# Certificate of authenticity

> A document issued by a recognised expert, the artist's foundation, the manufacturer or a certification body, attesting that an object is genuine. Its value depends entirely on the authority of the issuer.

- URL: https://www.selloff.auction/glossary/certificate-of-authenticity
- Language: English
- Also known as: COA, Certificate, Expert certificate
- Last updated: 2026-10-07
- Français: https://www.selloff.auction/fr/glossaire/certificat-d-authenticite.md

## Definition

A document issued by a recognised expert, the artist's foundation, the manufacturer or a certification body, attesting that an object is genuine. Its value depends entirely on the authority of the issuer.

Certificates are common for works of art, watches, jewellery, stamps and coins. For some categories, buyers expect one before bidding; for others, a lot may be sent for certification after the sale at the buyer's request.

In Selloff, certificate scans can be attached to lots, lots sent to a certification body are tracked until they come back as authentic or not, and a buyer's extension for an authenticity check blocks payment to the consignor until it is resolved.

## Related features

- [Photo import & image checks](https://www.selloff.auction/features/photo-import.md): Upload hundreds of photos at once, matched to lots by file name, with validation, required scan types and a coverage check before the catalogue goes to print.
- [Shipments & shipping slips](https://www.selloff.auction/features/shipments.md): Prepare and track shipments to buyers, consignor returns and lots sent for certification, with preparation slips and tracking emails.

## Related terms

- [Provenance](https://www.selloff.auction/glossary/provenance.md): The documented history of an object's ownership, from its creation or discovery to the present. A sound provenance supports authenticity and legal title, and can add to the object's value.
- [Grading](https://www.selloff.auction/glossary/grading.md): In numismatics, the assessment of a coin's or banknote's state of preservation on a recognised scale, such as the 1 to 70 Sheldon scale or descriptive grades like UNC, EF and VF. The grade strongly influences value.
- [Appraisal](https://www.selloff.auction/glossary/appraisal.md): A professional opinion of an object's value, given by a specialist for a specific purpose: sale at auction, insurance, division of an estate or tax. Auction estimates are one kind of appraisal.