Primary-source baseline captured on 16 July 2026. Carrier acceptance, customs treatment, rates and schedules can change by shipment; recheck the linked authority and the accepting provider before cargo release.
A shipper’s letter of instruction is issued by the exporter to a freight forwarder or authorized agent to communicate shipment, routing, document and filing instructions. It is not a substitute for the commercial invoice, packing list, power of attorney, dangerous-goods declaration or carrier transport document. The exporter should approve the final SLI, identify which instructions are authorizations rather than preferences, and keep the accepted version linked to the booking and export record.
SLI authority and instruction matrix
Separate facts, preferences and delegated authority. A forwarder can act only within the appointment and instructions accepted for the shipment, while the exporter remains responsible for accurate source information.
Information-gain asset: Show the lifecycle of shipper’s letter of instruction: issuer, recipient, timing, mandatory fields, reconciliation checks, error recovery, and the evidence retained after release.
| Instruction group | Fact owner | Agent action | Approval evidence |
|---|---|---|---|
| Exporter and consignee | Exporter and buyer | Use legal parties in booking and documents | Approved legal identity and contacts |
| Cargo and classification | Exporter | Transmit description, Schedule B or other required data | Product and classification file |
| Routing and service | Exporter with forwarder advice | Book within accepted route and service | Quotation and booking approval |
| Electronic filing | Exporter or authorized filing party | File only under documented authorization | Power of attorney and filing instruction |
| Documents and insurance | Exporter and buyer | Prepare or route requested documents and coverage request | Named recipient, deadline and declared value |
Define the SLI’s role in the shipment record
The SLI is an instruction bridge between the exporter’s commercial facts and the forwarder’s operational work. It should identify the shipment and authorized actions without pretending to replace source documents or legal appointments.
Link the SLI to quotation, purchase order, commercial invoice, packing list, booking, power of attorney, filing record, dangerous-goods documents where applicable, insurance request and final AWB or B/L. Each record has a different owner and purpose even when data repeats.
State the SLI version, issue date, shipment reference, preparer and authorized approver. Define whether the forwarder may select routing within a service window, substitute a carrier, consolidate cargo, arrange insurance or make export filings. Silence should not be treated as broad authority.
Control party and exporter authorization fields
Use exact legal identities and current contacts. Exporter, USPPI where relevant, intermediate consignee, ultimate consignee, freight payer and notification contact can be different parties and should not be collapsed into one address block.
| Party field | Evidence | Authority question | Common failure |
|---|---|---|---|
| Exporter or principal party | Commercial and registration record | Who owns the export information? | Supplier and seller roles are confused |
| Forwarder or agent | Appointment and power of attorney | Which acts are authorized? | Old agent details are copied |
| Consignee | Buyer instruction | Who receives goods and documents? | Purchaser and ultimate receiver differ |
| Notify contact | Arrival workflow | Who handles carrier or broker exceptions? | A sales contact has no operational authority |
| Freight payer | Quotation and account instruction | Which charges and account are approved? | Incoterm is treated as a payment account |
Reconcile cargo, classification and filing instructions
The SLI should transmit specific commodity and quantity data supported by the invoice, packing and product file. Where export filing is required, the authorized filing party needs complete and timely data rather than a broad product nickname.
Record specific description, model or part identifier, quantity and unit, gross and net weight, package count, dimensions, value, currency, origin, classification reference and licence information where applicable. Identify which values are final and which remain estimates before warehouse verification.
If an agent will file export information, document authorization, filing responsibility, data deadline and correction process. The exporter should review filing evidence and keep it with the source facts. A forwarder should not invent classification, value or licence answers to meet a cutoff.
- Product description understandable outside the seller’s catalog.
- Classification and licence decision owner.
- Final package, weight and value source.
- Filing party, authorization and proof reference.
- Correction deadline and post-filing amendment owner.
Make routing and document preferences executable
A note such as fastest, cheapest or direct is not an operational instruction. Name the pickup, service, gateway or acceptable routing boundary, required arrival event, prohibited transshipment or carrier condition and decision owner for substitutions.
For documents, name each required item, issuer, original or electronic form, recipient, deadline and delivery method. If a letter of credit or buyer-specific legalization applies, the exporter should provide the exact requirement before transport documents are issued.
For insurance, state whether coverage is requested, the declared or insured value basis, commodity and packing, route, beneficiary or certificate recipient and deadline. A request to insure cannot be inferred from the goods’ value or Incoterm.
Manage SLI versions, exceptions and final archive
Route all changes through one controlled owner. A revised consignee, cargo value, package count, routing, filing instruction or document request can affect booking, customs, carrier and destination work.
| State | Required record | Forwarder action | Exporter control |
|---|---|---|---|
| Draft | Version and unresolved fields | Identify missing operational data | Do not authorize release |
| Approved | Authorized signature or accepted channel | Book and act within stated scope | Lock source facts |
| Exception | Trigger, proposed change and deadline | Pause or seek approval | Approve, reject or provide new data |
| Revised | Superseding version and change log | Update affected booking and records | Confirm every impacted party |
| Closed | Final SLI, booking, filing and document evidence | Archive linked records | Retain according to the exporter’s policy |
Worked instruction example: urgent air shipment with filing authority
An exporter asks a forwarder to collect six cartons, choose the fastest flight and handle all paperwork. The request lacks authority, final dimensions, classification, consignee role and insurance instructions, so the forwarder returns a controlled SLI draft.
- Identify exporter, authorized agent, ultimate consignee, notify contact and freight payer.
- Insert final cargo, value, classification, licence review and package data from source records.
- Define accepted airport or door scope, latest arrival event and substitution approval rule.
- Record filing authorization, data owner, proof required and correction process.
- Name transport documents, insurance decision, recipients and final archive owner.
The approved SLI gives the forwarder executable authority without transferring unknown product or compliance decisions. When the airline proposes a different route, the document identifies who can approve the exception and which records must be updated.
Failure controls before cargo release
Use this table as a stop-release check. A responsible owner should resolve each trigger against the same cargo and document version before the shipment moves to the next handoff.
| Failure trigger | Operational consequence | Required control |
|---|---|---|
| SLI says handle all paperwork | Agent authority and source-data ownership are undefined | List each authorized act and the exporter-owned facts that support it |
| Consignee is copied from an old shipment | Transport, filing and arrival records go to the wrong party | Approve legal identity and operational contact for this transaction |
| Classification is left for the forwarder to guess | Filing can be inaccurate or miss licence requirements | Provide an exporter-approved classification and product evidence file |
| Fastest route has no substitution boundary | Cost, transshipment or service changes without buyer approval | Define acceptable route, budget, deadline and exception owner |
| Revised SLI does not supersede prior copies | Different teams act on conflicting instructions | Use version identifiers, change log, distribution list and closure evidence |
Quote-ready data handoff
Send the inputs together and label estimates. This gives the forwarder, carrier, broker and consignee one controlled starting version instead of a price request assembled from conflicting messages.
- Exporter and authorized-agent legal identities and contacts.
- Consignee, ultimate receiver, notify party and freight payer.
- Final commodity, classification, licence and filing instructions.
- Package type, count, dimensions, gross weight and value.
- Pickup point, ready event, routing boundary and required arrival event.
- Carrier or service restrictions and substitution approval authority.
- Document list, issuer, form, recipient, method and deadline.
- Insurance decision, value basis and certificate recipient.
- Power of attorney, electronic filing role and proof requirement.
- Version, approver, amendment channel and record-retention owner.
Primary sources and verification boundary
These sources support the document, customs or dangerous-goods distinctions used in this guide. They do not replace a product-specific ruling, licensed customs advice or carrier acceptance for the actual shipment.
- U.S. International Trade Administration – Special Export Documents: A shipper’s letter of instruction is issued by the exporter to the forwarder and carries shipment instructions for air or ocean transport.
- U.S. International Trade Administration – Common Export Documents: Official distinctions among commercial invoices, packing lists, air waybills and ocean bills of lading.
- International Air Transport Association – e-freight and e-AWB: The air waybill is the contract of carriage between shipper and airline, and the e-AWB framework removes the paper requirement where adopted.
- General Administration of Customs of China – Import and Export Declaration Documents: China export declarations may require the contract, invoice, packing list, manifest, transport document and applicable licences to reconcile.
Related Sendwin resources and next actions
Use the links below to move from the reference answer into a live shipment decision. Each anchor identifies the destination topic so the relationship remains useful to buyers and search systems.
Connect the SLI to invoice, packing, filing and transport records shipping instruction and document guides.
Submit the final cargo, route and authorization brief freight quote with approved shipper instructions.
Translate service, routing, AWB and handling requirements into an executable handoff air freight booking instructions.
Control carrier, consolidation, B/L and destination-document requests ocean freight shipping instructions.
Distinguish fact ownership from delegated operational authority exporter, shipper and forwarder roles.
Keep classification, value, licensing and authorization evidence with the responsible party customs and filing data preparation.
Continue the shipping document workflow with the air waybill.
Frequently asked questions
The short answers below preserve the responsibility boundary. Confirm the actual cargo, date, lane, importer and accepting provider before relying on a general answer for release.
Who issues a shipper’s letter of instruction?
The exporter or shipper issues it to the freight forwarder or authorized agent. The forwarder can provide a form, but the exporter should supply accurate facts and approve the final instructions and authority.
Is an SLI the same as a power of attorney?
No. An SLI communicates shipment instructions. A power of attorney or other appointment establishes specified legal authority. Some workflows need both, and neither should be assumed from the other.
Does the SLI replace the commercial invoice?
No. The invoice records the commercial transaction and supports customs value and goods data. The SLI transmits operational and authorization instructions. Their overlapping facts should reconcile.
Can an SLI be changed after booking?
It can be revised through a controlled process, but a change may affect carrier booking, filing, documents, charges or destination work. Issue a superseding version, record approval and update every affected record.
Ready to test the plan against final cargo data? Request a shipment-specific freight quotation.