@WisGal64 I don't know much more about it, I asked the support why they don't put the batch numbers on the vials, only the expiration dates, which seems to be about 2 years from the production date, even though they have some kind of batch numbers in their COAs.
Their answer:
All products are tested for endotoxins (LPS) and heavy metals as part of our full quality control process. The Certificates of Analysis (COAs) shown on our product pages match the batches we currently have in stock. When a new shipment arrives, the COAs are updated right away to reflect the new testing data.
While the vials themselves don’t list batch numbers, the COAs represent the full batch results, including the formula reference number, CAS number, Chem ID, and COA number. We share more data than most suppliers for full transparency.
You can view detailed composition percentages and measurements in the “Formula Testing” section, and each COA includes contact details for any questions or verification requests.
It's a copy-paste standard answer, I asked 2 times, got the same text.