License & Deployment Mix: 10 tools – 0 OSS, 10 SaaS. (OSS and SaaS counts can overlap when an open-source tool also offers a vendor-hosted edition.)
Note: Data-primary – carrier rate tables.
What Are Shipping Rate Services?
Shipping rate services are a data-primary category. Unlike most tool evaluations where the value is in the software, shipping rate services derive their value from proprietary carrier rate tables – continuously updated databases of carrier pricing, negotiated discounts, surcharges, dimensional weight rules, and zone maps. The software (APIs, dashboards, label generators) is the front end for accessing this data.
OSS is not viable here. Open-source software cannot replicate the carrier rate agreements, volume discounts, and real-time surcharge tables that are negotiated between shipping platforms and carriers (USPS, UPS, FedEx, DHL, regional carriers). The product IS the rate data and carrier relationships, not the code that serves it.
The one exception is USPS Web Tools, a free government-provided API that gives direct access to USPS rates without a commercial intermediary. However, it is limited to USPS only and lacks the multi-carrier abstraction, label generation, and tracking aggregation that commercial platforms provide.
Shipping rate services are consumed through:
- Rate shopping APIs – real-time queries across multiple carriers to find the cheapest or fastest option for a given shipment
- Label generation – creating compliant shipping labels with barcodes, tracking numbers, and customs documentation
- Tracking aggregation – unified tracking across carriers via webhooks or polling
- Address validation – CASS-certified address verification to prevent delivery failures
- Customs and duties – cross-border shipping with automated duty calculation and customs forms
The information on these pages was researched by a combination of human review and large language models. To suggest an addition or correction, please contact us. Prepared by Rhodium Systems Inc., author of the ResorsIT platform — a unified IT operations management platform for IT teams and MSPs that integrates a curated suite of open-source, commercial, and SaaS applications into a single system with shared identity, single sign-on, access control, and a common audit trail. Use this catalogue only as a starting point for your own research, and review any tool carefully against your own requirements before relying on it. Catalogue data version 2026.197.
Comparison
Shipping rate services are evaluated as integration targets for ecommerce, warehouse management, and inventory management. API-level access uses API keys or OAuth 2.0 and is not affected by SSO configuration.
SSO / OIDC Comparison
OIDC is the preferred SSO protocol for portal access. The table notes each tool’s behaviour with Authentik as the IdP.
| Tool | OIDC | SAML | API Auth | Authentik Notes |
|---|---|---|---|---|
| EasyPost | No | No | API key | No SSO; API-key-only access |
| ShipStation | No | No | API key | No SSO; basic user/pass portal |
| Shippo | No | No | API key | No SSO; token-based API auth |
| ShipEngine | No | No | API key | No SSO; API-key-only access |
| Stamps.com | No | No | Credentials | No SSO; integration ID + credentials |
| Pitney Bowes | No | No | OAuth 2.0 | OAuth 2.0 client credentials for API |
| FedEx | No | No | OAuth 2.0 | OAuth 2.0 client credentials for API |
| UPS | No | No | OAuth 2.0 | OAuth 2.0 client credentials for API |
| USPS | No | No | API key | No SSO; registered user ID for API |
| Freightos | No | SAML* | API key | SAML for enterprise portal access |
* = available on enterprise plans only
SSO summary: Shipping rate services are primarily API-based; SSO is generally not applicable. Portal access for management UIs (ShipStation, Shippo) uses platform-native authentication. Enterprise platforms (Freightos) may offer SAML for portal SSO.
API Comparison
| Tool | API Type | Auth | Rate Limits |
|---|---|---|---|
| EasyPost | REST | API key | Tiered by plan |
| ShipStation | REST | API key + secret | 40 req/min |
| Shippo | REST | API token | Tiered by plan |
| ShipEngine | REST | API key | Tiered by plan |
| Stamps.com | REST / SOAP | Integration ID | Per-account |
| Pitney Bowes | REST | OAuth 2.0 | Per-endpoint |
| FedEx | REST (new) / SOAP (legacy) | OAuth 2.0 | 10K txn/day (free) |
| UPS | REST (new) / SOAP (legacy) | OAuth 2.0 | Per-endpoint |
| USPS | REST (new) / XML (legacy) | API key | 100K req/day |
| Freightos | REST | API key | Per-contract |
Shipping Features
| Tool | Carriers | Rate Shop | Labels | Tracking | Address Val | Cross-Border |
|---|---|---|---|---|---|---|
| EasyPost | 100+ | Yes | Yes | Yes (webhooks) | Yes | Yes |
| ShipStation | 70+ | Yes | Yes (batch) | Yes | Yes | Yes |
| Shippo | 85+ | Yes | Yes | Yes (webhooks) | Yes | Yes |
| ShipEngine | 60+ | Yes | Yes (batch) | Yes (webhooks) | Yes | Yes |
| Stamps.com | USPS, UPS | Limited | Yes (batch) | Yes | Yes | USPS intl |
| Pitney Bowes | Multi | Yes | Yes | Yes | Yes | Yes (advanced) |
| FedEx | FedEx only | N/A | Yes | Yes | Yes | Yes |
| UPS | UPS only | N/A | Yes | Yes | Yes | Yes |
| USPS | USPS only | N/A | No | Yes | Yes | USPS intl |
| Freightos | Air/Ocean/Land | Yes | Booking | Yes | No | Yes (freight) |
Deployment and Licensing
| Tool | License | Self-Hosted | Cloud/SaaS | Pricing Model |
|---|---|---|---|---|
| EasyPost | Proprietary | No | Yes | Per-label + per-tracking |
| ShipStation | Proprietary | No | Yes | Per-shipment/mo tiers |
| Shippo | Proprietary | No | Yes | Per-label or monthly |
| ShipEngine | Proprietary | No | Yes | Per-label + per-tracking |
| Stamps.com | Proprietary | No | Yes | Monthly sub + postage |
| Pitney Bowes | Proprietary | No | Yes | Enterprise contract |
| FedEx | Proprietary | No | Yes | Free API; pay for shipping |
| UPS | Proprietary | No | Yes | Free API; pay for shipping |
| USPS | Government | No | Yes | Free API; pay for postage |
| Freightos | Proprietary | No | Yes | Per-booking / enterprise |
Tools
10 tools.
EasyPost
EasyPost is a developer-focused multi-carrier shipping API that abstracts rate comparison, label generation, tracking, and address validation across 100+ carriers through a single REST interface.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
FedEx Web Services
FedEx Web Services is the official API suite provided by FedEx Corporation for programmatic access to FedEx shipping, rating, tracking, and address validation services.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Freightos (WebCargo)
Freightos is a global freight rate marketplace and digital booking platform for international shipping, covering air freight, ocean freight, and land transport.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: SAML
Pitney Bowes Shipping API
Pitney Bowes is a global shipping and mailing technology company founded in 1920, originally known for postage meters.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
ShipEngine
ShipEngine is a carrier-abstraction API owned by Auctane (the same parent company as ShipStation and Stamps.com) that provides rate comparison, label generation, address validation, and package tracking across 60+ carriers through a single…
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Shippo
Shippo is a multi-carrier shipping API platform that provides rate shopping, label generation, tracking, and address validation across 85+ carriers.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
ShipStation
ShipStation is a multi-carrier shipping platform owned by Auctane (formerly Stamps.com parent company) that targets ecommerce merchants with order management, batch label printing, and carrier rate comparison.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Stamps.com (Auctane)
Stamps.com is one of the oldest online postage and shipping platforms in the US, originally founded in 1996 as an authorized USPS PC Postage vendor.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
UPS Developer Kit
UPS Developer Kit is the official API suite provided by United Parcel Service for programmatic access to UPS shipping, rating, tracking, and address validation services.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
USPS Web Tools
USPS Web Tools is the free, government-provided API suite from the United States Postal Service for rate calculation, tracking, address validation, and other postal services.
License: LicenseRef-USPS-WebTools (source-available) · Kind: web · Deploy: saas · SSO: none
