Getting Started with the Shipping Label API

If your business ships thousands of orders programmatically — or you're building a product that offers shipping as a feature — manually printing labels through a web app simply doesn't scale. The Shipping Label API lets you generate labels, validate addresses, get rate quotes, and manage orders entirely in code, so your fulfillment workflow runs fast, reliably, and without human intervention. This guide walks you through everything you need to get up and running.

Who the Shipping Label API Is For

The shipping label API is the integration path for businesses that want to generate labels programmatically rather than through the web app. It's built for three common scenarios:

• An e-commerce platform that fulfills orders without a human in the loop

• A warehouse management system that prints labels in batch from a nightly job

• A SaaS product that resells shipping as a feature to its own customers

If you're a single seller printing fifty labels a day through the web app, you probably don't need the API. But if you're processing thousands of shipments programmatically — or building a product on top of shipping — the API is exactly what you want.

Getting an API Key

API keys are issued per user account. To get started:

1. Sign in to your account.

2. Navigate to the API page in your account settings.

3. Request a new key — it is shown exactly once, so copy it to your secrets store immediately.

Treat your API key like a password. Anyone who holds the key can generate labels billed to your account, so never expose it in client-side code, public repositories, or unencrypted configuration files.

How the API Works

The shipping label API exposes the same core operations as the web app, all accessible via JSON endpoints with Bearer token authentication in the Authorization header. The primary endpoints include:

• Address verification — validate and correct a shipping address before committing to a label

• Rate quotes — get a price estimate for a shipment before generating the label

• Label generation — create a ready-to-print shipping label

• Order status query — check the current status of a shipment

• Order history — list past orders for reporting or reconciliation

• Label PDF download — retrieve the label file for printing

Every endpoint accepts JSON and returns JSON, making integration straightforward in any language or framework. A typical label-generation flow looks like this:

1. Validate the address. POST the shipping address to the address-verification endpoint. The response includes a corrected version if the input was close but not exact.

2. Get a rate quote. Submit the origin, destination, and package details to retrieve available service options and prices.

3. Generate the label. Once you've selected a rate, call the label-generation endpoint to create and lock in the shipment.

4. Download the PDF. Retrieve the label PDF for printing or pass the URL to your warehouse printing system.

Rate Limits and Errors

Understanding rate limits and error handling upfront saves you debugging time in production. The API uses standard HTTP status codes — 2xx for success, 4xx for client errors (bad input, missing fields, invalid address), and 5xx for server-side issues. Error responses return a JSON body with a machine-readable code and a human-readable message.

Rate limits are applied per API key. If you exceed the limit, you'll receive a 429 Too Many Requests response. Best practices for handling limits at scale:

• Implement exponential backoff with jitter on retries

• Batch address validation before peak fulfillment windows

• Cache rate quotes when the origin, destination, and package dimensions haven't changed

• Contact support if your volume regularly approaches the default limits — higher tiers are available

Where to Go from Here

Once you've successfully authenticated and generated your first label, the next steps depend on your use case. You can explore webhooks for real-time shipment status updates, set up batch label generation for nightly fulfillment jobs, or integrate the order-listing endpoint into your reporting dashboard.

The full API reference covers every endpoint parameter, response schema, and error code in detail. Start with the address-verification and rate-quote endpoints in a sandbox environment before moving to production, and always keep a fallback path to the web app for edge cases your automation doesn't handle.

Key Takeaways

• The shipping label API is designed for programmatic, high-volume, or product-embedded use cases — not for individual sellers using the web app.

• API keys are per-account, shown once, and must be stored securely; they authorize billing on your account.

• All endpoints use JSON with Bearer token authentication, mirroring the operations available in the web app.

• The standard label flow is: validate address → get rate quote → generate label → download PDF.

• Handle rate limits with exponential backoff and contact support for higher volume tiers.

• Test in a sandbox environment before going live, and keep the web app as a fallback for edge cases.

Ready to start generating shipping labels programmatically? Request your API key from the account settings page and follow this guide to integrate in minutes — no shipping expertise required, just clean JSON and a reliable fulfillment pipeline.