Introduction
Last reviewed October 16, 2026
Start here to integrate with nShift. This page maps nShift’s seven APIs to what each one is for, from delivery options at checkout to shipment booking, tracking and returns, and links each one to its documentation, authentication model and, where published, its specification.
It is written for developers and the operations teams who work with them. Live status, release notes, support and security sit under Developer resources.
For machine readers, nshift.com/llms.txt summarizes this site, and the nShift Go documentation publishes docs.nshiftgo.com/llms.txt and an OpenAPI 3.1 specification.
Picking the right API
Choose the API that fits your use case. Each card shows how it authenticates and links to its documentation.
Checkout API
Show carrier options, prices, pickup points and delivery promises in an existing checkout, with testing functionality and bespoke labeling.
Also available as a widget or embedded service.
Auth OAuth2 client credentials through the nShift Portal
Docs Get started
Delivery API
Manage shipments, manifests, prices, printing, alerts and histories through REST endpoints, for an existing Delivery tenant on api.unifaun.com.
Auth API keys and developer ID
Docs Get started
Spec RAML 0.8
Go API
Build headless delivery into platforms and marketplaces, with full customization.
Auth OAuth with client ID and secret plus account ID
Docs Get started
Spec OpenAPI 3.1
Returns API
Push order data, pull return orders and summaries, and manage refunds in a returns experience you design.
Also available as a widget or embedded service.
Auth Basic auth with organization username and password
Docs Get started
Spec OpenAPI 3.0
Ship API
Automate high-volume shipment creation, rate selection through Shipping Rules, labels, EDI and manifests, and printing, for enterprise shipping label management.
Auth API keys and OAuth2
Docs Get started
Track API
Retrieve normalized tracking events, proof of delivery and shipment data across carriers, for tracking and analytics in your own experience.
Also available as a widget or embedded service.
Auth OAuth2 client credentials through the nShift Portal
Docs Get started
Transsmart API
Create, book and print shipments on Transsmart in multi-step flows, with SmartPrint and tracking.
Auth Basic auth, then a JWT bearer token
Docs Get started
Authentication & environments (at a glance)
- Checkout API uses OAuth2 client credentials through the nShift Portal. See: Checkout Getting started, ShipmentData API
- Ship API supports API keys and OAuth2. See: Ship - Getting started, Find your API key
- Delivery API uses API keys and developer ID on api.unifaun.com. See: Delivery API keys
- Transsmart API uses Basic auth → JWT → Bearer token. See: Transsmart Developer Docs
- Returns API uses Basic auth with organization username/password. See: Returns API documentation, Creating API keys
- Track API uses OAuth2 client credentials through the nShift Portal. See: Shipment Data API
- Go uses OAuth (clientId/secret + accountId). See: Go - Getting started.
Things that save you time
- Use Developer Tools in the Portal for live JSON requests/responses with Ship. See: Shipment Server integration guide
- Reference normalized tracking events across carriers: Normalized status names
- Use Transsmart BOOK/PRINT patterns when explicit control is needed: Transsmart Postman patterns
Notes for production hygiene
- Log request IDs and status transitions; build retries around immutable events, not assumptions
- Keep authentication scoped per API; rotate credentials via Portal policies
- Use test, beta, and acceptance environments before pushing production traffic
Developer resources
Release notes
Product changes, published per product in the Help Center. Browse release notes
System status
Live status for Checkout, Delivery, Go, Returns, Ship and Track at status.nshiftportal.com. Transsmart: statuspage.transsmart.com. nShift TMS and Web-TA: status.nshift.com.
Environments and support
Submit a support request in the Help Center. Signed-in customers find developer tools and API keys in the nShift Portal.
Security
ISO 27001 certified. A 99.9% uptime commitment in the Ship and Track service level agreement. Trust and security
Questions the docs don’t answer?
If you are evaluating nShift and need architecture, capacity, or rollout answers before you commit, talk to an integration specialist. Book a technical walkthrough, or start with the buyer evaluation pack for the product you are integrating.