Tag
USPS v3, from enrollment to production
The v3 migration is more than an endpoint swap. Use this collection to move from business enrollment and OAuth through route mapping, rate limits, and production recovery.
16 reviewed guides
01
CRID, MID, EPA, and license setup
02
OAuth and route-level implementation
03
Rate limits, errors, and production recovery
- USPS v3
- Pricing
- Address Validation
- Vendor Comparison
- Web Tools Migration
- Districts
- Redistricting
- Troubleshooting
- USPS License
- OAuth
- Quickstart
- Rate Limits
- API Governance
- Customs
- EasyPost
- Ecommerce Platforms
- International Shipping
- Migration
- USPS Enrollment
- Architecture
- BYOK
- Checkout
- Data Quality
- PHP
- Political Mail
- Reference
- SDK
- SDKs
- Tracking
EasyPost Migration Guide: Moving USPS Shipping Off EasyPost
The endpoint mapping, working code, and BYOK setup for moving USPS address validation, rates, tracking and labels off EasyPost. Plus the USPS license step.
10 min readUSPS API Access Control: What April 1, 2026 Actually Changed
USPS switched tracking from possession-based to identity-based access on April 1, 2026. What landed, who it hit, and how it led to the August license.
9 min readusps-api and usps-webtools Are Dead: the 2026 Replacement
The usps-api, usps-webtools, and usps-webtools-promise packages target an API that no longer exists. The errors you are seeing, and the one-command swap.
9 min readUSPS API Rate Limits in 2026: From 6,000/min to 60/hour
USPS v3 throughput fell from roughly 6,000 requests a minute on Web Tools to 60 per hour. What that does to checkout at peak, and five architecture patterns.
12 min readUSPS April 2026 Access Control: The Architecture That Survived It
Access Control landed April 1 and the license regime followed on August 1. The integration shape that absorbed both, and the checks to run now.
8 min readUSPS Batch Address Validation: 50 Addresses per Call
Validate 50 US addresses in one request. The exact payloads, per-address failure handling, rate-limit backoff, and how to run a 10,000-row list through it.
10 min readUSPS v3 Address Validation: One Request, Start to Finish
The USPS v3 address call in curl, Python and Node: OAuth, the required parameters, every DPV code, and the license USPS has required since August 1, 2026.
9 min readUSPS v3 Migration Guide: Node.js and Python, XML to REST
Every Web Tools operation rewritten in the usps-v3 Python and Node SDKs, with the exact method names, the field that silently fails, and a cutover playbook.
15 min readUSPS Node.js SDK Quickstart: TypeScript Client for the v3 API
Install usps-v3, authenticate once, and call address validation, tracking, rates, and labels from Node. Zero dependencies, typed errors, Express route.
12 min readUSPS v3 API with PHP: Complete Quickstart Guide
Install revaddress/usps-v3-php and call the USPS v3 REST API from PHP: validation, tracking, rates, labels, plus Magento, WooCommerce and Laravel wiring.
12 min readUSPS Python SDK Quickstart: Validate, Track, and Rate with usps-v3
Install usps-v3, authenticate once, and call address validation, tracking, and rates from Python. Working code, real return shapes, typed errors.
11 min readUSPS v3 SDK for Python and Node.js: Endpoints, Credentials, and the OAuth You Do Not Have to Write
The usps-v3 SDKs for Python and Node.js at v1.0.4. Real method signatures, which calls need Payment Authorization, error classes, and token handling.
9 min readUSPS Web Tools to v3 REST API: Complete Endpoint Mapping
Every Web Tools XML API mapped to its v3 REST route, with the auth change, the reversed address fields, and the gotchas that break production migrations.
12 min readUSPS Web Tools Migration Checklist (2026)
A numbered checklist for moving off USPS Web Tools XML: endpoint map, the license now required, OAuth, field mapping, error mapping, and the cutover.
14 min readUSPS Web Tools Shut Down on January 25, 2026: What Broke and the Fastest Way to the v3 API
USPS retired Web Tools on January 25, 2026. If ShippingAPI.dll, USERID, or secure.shippingapis.com is failing, map the XML route to v3 REST here.
10 min readUSPS Web Tools Migration: XML to v3 REST, End to End
Every Web Tools endpoint mapped to its v3 REST equivalent, the OAuth flow in three languages, the field swap that corrupts addresses, and the 60/hr wall.
12 min read