Types below.

Complete Tracking State Machine

The following diagram shows all possible tracking states and transitions throughout the shipment lifecycle:

State Descriptions

State	Description	Typical Duration	Next Steps
Label Created	Shipping label printed, carrier notified electronically	0-24 hours	Wait for carrier pickup or drop-off
Picked Up	Carrier physically received package	0-4 hours	Package moves to origin hub
At Origin Hub	Package at first carrier facility	2-12 hours	Sorted and loaded for transport
In Transit	Package moving between facilities	1-7 days (domestic), 5-30 days (international)	Continue monitoring
At Sort Hub	Package at intermediate sorting facility	2-8 hours	Sorted and forwarded to destination
At Destination Hub	Package at final carrier facility before delivery	4-24 hours	Loaded for local delivery
Out for Delivery	Package on delivery vehicle	4-12 hours	Delivery expected today
Delivery Attempt	Delivery attempted but failed	24 hours	Carrier will reattempt or leave notice
Held for Pickup	Package available at carrier facility or access point	5-7 days	Recipient must collect package
Exception	Problem preventing normal delivery	Varies (hours to weeks)	Investigate exception reason
Delivered	Successfully delivered to recipient	Terminal state	—
Picked Up by Recipient	Recipient collected package from carrier location	Terminal state	—
Return to Sender	Package being returned to shipper	3-10 days	Shipper will receive package back
Cancelled	Shipment cancelled before entering network	Terminal state	—

Understanding "Stuck" Packages

If a package shows the same status for an extended period:

• In Transit >5 days (domestic): Package may be delayed or misrouted. Contact carrier after 5 business days.
• At Hub >48 hours: Backlog at facility or missed scan. Usually resolves automatically.
• Exception >3 days: Requires investigation. Contact carrier with tracking number.
• Label Created >48 hours: Package not yet picked up by carrier. Contact shipper to confirm handoff.

Tracking Event Types

Tracking events are status updates generated by barcode scans or manual entries. Understanding what each event means helps diagnose issues and set customer expectations.

Standard Events

Event	Meaning	Action
Label Created	Shipping label printed; carrier has not yet received package	Wait for pickup scan
Picked Up	Carrier took possession of package	Package is now in carrier network
In Transit	Package moving through sorting facilities	Normal progress
Arrived at Hub	Package reached a sorting facility	Normal progress
Departed Hub	Package left a sorting facility	Normal progress
Out for Delivery	Package on delivery vehicle; delivery expected today	Ensure recipient is available
Delivered	Package successfully delivered	Check delivery location/signature
Left at Door	Package delivered without signature (contactless)	Verify package was retrieved

Exception Events

Exceptions are deviations from the normal delivery flow. They require attention and may delay delivery.

Event	Meaning	Action
Delivery Exception	Unspecified problem preventing delivery	Check tracking details; contact carrier
Address Error	Destination address is incomplete or invalid	Correct address with carrier; may require new label
No Access to Delivery Location	Driver could not reach delivery address (gated community, locked building)	Recipient should arrange access or pickup
Recipient Not Available	Delivery attempted but recipient not home (signature required)	Carrier will reattempt delivery; recipient can schedule
Weather Delay	Severe weather preventing delivery	Delivery will resume when conditions improve
Held at Customs	International shipment held for customs clearance	Recipient must provide required customs documents or pay duties
Damaged in Transit	Package damaged during handling	Carrier will inspect; may return to sender
Lost in Transit	Package cannot be located	File claim with carrier
Returned to Sender	Package being returned (undeliverable, refused, unclaimed)	Shipper will receive package back; investigate cause

Stuck at "In Transit" Status

If a tracking number shows "In Transit" with no updates for several days, it may indicate:

• Scanning missed — package was sorted but not scanned
• Delayed at hub — backlog due to volume or weather
• Lost — package misrouted or misplaced

Contact the carrier after 5 business days (domestic) or 10 business days (international) with no updates.

Accessing Tracking Information

There are four main ways to track a package:

1. Carrier Websites

Each carrier provides a tracking portal on their website:

Carrier	Tracking URL
USPS	tools.usps.com
UPS	ups.com/track
FedEx	fedex.com/tracking
DHL	dhl.com/tracking

Simply enter the tracking number and view the shipment history.

2. Multi-Carrier Tracking Platforms

Third-party platforms aggregate tracking data from multiple carriers into a single interface. This is useful when you ship with multiple carriers or need tracking for customers who may not know which carrier is handling their order.

Popular platforms:

Platform	Features	Link
AfterShip	1,100+ carriers, tracking API, branded tracking pages	aftership.com
17track	2,400+ carriers, free for consumers	17track.net
ParcelsApp	Multi-carrier tracking, mobile apps	parcelsapp.com
Shippo	Multi-carrier API for developers, rate shopping	goshippo.com
ShipStation	E-commerce shipping platform with tracking	shipstation.com

3. Carrier APIs

For developers and logistics platforms, carriers provide tracking APIs that return structured JSON or XML data.

Example: UPS Tracking API Request

GET /api/track/v1/details/{trackingNumber}
Host: onlinetools.ups.com
Authorization: Bearer {access_token}

Response (simplified):

{
  "trackingNumber": "1Z999AA10123456784",
  "status": "In Transit",
  "currentLocation": "Louisville, KY",
  "estimatedDelivery": "2026-02-12T17:00:00Z",
  "events": [
    {
      "status": "Departed Hub",
      "location": "Louisville, KY",
      "timestamp": "2026-02-10T08:30:00Z"
    },
    {
      "status": "Arrived at Hub",
      "location": "Louisville, KY",
      "timestamp": "2026-02-09T22:15:00Z"
    }
  ]
}

4. Email and SMS Notifications

Carriers offer tracking notifications sent directly to the recipient or shipper:

• USPS Informed Delivery — daily email with images of incoming mail and package tracking
• UPS My Choice — email/SMS notifications for packages being delivered to your address
• FedEx Delivery Manager — customize delivery preferences and receive alerts
• DHL On Demand Delivery — delivery notifications and rescheduling options

Proactive Customer Communication

For e-commerce sellers, send tracking links to customers immediately after shipping. Use platforms like Klaviyo, ShipStation, or AfterShip to automate tracking emails with branded tracking pages.

Visibility Platforms and Real-Time Tracking

Visibility platforms go beyond simple tracking — they provide real-time location data, predictive ETAs, and exception alerts across the entire supply chain.

How Visibility Platforms Work

1. Carrier API integration — the platform connects to carrier tracking APIs and polls for updates
2. Normalization — standardizes event data from different carriers into a unified format
3. Predictive analytics — uses historical data to predict delays and adjust ETAs
4. Alerts — sends notifications when shipments are delayed or encounter exceptions
5. Dashboards — provides visual analytics on shipment performance, carrier SLAs, and on-time delivery rates

Visibility Platform Use Cases

User	Use Case
E-commerce sellers	Branded tracking pages, automated delivery notifications, reduce "where is my order" inquiries
3PLs & freight forwarders	Monitor shipments across multiple carriers, proactive exception management
Shippers	Carrier performance analytics, compare on-time delivery rates, optimize carrier selection
Customers	Real-time delivery updates, reschedule delivery, track multiple packages in one place

Leading Visibility Platforms

Platform	Focus	Key Features
AfterShip	E-commerce post-purchase tracking	1,100+ carriers, branded tracking pages, Shopify/WooCommerce integration, delivery notifications
Shippo	Shipping API & tracking for developers	Multi-carrier API, rate shopping, tracking webhooks, address validation
ShipStation	E-commerce shipping & fulfillment	Label generation, order management, tracking, carrier integrations (300+)
EasyPost	Developer-focused shipping API	RESTful API, tracking webhooks, address validation, carrier selection logic
ParcelPerform	E-commerce delivery experience	Predictive delivery dates, proactive exception alerts, returns tracking

Tracking Data Standards

While each carrier uses its own tracking event terminology, industry efforts aim to standardize tracking data for easier integration.

GS1 EPCIS (Electronic Product Code Information Services)

EPCIS is an open standard for sharing supply chain event data. It defines:

• What was observed (product/package ID)
• When it was observed (timestamp)
• Where it was observed (location)
• Why it was observed (business process context)

Carriers and logistics providers can exchange tracking data in EPCIS format to provide end-to-end visibility across multiple parties.

ISO 9735 (EDIFACT)

EDIFACT is the international EDI standard that includes message types for shipment tracking (IFTSTA — International Forwarding and Transport Status message). Legacy systems often use EDIFACT for tracking data exchange.

Best Practices for Tracking Management

1. Always Provide Tracking Links to Customers

Include tracking numbers in order confirmation and shipment notification emails. Make the tracking number a clickable link to the carrier's tracking page.

2. Monitor for Exceptions Proactively

Don't wait for customers to complain. Use a visibility platform or carrier notifications to alert you when shipments are delayed or encounter exceptions.

3. Set Realistic Delivery Expectations

Use carrier transit time maps and historical performance data to communicate accurate delivery estimates. Don't promise 2-day delivery if the carrier's service level is 3-5 days.

4. Track Carrier Performance

Analyze on-time delivery rates, exception rates, and average transit times by carrier and service level. Use this data to optimize carrier selection and negotiate better rates.

5. Integrate Tracking with Customer Support

Your customer service team should have access to tracking data in their CRM or helpdesk tool. This reduces "where is my order" ticket resolution time from minutes to seconds.

Resources

Resource	Description	Link
USPS Tracking	Official USPS package tracking portal	tools.usps.com
UPS Tracking	Official UPS package tracking portal	ups.com/track
FedEx Tracking	Official FedEx tracking portal	fedex.com/tracking
AfterShip Tracking API	Multi-carrier tracking API for developers	aftership.com/tracking-api
17track Multi-Carrier Tracking	Free tracking for 2,400+ carriers	17track.net
GS1 EPCIS Standard	Open standard for supply chain event data	gs1.org/epcis

Related Topics

• Shipping Labels — how tracking numbers are generated and encoded on labels
• Last-Mile Delivery — the final step of the delivery journey
• Returns Management — tracking return shipments back to the seller