Rate Shop GSO with EasyPost

EasyPost is a multi-carrier rate shopping shipping solution. The EasyPost API is one integration point for 100+ carriers, including GSO. All GSO functionality and pricing are accessible using the EasyPost API. EasyPost standardizes the inconsistencies across carrier APIs with its RESTful interface.

For access to all of the GSO API functionality through EasyPost, just sign up or get in touch with one of our shipping experts.

GSO, Golden State Overnight, is a West Coast regional carrier. With the following service levels GSO covers California, Nevada, and Arizona:

  • GSO Priority Overnight (PDS)
  • GSO Early Priority Overnight
  • GSO Ground (CPS)
  • GSO Saturday Delivery
  • GSO Early Saturday

GSO Rates can be found on these rate sheets.

GSO also has a Rate Calculator for one off rate inquiries.

To see how GSO compares to other carriers, see their Competitor Rate Comparison.

GSO, like FedEx and some other carriers, charges special handling fees based on Dimensional Weight when a package is light and bulky. Also, like most large carriers GSO charges a fee for undeliverable packages. That's why it's important to verify all your addresses with a shipping API, such as EasyPost.

In addition to Address Verification, EasyPost features Purchasing and Rating (with your negotiated rates), Tracking, and Status Updates. The EasyPost API is also Multi-Carrier, offering carriers such as FedEx, FedEx SmartPost, UPS, UPS Mail Innovations, USPS, USPS International, DHL, and more. It takes just seconds to sign up for an account and get an API key, and we have client libraries for .Net, Java, Node, Perl, PHP, Python, Ruby, and more.

For more pricing information, contact us and we'll connect you to a GSO sales representative.

Tracking Packages

Track packages across all major carriers.

Address Verification

Validate domestic and international addresses.

International & Customs

Learn how to handle international shipping seamlessly.

Shipping Insurance

Shipping insurance for all items sent with EasyPost.

EasyPost: Built for Developers

  • USPS Commercial Plus Pricing on ALL accounts
  • Instant Access to USPS, UPS, FedEx, and DHL & more
  • Try EasyPost for FREE, No Upfront Costs
  • Clients Libraries for .Net, Java, Ruby, Python, Node, and PHP
  • Millions of packages shipped each month using EasyPost!
# Create To and From Addresses
from_address = EasyPost::Address.create(...)
to_address = EasyPost::Address.create(...)

# Create Shipment and Get Rates
shipment = EasyPost::Shipment.create(
  from_address: from_address,
  to_address: to_address,
  parcel: {
    predefined_package: 'Parcel',
    weight: 32.8

# Buy Shipping Label
shipment.buy(rate: shipment.lowest_rate())

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Get Started with EasyPost Talk to a Shipping Expert

Sign up and start shipping in the same day. We have our GSO API live and ready for you to test with. We also have extensive client documentation in over six different languages to help you get started. If you have any questions, or if you want to talk logistics, feel free to reach out to one of our shipping experts.