Transportation API for 3PL Shipping Engines
Connect your own rating system to Slotted. When a brand needs shipping rates on a proposal, Slotted notifies your engine—you price the work and send rates back with API keys.
What the Transportation API Is
Slotted is not asking you to paste carrier product credentials into a plugin. The Transportation API is a bidirectional integration between Slotted and the shipping or rating engine you already run.
Slotted notifies your engine when rates are needed. Your system prices the work and posts rates back.
That keeps rating logic where it belongs—in your stack—while brands still get live shipping numbers on structured proposals.
Not a ShipStation or Carrier Plugin
This is not a place to paste ShipStation, EasyPost, or carrier credentials. You (or your developer) host an HTTPS webhook URL that receives Slotted events and calls Slotted back.
- You host the webhook—Slotted does not need a “return URL” inside a carrier product
- Portal API keys authenticate your system when sending rates back
- Sandbox keys are for practice; production keys are for live opportunities
How Live Rates Flow
Three steps from coverage to rates on the proposal.
1. Coverage on the Transport tab
On a proposal, set origins and coverage. When you are ready, use Send to engine.
2. Slotted calls your webhook
Slotted POSTs a rating request to your webhook with the shipping demand your engine needs to price.
Configure in the Provider Portal
Team admins create API keys and save sandbox and production webhook URLs under Transportation API settings in the provider profile.
Portal tests check that Slotted can reach your webhook and authenticate your keys. They do not replace a full live rate job on a proposal’s Transport tab.
Hand the Guide samples and public docs to your developer once keys and webhooks are in place.
- Create sandbox and production API keys in the portal
- Save your HTTPS webhook URLs
- Verify connectivity, then Send to engine on a live proposal
Public Developer Docs
OpenAPI and human-readable docs for the Transportation API are published at docs.slotted.com/transport/.
Keys are not self-serve from the docs site—they are issued and rotated in the provider portal. Partner opportunity intake is a separate, invite-only surface and is not open self-serve.
Ready to connect your shipping engine?
Read the public docs, or book a demo to walk through portal setup with your team.