Comparing Shipping Tracking APIs: The Dev's Verdict

You've been tasked with integrating shipment tracking, and the API you pick decides how many engineering hours go into carrier data and missed webhooks later. On the facts each vendor publishes, meaning status depth, carrier coverage, webhook retries and uptime commitment, the AfterShip Tracking API is the stronger choice for multi-carrier, high-volume builds. It publishes 9 statuses with 52 sub-statuses, 1,700+ carriers, up to 14 webhook delivery attempts and a 99.9% uptime SLA with service credits, available from the Silver support plan.

The Developer's Dilemma: Choosing a Tracking API That Doesn't Create Technical Debt

The task usually arrives as one line in a sprint plan: pick a tracking API. What you are actually picking is a piece of infrastructure that every order in the system will pass through, and that someone on your team will maintain for years.

Feature lists are the least useful way to make that call. The questions that decide the cost are whether the data model holds up as you add carriers, whether the service stays available through peak, and how much code you end up writing to cover the gaps. AfterShip, EasyPost and Shippo all publish a tracking API, and all three will return a delivery status for a package.

The work around the API is where the hours go. Ask in developer communities what it takes to integrate a carrier's tracking API directly and you get threads like the Stack Overflow question from a developer working with UPS, where the top answer notes that the UPS Track by Reference API does not properly document its pickup date parameters.

That is one carrier.

This is also the moment for choosing between a direct API integration and a pre-built app, because the answer changes what you are evaluating and how long the build takes.

A developer comparing tracking API documentation before committing engineering time.

The Developer Scorecard: How We're Rating Tracking APIs in 2026

This shipping tracking api comparison scores each vendor on five criteria, and only on evidence each one publishes: developer documentation, status pages, contractual terms and pricing pages.

• Data Accuracy & Carrier Coverage. The status model is the contract between the carrier network and your code. A shallow model pushes carrier-specific handling into your application, and thin coverage means building direct carrier integrations yourself.
• API Reliability & Performance (Uptime/Latency). You are putting a third party in the path of every order. What matters is the commitment the vendor makes in writing, and whether you can see incidents without contacting support.
• Developer Experience (DX): Docs, SDKs & Time-to-First-Call. Time to first call here means request simplicity: how many fields a create call requires, how authentication is handled, and what shape the response comes back in. An official SDK in your language means no wrapper code of your own.
• Webhook Architecture & Reliability. Tracking is event-driven. Retry depth and signature validation decide whether a brief outage on your side becomes a silent data gap.
• Scalability & Pricing Model. Rate limits and billing terms determine what happens on your busiest day, and what the integration costs once volume is real.

On G2, read September 2026, AfterShip holds 4.7/5 from 311 reviews in the E-Commerce Tools category, EasyPost holds 4.2/5 from 122 reviews in Shipping Software, and Shippo holds 4.2/5 from 77 reviews in Shipping Software.

Round 1: Data Accuracy & Carrier Coverage

AfterShip's Tracking API standardizes data from over 1,700 carriers into nine statuses. That model is where a multi-carrier tracking api earns or loses its keep.

All three APIs normalize tracking statuses. AfterShip publishes 9 statuses with 52 sub-statuses, EasyPost publishes 10 status values with 28 status-detail values, and Shippo publishes 6 statuses with 27 substatus codes.

AfterShip's edge is that depth applied across coverage. Its sub-statuses sit beneath the top-level statuses as one normalized data model, and that single schema covers every carrier AfterShip supports.

AfterShip's carrier directory states support for 1,700+ carriers worldwide, read September 2026.

EasyPost publishes 100+ carriers. Shippo lists 1000+ carriers for tracking in the plan comparison on its API pricing page. A carrier outside a vendor's coverage is one you integrate and map yourself, and the widest published coverage of the three leaves the fewest of those.

Keeping a directory that size current is operational work. AfterShip runs a carrier integration team that onboards carriers through its carrier partner program; the team reviews each carrier's application and sends the integration agreement along with a file for the carrier's API information.

That depth is what platforms build on when tracking data is the product, and it is visible in how leading technology platforms leverage this visibility. For teams weighing the data layer specifically, we have also published a direct comparison against other data providers like Parcel Perform.

For a multi-carrier build, this is the foundation the remaining four rounds sit on: one schema to learn and maintain.

Round 2: API Reliability & Performance

AfterShip publishes a 99.9% Service Uptime SLA backed by a service-credit schedule, available from the Silver support plan, with data processing agreements and security certifications on Enterprise. AfterShip's API uptime is backed by a public SLA and status page.

EasyPost's Master Customer Agreement carries no uptime commitment and no service-credit schedule, and its 99.99% historic uptime figure appears on its Shipping API page as a performance claim, not a contractual one.

Shippo lists a 99.9% uptime SLA on its Premier subscription plan, with no remedy stated alongside it.

AfterShip is the only one of the three publishing a service-credit schedule, which is the part of an SLA that decides what a missed month is actually worth to you.

What an SLA buys you is recourse. Check three things before you sign: the percentage, the measurement window, and whether anything happens when the number is missed.

All three run public API status pages, and each reports on its own terms. AfterShip's page breaks uptime out per service across Day, Week and Month views. EasyPost's page reports uptime over the past 90 days by component. Shippo's page reports component status alongside a response-time chart.

Because the windows differ, the pages do not line up against each other. Use each for what it is good at: confirming an incident you are already seeing, and checking a vendor's recent record before you commit.

Round 3: Developer Experience (DX)

AfterShip publishes official Tracking API SDKs in seven programming languages. Those languages are Java, .NET, PHP, Ruby, Python, Node.js and Go, and the official API documentation carries a complete API reference and quickstart guides alongside them.

An official library in your language makes it a dependency you add rather than a component you own and patch.

The create call tells you more, because it shows how much the API asks of you before it will accept a shipment.

Here is a create-a-tracking request against AfterShip, in Python and as a curl command. tracking_number is the only required field in the body.

import requests

url = "https://api.aftership.com/tracking/2026-07/trackings"
headers = {
    "as-api-key": "YOUR_API_KEY",
    "Content-Type": "application/json",
}
payload = {"tracking_number": "1234567890"}

r = requests.post(url, headers=headers, json=payload)

# The response wraps the tracking in meta and data.
print(r.json()["meta"]["code"])  # 201 on create
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curl -X POST \
  https://api.aftership.com/tracking/2026-07/trackings \
  -H "as-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"tracking_number": "1234567890"}'
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AfterShip's create response wraps the new tracking in a data object, with the status code in meta.

The same call against EasyPost uses HTTP Basic authentication, with the API key as the username, and nests the tracking code inside a tracker object.

import requests

url = "https://api.easypost.com/v2/trackers"
payload = {"tracker": {"tracking_code": "EZ1000000001"}}

r = requests.post(url, auth=("YOUR_API_KEY", ""), json=payload)
print(r.json()["id"])
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curl -X POST https://api.easypost.com/v2/trackers \
  -u "YOUR_API_KEY:" \
  -H "Content-Type: application/json" \
  -d '{"tracker": {"tracking_code": "EZ1000000001"}}'
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EasyPost's carrier field is optional and auto-detected, and its documentation recommends supplying it because some tracking codes match more than one carrier. Shippo's POST /tracks/ requires both carrier and tracking_number.

The difference shows up first in a backfill. If you are loading historical shipments and your records do not carry a normalized carrier name, an API that accepts the tracking number alone lets you start before you have built a carrier lookup table.

Three shapes, three sets of required fields. Each API is a short call once you have credentials. What differs is how much you have to know up front, and how much of that knowledge ends up hard-coded in the ingestion layer you maintain.

Round 4: Webhook Architecture

AfterShip attempts delivery of a webhook up to 14 times on an exponential back-off, calculated as 2^n x 30 seconds, and after the fourteenth attempt that webhook is not sent again. Every request carries an aftership-hmac-sha256 header: a base64 HMAC-SHA256 of the request body, signed with your account's webhook secret, documented on the webhook signature page.

Validate that signature before you trust the payload. A webhook endpoint is a public URL, and the HMAC is what separates a carrier update from anything else that finds it.

Event triggers and the signature key are configured in the dashboard, which matters when the person changing a webhook setting at 2 a.m. is not the person who wrote the integration.

EasyPost retries a failed webhook up to six times with an increasing delay, expects a response within seven seconds, and signs each event with an X-Hmac-Signature header.

Shippo expects a 2XX within three seconds and retries twice on a timeout or a 408, 429 or 5XX response. Its documentation also notes that tracking webhooks are not idempotent, so a duplicate registration can produce more than one notification for the same event.

Retry depth sets how many chances a delivery gets before the gap becomes permanent, and AfterShip publishes the most attempts of the three. Plan for the ceiling regardless.

A reconciliation pull is the cheap insurance: a scheduled job that re-fetches trackings updated since your last confirmed event. That turns a missed webhook into minutes of stale data rather than a silent hole you find weeks later.

Round 5: Scalability & Pricing

AfterShip, EasyPost and Shippo all publish their tracking prices on public pages, which makes this the rare part of a developer review of shipping tracking APIs you can settle before you talk to anyone.

AfterShip includes the Tracking API on its Premium plan and on Enterprise, with Tracking priced by annual shipment volume and billed monthly or annually.

EasyPost charges per shipment tracked, or bundles tracking with its Shipping API. Shippo charges per track on its API Starter plan, and includes tracking for shipments created on Shippo.

On published rates, AfterShip's per-tracker price is higher than EasyPost's or Shippo's.

Total cost of ownership also turns on engineering effort, through two mechanisms from Round 1.

The sub-status depth means fewer carrier-specific status mappings to maintain. The carrier coverage means fewer direct carrier integrations to build.

Scale has a second dimension, and it is the one that decides what happens on your busiest day. AfterShip's rate-limit documentation sets a limit per endpoint, for example 20 requests per second to create a tracking. Its pricing page states a plan limit of 10 requests per second on Premium, and a custom limit on Enterprise.

The Final Verdict: The Developer's Choice for 2026

Taken together, the five rounds point the same way: the three APIs are close at the first request, and the distance opens in the parts of an integration you maintain after launch.

That holds whether you frame this as an AfterShip vs EasyPost API decision or weigh all three, and it is the test that settles the best shipping API for developers in your position: match the API to your carrier mix, your volume and the commitments you need in writing.

If your manager wants the same argument without the endpoints, AfterShip's own platform comparison covers it at a product level.

Once carrier mix, volume and published reliability commitments start to matter, AfterShip is the specialist choice for developers building at scale.

Round-by-Round Summary

Five rounds, three vendors, one row each.

When to Choose AfterShip (And When to Consider an Alternative)

Choose AfterShip if:

• You need one normalized status schema, 9 statuses with 52 sub-statuses, applied across the widest published carrier coverage of the three at 1,700+ carriers.
• You need the most published webhook delivery attempts, up to 14.
• You need a published uptime SLA carrying service credits, available from the Silver support plan.

When an alternative fits:

• Consider EasyPost or Shippo if your shipments already run on their labels, where tracking is bundled or included.

Once you track shipments you did not label with them, that bundling no longer applies.

Frequently Asked Questions

Which tracking API supports the most carriers?

All three publish a carrier count. EasyPost publishes support for more than 100 carriers. Shippo lists 1000+ carriers for tracking in the plan comparison on its API pricing page. AfterShip's carrier directory states support for 1,700+ carriers worldwide, the highest published count here.

Do I have to send the carrier when I create a tracking?

It depends on the API. Shippo requires both the carrier and the tracking number on its create-a-track endpoint. EasyPost treats the carrier as optional and auto-detects it, though its documentation recommends supplying it because some tracking codes match more than one carrier. AfterShip asks for the tracking number alone, so you can create a tracking with the number a customer already has.

What happens if my webhook endpoint is down?

Each vendor retries, then stops. Shippo retries twice after a timeout or a 408, 429 or 5XX response. EasyPost retries up to six times with an increasing delay. AfterShip attempts delivery up to 14 times on a published exponential back-off, so a briefly unavailable endpoint has more chances to come back before the update is lost.

Which tracking API publishes an uptime SLA?

Two of the three do. EasyPost's Master Customer Agreement carries no uptime commitment. Shippo lists a 99.9% uptime SLA on its Premier subscription plan. AfterShip publishes a 99.9% Service Uptime SLA backed by a service-credit schedule, which the Silver support plan and above carry, so a missed month has a stated consequence.