Shipper's Letter of Instruction
Instructions from the shipper to the freight forwarder on how to handle a shipment.
What It Is
A Shipper's Letter of Instruction (SLI) is an authorization document that provides the freight forwarder or carrier with detailed instructions for handling, booking, and documenting a shipment. It serves as the primary communication between the exporter and the logistics provider.
In the US, the SLI is particularly important as it authorizes the forwarder to act as the exporter's agent for export control and Electronic Export Information (EEI) filing purposes.
When It's Required
- US exports — Strongly recommended for all shipments; effectively required when the forwarder files EEI on the shipper's behalf
- Complex shipments — Multiple carriers, transshipment points, or special handling
- Dangerous goods — Additional handling instructions required
- Letter of credit transactions — Precise documentation instructions needed
Required Fields
| Field | Purpose |
|---|---|
| Shipper | Exporting party with full address |
| Consignee | Importing party with full address |
| Freight forwarder | Party receiving the instructions |
| Ship date | Requested shipment date |
| Transport mode | Air, sea, road, or multimodal |
| Origin / destination | Country and port/airport codes |
| Incoterms | Agreed trade terms (e.g., FOB, CIF) |
| Description of goods | Cargo description with HS codes |
| Number of packages | Package count and type |
| Gross weight | Total shipment weight |
| Declared value | Value for customs and insurance |
| Special instructions | Handling, routing, or documentation notes |
| EEI / AES filing authorization | Authorization for electronic export filing (US) |
Klervex Validation
Klervex validates that:
- Shipper and consignee details are complete
- Transport mode and Incoterms combination is valid
- Port/airport codes are valid UN/LOCODE or IATA codes
- HS codes are present for each line item
- EEI authorization is included for US-origin shipments