Introduction

The UniUni Platform Client API lets you programmatically create shipments, purchase labels, manage batches, track deliveries, and receive webhook notifications.

Environments

We provide both sandbox and production environments. Test your integration in sandbox first before going live.

Environment	Base URL
Sandbox	`https://api-sandbox.ship.uniuni.com/client/`
Production	`https://api.ship.uniuni.com/prod/client/`

All requests are HTTPS only.

Authentication

Every request must include your API access token in the Authorization header:

Authorization: Bearer <YOUR_ACCESS_TOKEN>

See Create Access Token for step-by-step instructions on generating and managing your tokens.

Request & response format

All requests and responses use JSON.
Use Content-Type: application/json; charset=utf-8 for POST bodies.
All object keys are in camelCase.
Response HTTP code is always 200 with a valid payload. Invalid payloads return HTTP 422.

Every response follows this structure:

{
  "message": "Shipment created successfully",
  "code": 0,
  "data": { ... }
}

Field	Type	Description
`message`	string	Additional information about the request status
`code`	integer	Status code (`0` indicates success)
`data`	object \| null	Response payload. Returns `null` if `code` is not `0`

Pagination

Collection endpoints support pagination via query parameters:

Parameter	Default	Max	Description
`page`	1	—	Page number
`pageSize`	10	500	Results per page

Sandbox testing

You can test your integration freely using the sandbox base URL. No charges will be incurred. Sandbox data is isolated and can be reset without affecting production. To add test credits in sandbox, use the test credit card number 4242 4242 4242 4242 with any expiry and CVC.

Error handling

422 Unprocessable Content

Returned when required parameters are missing or have the wrong type:

{
  "message": "Invalid payload [...]",
  "errorCode": "PayloadValidationError",
  "statusCode": 422,
  "meta": {
    "issues": [
      {
        "code": "invalid_type",
        "expected": "number",
        "received": "nan",
        "path": ["page"],
        "message": "Expected number, received nan"
      }
    ],
    "name": "ZodError"
  }
}

Authentication errors

{
  "message": "Invalid or revoked access token",
  "code": 1009,
  "data": null
}

{
  "message": "Missing access token",
  "code": 1009,
  "data": null
}

Error codes

Code	Reason
`0`	Success
`1002`	Invalid request
`1006`	Database error
`1009`	General error
`1014`	Resource not found (labels/batches)
`1031`	Tracking lookup failed

Core Concepts

API Endpoints

Webhooks

Environments

Authentication

Request & response format

Sandbox testing

Error handling

422 Unprocessable Content

Authentication errors

Error codes

​Environments

​Authentication

​Request & response format

​Pagination

​Sandbox testing

​Error handling

​422 Unprocessable Content

​Authentication errors

​Error codes

Environments

Authentication

Request & response format

Pagination

Sandbox testing

Error handling

422 Unprocessable Content

Authentication errors

Error codes