Blog
Technical guides for USPS API migration and shipping infrastructure.
USPS Web Tools Migration Checklist (2026): Every Step, In Order
Step-by-step checklist for migrating from USPS Web Tools XML to the v3 REST API. Covers OAuth, endpoint mapping, error handling, and testing — nothing skipped.
Shippo vs RevAddress: Which USPS API Is Right for You?
Head-to-head comparison of Shippo and RevAddress for USPS shipping. Pricing at every volume tier, architecture differences, code samples, and when to pick each one.
ShipEngine vs RevAddress: USPS API Comparison for Developers
ShipEngine vs RevAddress for USPS shipping integration. Pricing tiers, API design, code samples, and the real question: do you need 200 carriers or one really good one?
USPS API Pricing in 2026: What It Actually Costs (Direct vs Third-Party)
The USPS API is free to use directly — but rate limits make it impractical at scale. Here's the real cost breakdown for direct access, EasyPost, Shippo, and RevAddress.
Shipping API Comparison 2026: EasyPost vs Shippo vs ShipEngine vs RevAddress
Side-by-side comparison of shipping APIs for USPS integration. Pricing, rate limits, code samples, and migration paths. Updated for March 2026.
USPS v3 Address Validation in 30 Seconds
Validate a US address with the USPS v3 REST API in one curl command. Working code for Python, Node.js, and curl — no XML, no USERID, no middleman.
EasyPost March 17 Enforcement: Migration Options After Auto-Enrollment
EasyPost plan enforcement is live. Compare migration options with exact cost savings at 1K-50K labels/mo, side-by-side code examples, and a 5-step migration checklist.
USPS API Rate Limits in 2026: From 6,000/min to 60/hour (and How to Fix It)
USPS v3 API dropped from ~6,000 requests/min to 60/hour. Why it happened, what it means for production shipping, and five architecture patterns with working code to handle it.
USPS v3 Migration Guide for Node.js & Python: From Web Tools XML to REST
Step-by-step migration from USPS Web Tools XML to v3 REST using the usps-v3 Python and Node.js SDKs. Side-by-side code comparison, OAuth setup, endpoint mapping, and testing checklist.
USPS April 2026 Access Control Changes: Why You Should Migrate Now, Not Later
USPS is restructuring API access control in April 2026 — the second wave of breaking changes. Timeline, what's changing, action items, and how to build an integration that survives both waves.
EasyPost March 17 Enforcement: What Happened If You Didn't Choose a Plan
EasyPost plan enforcement is live. Free Access vs BYOCA explained, cost impact at every volume tier, and flat-rate alternatives.
USPS Web Tools Shutdown: Complete Guide to the January 2026 API Retirement
Everything you need to know about the USPS Web Tools XML API retirement. Timeline, impact, migration paths, and working code examples for the v3 REST API.
USPS API Access Control: What Changes in April 2026
USPS is launching its API Access Control initiative in April 2026, restricting tracking data access for service providers. What changes, who's affected, and how BYOK insulates you.
usps-api / usps-webtools Are Dead — Here's the 2026 Replacement
The usps-api PyPI package, usps-webtools, and usps-webtools-promise npm packages all target the retired USPS Web Tools XML API. They are broken. One-command migration to usps-v3.
USPS v3 SDK for Python, Node.js & PHP — Open Source, Production-Tested
Install the usps-v3 SDK for Python, Node.js, or PHP. Automatic OAuth, address validation, tracking routes, pricing, and managed USPS workflow support. MIT licensed with automatic token management.
Magento USPS AC-15210: Fix Broken Shipping After Web Tools Retirement
The AC-15210 patch swapped URLs but broke tracking, rate shopping, and token caching. Complete fix guide with custom carrier module, OAuth caching, and RevAddress drop-in.
WooCommerce USPS Shipping Plugin Migration: v3 REST API Guide
Fix broken WooCommerce USPS shipping after Web Tools retirement. Complete PHP code for custom shipping method, rate shopping, tracking, and drop-in RevAddress integration.
USPS API OAuth 401 Errors: Complete Troubleshooting Guide
Fix USPS v3 API 401 authentication errors. Covers OAuth 2.0 client_credentials flow, token endpoints, Content-Type mistakes, Payment Authorization, and debugging checklist.
USPS CRID and MID Enrollment: Complete Setup Guide for v3 API
Step-by-step guide to USPS CRID registration, Mailer ID (MID) enrollment, EPA setup, and COP claims linking for the v3 REST API. The guide that USPS PDFs should have been.
USPS v3 API with Node.js: Complete Quickstart Guide
Install the usps-v3 Node.js SDK and start validating addresses, querying tracking routes, and running USPS label workflows in minutes. Full TypeScript support, zero dependencies.
USPS v3 API with PHP: Complete Quickstart Guide
Install the revaddress/usps-v3-php Composer package and start validating addresses, querying tracking routes, and running USPS label workflows. Magento, WooCommerce, and Laravel integration.
EasyPost vs RevAddress: USPS Shipping API Pricing Compared
Factual pricing comparison between EasyPost and RevAddress for USPS shipping APIs. Per-label vs flat pricing math, feature comparison, and when each wins.
USPS Web Tools to v3 REST API: Complete Endpoint Mapping
Definitive USPS Web Tools XML to v3 REST mapping across addresses, tracking, labels, pricing, and locations.
USPS v3 API with Python: Complete Quickstart Guide
Install the usps-v3 Python SDK and start validating addresses, tracking packages, and comparing shipping rates in minutes.
USPS Web Tools to v3 REST: Complete Migration Guide
Step-by-step guide to migrating from USPS Web Tools XML API to the new v3 REST API. Endpoint mapping, OAuth setup, rate limit handling, and code samples.
USPS API Rate Limits: How to Handle 60 req/hr in Production
Practical strategies for handling USPS v3 API rate limits. Caching, batching, queue architecture, and BYOK for production workloads.