A container arrives at your warehouse, and only then do you discover a third of the units have the wrong zipper color, or the carton count is short by 40 pieces. A pre-shipment inspection (PSI) exists specifically to catch problems like this while the goods are still at the factory — when there's still time to fix them before they're loaded onto a ship.
What a pre-shipment inspection actually is
A PSI is a quality check carried out by an independent third-party inspector at the factory, typically once production is 80-100% complete and the goods are packed and ready to ship. The inspector isn't a factory employee — they work for you, the buyer, and report findings back to you, not to the supplier. This independence is the entire point: a factory's own QC team has every incentive to pass its own goods.
The five things inspectors actually check
- •Appearance and workmanship — scratches, stains, uneven stitching, color consistency against your approved sample
- •Measurements and specifications — dimensions, weight, and materials checked against the approved spec sheet, not just 'close enough'
- •Function testing — does the zipper zip, does the switch switch, does the motor run, for a sample of units pulled at random
- •Quantity and carton count — physically counting cartons and spot-checking contents against the packing list, since shortages are one of the most common disputes
- •Packaging and labeling — correct barcodes, country-of-origin marks, and for Amazon-bound goods, FBA prep requirements like poly-bagging and suffocation warnings
AQL sampling: how much of the order actually gets checked
Inspectors don't open every carton — they use a statistical sampling method called AQL (Acceptable Quality Limit), most commonly AQL 2.5 for general consumer goods. For an order of 3,000 units, a standard AQL 2.5 sample size might mean physically checking around 200 pieces, not all 3,000. Defects are classified as critical (safety issues — automatic fail), major (functional problems, like a zipper that won't close), or minor (cosmetic issues, like a loose thread). Exceeding the allowed number of major or minor defects in the sample fails the whole batch.
What a passed vs. failed report looks like
A typical inspection report includes an overall pass/fail/pending verdict, a defect breakdown by category, carton and quantity counts, and dozens of photos documenting both the good units and any defects found. A 'fail' isn't necessarily the end of the order — it's leverage. Buyers who fail an inspection commonly negotiate a price discount, require a full rework before reshipping, or reject and reorder only the defective units rather than the entire batch.
When to schedule the inspection
Timing matters. Schedule it too early and the factory hasn't finished packing, so you can't check cartons or labeling. Schedule it too late — after the goods are already loaded into the container — and there's no time left to fix anything before the ship sails. The sweet spot is roughly 7-10 days before your planned shipment date, once production is essentially complete but before final loading begins.
What inspection can't catch
A PSI tells you the goods match your spec and sample on the day of inspection — it doesn't test long-term durability, won't catch a material substitution invisible to the eye, and isn't a substitute for lab testing if your product needs safety or compliance certification. Think of it as your last checkpoint for workmanship and quantity, not a guarantee the product will perform the same way after six months of real-world use.