EBay is expected to open its Selling Manager software to third-party developers.

An official announcement is due at the auction firm's annual eBay Developers Conference in Chicago today.

Selling Manager lets online auctioneers manage their sales listings on the eBay site.

The tool has traditionally used applications developed only by eBay itself, but by opening it up to external parties the firm hopes to benefit its merchants and developers alike.

Max Mancini, senior director of mobile platforms and disruptive innovation at eBay, claimed that the move is designed to take the company's open application development platform to the "next level".

It is expected that sellers will be able to search a directory of applications that will make it easier to run their online sales business.

It is not yet clear whether developers will have to pay to see their applications promoted, but it is reported that eBay will seek feedback on developers before finalising the details.

Selling Manager is currently used by around 700,000 eBay merchants.