Magento 2 USPS Shipping Extension – Real-Time USPS Rates via REST API v3

The ToweringMedia USPS OAuth Carrier for Magento 2.4 provides a secure and modern way to display real USPS shipping rates at checkout. Unlike legacy USPS modules, this extension integrates with the official USPS OAuth REST API (Domestic Prices v3) using secure OAuth 2.0 authentication, making it both future-proof and compliant with USPS requirements.

Merchants can configure allowed methods, automatically filter rates, and rely on USPS for accurate pricing — no more guesswork or outdated tables. Admin users can test connections and fetch sample rates directly within Magento, while structured logging ensures transparency without exposing secrets.

🔑 Features

• ✅ USPS OAuth REST API v3 Integration – Secure OAuth 2.0 authentication with the official USPS API.

• ✅ Real-Time USPS Rates – Live shipping quotes at checkout directly from USPS.

• ✅ Intelligent Rate Filtering – Automatically displays the most cost-effective shipping options, showing the cheapest option per service class (Priority Mail, First-Class, Ground Advantage, etc.) plus top-rated options by price.

• ✅ Admin Testing Tools – Built-in test endpoints for connection verification and sample rate fetching without leaving Magento Admin.

• ✅ Structured Logging – Comprehensive logging to var/log/usps_oauth.log for troubleshooting without exposing sensitive credentials.

• ✅ API Quota Protection – Integrated with Shipping Guard module to prevent API quota exhaustion during high-traffic periods.

• ✅ Broad Compatibility – Compatible with Magento 2.4.x, PHP 8.1+, MySQL 8.0+, and supports both OpenSearch and Elasticsearch.

⚡ Benefits

• 📦 Accurate Pricing – Real-time rates mean no overcharging or undercharging customers.

• 🔒 Future-Proof Technology – Modern OAuth authentication (no legacy username/password) ensures long-term compatibility with USPS requirements.

• 🚀 Time Savings – Eliminate manual shipping table maintenance and rate updates.

• 🛠 Easy Setup – Configure everything directly from Magento Admin with intuitive controls.

• 💰 Cost Control – Built-in API quota protection prevents unexpected charges during traffic spikes.

📋 What You Get

• Real-time rate calculations from USPS API

• Automatic rate filtering and optimization

• Admin testing tools for connection and rate verification

• Secure credential storage and management

• Comprehensive logging for troubleshooting

• API quota protection via integrated Shipping Guard module

• Easy Composer-based installation

🔧 Requirements

• Magento 2.4.x installation

• PHP 8.1 or higher

• USPS API credentials (Client ID and Client Secret) from your USPS account

• Active USPS API access

• Composer package manager

This Magento 2 USPS shipping extension is ideal for Magento 2 merchants in the US who want reliable, secure, and real-time USPS shipping rates integrated directly into checkout. Perfect for stores that need accurate shipping costs without the hassle of maintaining rate tables or worrying about outdated pricing. Compatible with Magento 2.4.8, Magento 2.4.7, and other Magento 2.4.x versions. Supports USPS OAuth, USPS REST API, USPS shipping calculator, and real-time USPS rates.

Magento 2 USPS Shipping Extension User Guide