James Allen is an American online diamond and bridal-jewellery retailer founded in 1998 by Oded Edelman and headquartered in New York. It was acquired by Signet Jewelers (the parent of Kay, Zales and Jared) in 2017 for approximately $328 million and continues to operate as a Signet brand. The site is one of the larger online channels for engagement-ring and loose-diamond purchases in North America, alongside Blue Nile, Brilliant Earth and the direct-to-consumer arms of the major lab-grown brands.

The principal commercial proposition is high-resolution 360-degree imagery of every stone in inventory, allowing online buyers to inspect a diamond's actual appearance rather than relying on grading-certificate text alone. The site offers GIA, IGI and AGS reports, lab-grown alongside natural diamonds, and a virtual ring-builder workflow. Pricing has historically run somewhat below traditional brick-and-mortar retail, reflecting lower distribution overhead and the direct relationship with Israeli, Indian and Antwerp cutters.

From a trade perspective, James Allen, Blue Nile and Brilliant Earth are part of the structural shift in the engagement-ring market over the past two decades from independent local jewellers to online channels with national reach. The shift has compressed margins for traditional retailers and has driven the growth of the lab-grown diamond segment by lowering transparency costs for consumers comparing natural and lab-grown alternatives.